(ISSN 0161-8202) tm t ^vT Journal of ARACHNOLOGY PUBLISHED BY THE AMERICAN ARACHNOLOGICAL SOCIETY 2014 NUMBER 2 VOLUME 42 THE JOURNAL OF ARACHNOLOGY EDITOR-IN-CHIEF: Robert B. Suter, Vassar College MANAGING EDITOR : Richard S. Vetter, University of California-Riverside SUBJECT EDITORS: Ecology — Stano Pekar, Masaryk University; Systematics — Mark Harvey, Western Aus- tralian Museum and Matjaz Kuntner, Scientific Research Centre of the Slovenian Academy of Sciences and Arts; Behavior — Elizabeth Jakob, University of Massachusetts Amherst; Morphology and Physiology’ — Jason Bond, Au- burn University EDITORIAL BOARD: Alan Cady, Miami University (Ohio); Jonathan Coddington, Smithsonian Institution; William Eberhard, Universidad de Costa Rica; Rosemary Gillespie, University of California, Berkeley; Charles Griswold, California Academy of Sciences; Marshal Hedin, San Diego State University; Marie Herberstein, Macquarie University; Yael Lubin, Ben-Gurion University of the Negev; Brent Qpell, Virginia Polytechnic Insti- tute & State University; Ann Rypstra, Miami University (Ohio); William Shear, Hampden- Sydney College; Jef- frey Shultz, University of Maryland; Petra Sierwald, Field Museum; Soren Toft, Aarhus University; I-Min Tso, Tunghai University (Taiwan). The Journal of Arachnology (ISSN 0161-8202), a publication devoted to the study of Arachnida, is published three times each year by The American Arachnological Society. Memberships (yearly): Membership is open to all those interested in Arachnida. Subscriptions to The Journal of Arachnology and American Arachnology (the newsletter), and annual meeting notices, are included with membership in the Society. Regular, $55; Students, $30; Institutional, $125. Inquiries should be directed to the Membership Secretary (see below). Back Issues: James Carrel, 209 Tucker Hall, Missouri University, Columbia, Missouri 6521 1-7400 USA. Telephone: (573) 882-3037. Undelivered Issues: Allen Press, Inc., 810 E. 10th Street, P.O. Box 368, Lawrence, Kansas 66044 USA. THE AMERICAN ARACHNOLOGICAL SOCIETY PRESIDENT: Charles Griswold (2013-2015), California Academy of Science, San Francisco, California, USA. PRESIDENT-ELECT: Marshal Hedin (2013-2015), San Diego State University, San Diego, California, USA. MEMBERSHIP SECRETARY: Jeffrey W. Shultz (appointed), Department of Entomology, University of Maryland, College Park, Maryland, USA. TREASURER: Karen Cangialosi, Department of Biology, Keene State College, Keene, New Hampshire, USA. SECRETARY: Paula Cushing, Denver Museum of Nature and Science, Denver, Colorado, USA. ARCHIVIST: Lenny Vincent, Fullerton College, Fullerton, California, USA. DIRECTORS: Jonathan Coddington (20 1 3-20 1 5), Richard S. Vetter (20 1 3-20 1 5), Michael Draney (2014-20 1 6) PARLIAMENTARIAN: Brent Opell (appointed) HONORARY MEMBERS: C.D. Dondale, H.W. Levi, A.F. Millidge. Cover photo: A female Eriophora sp, (Araneidae), possibly E.fuliginea, from La Selva, Costa Rica. Photo by Joe Warfel. Publication date: 15 August 2014 ©This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper). 2014. The Journal of Arachnology 42:135 141 The effect of forest stand characteristics on spider diversity and species composition in deciduous-coniferous mixed forests Ferenc Samu 1 , Gabor Lengvel 1 , Eva Szita 1 , Andras Bidlo 2 , and Peter Odor 2 : 'Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary. E-mail: samu.ferenc@agrar.mta.hu; department of Forest Site Diagnosis and Classification, University of West Hungary, Sopron, Hungary; ^Institute of Ecology and Botany, Centre for Ecological Research, Hungarian Academy of Sciences, Vacratot, Hungary Abstract. We studied how forest stand characteristics influence spider assemblage richness and composition in a forested region of Hungary. Deciduous-coniferous mixed forests dominate in the Orseg National Park. Thirty-five plots were established and sampled for spiders for three years in 70-1 10 year-old stands with a continuum of tree species composition. Detailed background information was acquired for stand structure, tree species composition, forest-floor-related variables and spatial position of the plots. The effect of variables was analyzed by nonparametric multiplicative regression on rarefied spider species richness and by redundancy analysis on species composition. The relative importance of variable groups was assessed by variation partitioning. Spider species richness was positively and strongly affected by tree species richness, and the species composition of the spider assemblage was influenced by the proportion of the most important tree species. This study established the importance of tree species composition, but variance partitioning analysis also showed that tree species identity and forest floor variables together explain much of the variation. These findings may guide management and conservation efforts to maintain regional diversity of the spider fauna. Keywords: Araneae, habitat model, species richness, non-parametric multiplicative regression, assemblage composition Spiders play an important role in forest ecosystems by occupying varied and crucial points in the forest food web and also by significantly contributing to forest biodiversity. In the classic study by Moulder and Reichle (1972) the fate of radioactive L,7 Cs isotopes was followed through the whole food chain of a Liriodendron forest, and spiders proved to be the most important predators of the forest litter community both in numbers and in biomass. Predation by spiders may also initiate cascading effects in the food chain; spiders preying on decomposers will lower the decay rate of plant material (Lawrence & Wise 2000). In removal experiments lack of spiders had a positive effect on populations of both herbivorous prey and smaller predatory arthropods (Clarke & Grant 1968). At the same time, we know that spiders present numerous predatory tactics and fill many different niches (Ending et al. 2007). Therefore, knowledge on species richness and functional diversity (Schuldt et al. 201 1) will lead us closer to understanding spiders’ roles in different forested habitats. Spider diversity in forests is influenced by many factors (Larrivee & Buddie 2010), and many studies address a certain set of variables, but many fewer take an integrative approach and compare the relative importance of various environmental factors. Several studies have underlined the importance of local factors (Niemela et al. 1996; Ending et al. 2007). Local variation creates high beta and consequently high gamma diversity (Schuldt et al. 2012) because a considerable proportion of forest spiders are habitat specialists (Floren et al. 2011). However, severe management practices that homogenize forest habitats lead to declines of sensitive species and beta diversity (Niemela 1997). Beside general patterns in diversity, many studies concen- trate on the role of vegetation structure and abiotic factors associated with microhabitats, especially at forest door level. The species distribution of forest-door spiders is significantly affected by litter type, structure, ambient light, humidity and temperature parameters (Uetz 1979; Varady-Szabo & Buddie 2006; Ziesche & Roth 2008; Sereda et al. 2012). Much more controversial than the effect of generally appreciated small-scale structural characteristics is the effect of tree species composition and stand structure on spider assemblages. The spider compositions of deciduous stands in a Canadian boreal forest (aspen and mixed wood) were very similar but distinct from those of spruce stands (Pearce et al. 2004). A study in central European forests found no significant difference in the abundance or species richness of spider assemblages associated with three coniferous species, while such a difference was found across different deciduous species (Korenko et al. 2011). Schuldt et al. (2008) found no general relationship between increasing tree species diversity and patterns of diversity and abundance in the spider communities of deciduous forest stands in Germany. Woody plant diversity affected spider assemblage structure, but not species richness, across 27 study plots in China (Schuldt et al. 2012 ). Given the relatively few studies that assess the importance of different groups of variables on forest spider communities, and the existing equivocal results on the role of stand type and tree species diversity, we intended to establish how much spider assemblages differ across different forest stand types with a continuum of tree species composition. We asked how tree species composition, stand structure and forest floor variables affect spider assemblages as well as the respective importance of these factors in determining local species richness and species composition. METHODS Study area. — Our study was conducted in forested areas of the Orseg National Park (46°51'55"N, 16°07'23"E), close to the borders of Hungary, Slovenia and Austria (Fig. 1). The 135 136 THE JOURNAL OF ARACHNOLOGY Figure F— The study area is Orseg National Park in the westernmost part of Hungary. The inset depicts the 35 locations containing the experimental plots. elevation is between 250-350 m, the average annual precipi- tation is 700-800 mm and the average annual temperature is 9.0-9. 5 °C (Dovenyi 2010). The Orseg National Park is dominated by beech ( Fagus sylvcitica L.), oak ( Quercus petraea L. and Q. robur L.), hornbeam ( Ccirpinus betulus L.), Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst.]. The dominant forest types are sessile oak-hornbeam woodland, acidofre- quent beech woodland, and acidofrequent mixed coniferous forest (see Odor et al. 2013). We selected 35 locations in mature stands (age 70-1 10 yr. old, size 2-10 ha) by stratified random sampling of the area (Fig. 1) from the database of the Hungarian National Forest Service, applying the selection criteria that the topography of the plots should be more or less flat and the topsoil should not be influenced by ground water. Stratification ensured that the selected locations represented the most common tree species combinations of the region, including a continuous gradient in the proportion of the main tree species. Within each location we established a 40 X 40 m plot, where environmental variables were determined. Variables. — Trees were mapped within the plots, forest floor vegetation and litter cover were estimated in quadrats and microclimate measurements were made. The original data collection resulted in a large number of variables (for more detail on measurements and methods, see Odor et al. 2013), but for the present study we considered only 21 variables. The variables represented four categories: 1) tree species compo- sition, which is tree species richness and the relative representation of main tree species, expressed as percentage relative tree volume; 2) stand structural variables (number, size, size variation of trees); 3) forest floor variables (coverage of main vegetation elements, litter and bare soil, plus microclimatic variables) and 4) spatial component, represent- ed by x, y spatial coordinates of plot center. These four groups largely cover environmental variables that according to the literature (detailed in the Introduction) were likely to exert an effect on spider distribution in a forest habitat. The variables are listed, described and categorized in Supplemental Table 1 (online at http://www.bioone.org/doi/suppl/10.1636/CP13-75). Table 1 . —Sampling dates and sampling efforts in the 35 forested plots of Orseg National Park. Suction sampling Pitfall trapping Campaign date samples/plot traps/plot days open 06/07/2009 3 5 31 08/10/2009 5 5 28 01/10/2010 8 5 27 28/05/2012 - 5 30 All explanatory variables were standardized for statistical modelling (zero mean, one standard deviation). Sampling. — Spiders were collected from each plot by pitfall trapping and suction sampling during four sampling cam- paigns in the most species-rich periods: summer and autumn. Such a time-limited sampling approach, optimized for the most species rich periods, is recommended for the comparison of assemblages at a large number of localities (Jimenez- Valverde & Lobo 2006). Sampling dates and sampling efforts are summarised in Table 1. Five pitfall traps were deployed in a plot during a campaign: one placed in the center, the other four forming a square of ca. 1 5 m sides positioned symmetrically around the center. Pitfalls were plastic cups of 75 mm upper diameter filled with 70% ethylene glycol as preservative, with some detergent added (Kadar & Samu 2006). Traps were open for a month; the catch was sorted and spiders stored in 70% ethanol until identifi- cation. Voucher specimens were placed in the collection of the Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences. Suction sampling was performed with a hand-held motorized suction sampler, fitted with a 0.01 nr orifice (Samu & Sarospataki 1995). We tried to sample all microhabitats in a forest stand up to 1.5 m height with suction sampling. One sample lasted for ca. 60 s, consisting of several applications of the sampler, in which we first sampled from microhabitats that produced the least debris (e.g., leaves from bushes and lower branches of trees and trunks), then we continuously sampled other habitats (such as dead wood surface, gravel surfaces, patches of terricolous mosses), and only in the last couple of applications was litter and soil sampled, because it could potentially congest the apparatus. This way each sample was a cross section of the microhabitats of a smaller area within the 40X40 m plot. Since the number of specimens caught was smaller than we initially expected, we increased the number of samples per plot over the campaigns (see Table 1). Because of variable catches per sample, all samples from a plot across methods and dates were lumped and used that way in data analysis. Data analysis. — We estimated spider species richness for the whole area by calculating the non-parametric species estimator Chaol (Chao et ah 2005) using the software Estimates version 9.0 (Colwell 2013). We also calculated the Chaol estimator separately for each plot and observed that in five plots estimated Chaol values showed erratic behavior along the species accumulation curve, which is a sign that the spider assemblage may have been under sampled at those plots (Colwell 2013). These plots were excluded from species richness modelling. To establish plot level species richness estimates for the 30 plots not excluded based on Chaol behaviour, we used the more conservative rarefraction method. We made estima- SAMU ET AL. -EFFECT OF TREE COMPOSITION ON SPIDER ASSEMBLAGE 137 tions of species richness rarefied to 75 individuals (S 75 , mean number of adult individuals caught in the plots was 74.2) using the individual-based abundance model of Colwell et al. (2012) as implemented in Estimates (Colwell 2013). We explored how species richness is influenced by environ- mental variables using Nonparametric Multiplicative Regres- sion (NPMR), carried out by Hyperniche 2 (McCune & Mefford 2009). The NPMR method (McCune 2004) predicts a univariate response (e.g., abundance of a species or species richness of a community) at a target locality from other localities that are close to the target locality in the environmental space. The response surface resulting from predictions for each locality can be of any shape and is not determined by a certain function (hence non-parametric). The local mean method, applied here, weights neighboring responses according to vicinity in the environmental space by a Gaussian weighting function. Response from localities where environmental variables have the same values as at the target locality would receive a weight of one; response at less similar localities are weighted decreasingly according to the weighting function. Multivariate weights are gained multipli- catively. The width of the weighting function (standard deviation of the Gaussian function) is termed tolerance and during fitting is optimized for each variable. Variable selection and optimization is done iteratively maximizing the cross- validated coefficient of determination (xR 2 , meaning that the observed response at a given point is not included in the estimation of the response), and its significance is tested by Monte-Carlo simulation (McCune 2004). Gaussian local mean NPMR was applied to S 75 at 30 localities. The method requires positive values, therefore we added a constant (c = 4, the smallest natural number that made all values positive) to the values of the standardized explanatory variables. To study the multivariate response of species to environ- mental variables. Redundancy Analysis [RDA, carried out by Canoco 4.5 (Ter Braak & Smilauer 2002)] was performed, supposing approximately linear relationships between species performance and explanatory variables (Leps & Smilauer 2003). In preliminary Detrended Correspondence Analysis the gradient lengths of the main axes were short (1. 9-2.1 SD units), supporting linear relationships. Rare species (frequency less than 4) were excluded from the analysis. The same initial set of explanatory variables was used as for the NPMR model (Suppl. Table 1). The explanatory variables were selected by manual forward selection, and their effect and the significance of the canonical axes was tested by F-statistics via Monte- Carlo simulation (Ter Braak & Smilauer 2002). Because spatial coordinates had a significant effect after model selection, the analysis was repeated using them as covariates (Ter Braak & Smilauer 2002). Variation partitioning was carried out to explore the amount of variance in the species assemblages accounted for by the four categories of explan- atory variables (Peres-Neto et al. 2006). All 21 explanatory variables were included in variation partitioning, which was carried out in R 3.0.2. (R Core Team 2013) using the vegan package (Oksanen et al. 2011). RESULTS Species richness estimation. — During the study 4567 spiders were caught, distributed nearly equally among the two Table 2. — Best local mean model of species number rarefied to 75 individuals, fitted by NPMR model (McCune & Mefford 2009) with conservative over-fitting control. The best model based on xR : included three variables: tree species richness, relative volume of Scots pine and shrub density. Min. and Max. refer to the minimum and maximum value of the given variable on the standardized scale. Tolerance is one standard deviation of the Gaussian smoothing function by which the optima! model was reached. Tol. % is the percentage of Tolerance to the data range (Max.-Min.). Variable Min. Max. Tolerance Tol.% Tree species richness 2.13 6.25 0.91 22 Scots pine rel. volume 2.95 5.80 0.77 27 Shrub density 3.14 7.41 0.64 15 sampling methods (suction sampling: 2245, pitfall trapping: 2322 individuals). Out of the total catch 2596 spiders were adults; these represented 91 species (Suppl. Table 2; online at http://www.bioone.org/doi/suppl/10. 1636/CP 13-75). In species richness estimation of the species pool of forest spiders, we presumed that samples from the 35 localities were representative of the regional forest spider fauna accessible with the given sampling protocol. Chaol species richness estimator (S C haoi) was calculated along the species accumula- tion curve. It reached its peak value at 1589 individuals, where it gave an estimate of S C haoi = 103.4 species, from where it gradually declined, and at full sample size reached S C haoi = 100.5 species with CI 95% = 94.1-1 19.9. For the 30 plots where the Chaol estimator was stable, mean species number was 18.2 (CI 95% =!2.5, 23.8). Chao! species richness was on average 25.1 (CI 95% = 19.3, 52.2). Rarefied species number environmental model. — We applied local Gaussian mean NPMR to establish which environmental variables are the best in predicting rarefied species number. The best model (Table 2, Fig. 2) included three explanatory variables: tree species richness, proportion of Scots pine by volume and shrub density. Spatial variables entered in the initial model fell out during iterative variable selection. With xR~ = 0.596, it explained ca. 60% of variance in S 75 , and was highly significant (P = 0.009) in the randomization test. Spider assemblage environmental model. — After the exclu- sion of rare species, 45 species were used in RDA. In the final RDA model canonical variables explained 31.2% of the total species variance, with the first (F = 6.22, P = 0.002) and all canonical axes (F = 3.18, P = 0.002) being significant based on Monte-Carlo simulation. The most important explanatory variables were the relative volume of oak (k A = 0.10, P = 0.002), beech (k A — 0.06, P — 0.004), hornbeam (A, a = 0.05, P = 0.004) and air humidity (X A = 0.04, P = 0.006) (Fig. 3.). Variation partitioning showed that the four variable groups of the RDA (this time not treating the spatial component as a co-variable) explained 35% of the variation. The most variation was explained by tree species composition (26%) and the least by stand structure (16%) (Fig. 4). However, most of the variation was shared between variable groups. The highest shared variation was between tree species composition and forest floor variables (16%). Spatial component alone was responsible for only 7% of the total variation (Fig. 4). RDA ordination indicated that spider species responded to the environmental gradients in a continuous way; they were rather evenly distributed around the ordination center 138 THE JOURNAL OF ARACHNOLOGY Figure 2. Response surface of the best local mean NPMR model on rarefied species number, depicted for the first two predictor variables (for further explanation see text and Table 2). (Fig. 3). Nevertheless, an oak-hornbeam gradient could be discerned along Axis 1, with the wolf spiders Pardosa lugubris (Walckenaer 1802) and Trochosa terricola Thorell 1856 markedly associated with oak, while Histopona torpida (C.L. Koch 1834), a funnel web weaver species, was strongly associated with hornbeam. Other species such as Cicurina cicur (Fabricius 1793) and Maltlwnica silvestris (L. Koch 1872) had a preference for both hornbeam and humidity. A number of hunters (. Harpactea lepida (C. L. Koch 1838), Clubiona terrestris Westring 1851, Dysdera ninnii Canestrini 1868) and some linyphiid species [Drapetisca socialis (Sundevall 1833), Micrargus herbigradus (Blackwall 1854)] were associated with beech. Beech-hornbeam mixed stands occurred in the area, and the amauroboid species Eurocoelotes inermis (L. Koch 1855) seemed to be strongly associated with this stand type. Air humidity vs. dryness comprised another significant gradient, with Macrcirgus rufus (Wider 1834) associated with humid conditions and Mangora acalypha (Walckenaer 1802) with dry conditions. The latter orb weaver is mostly known from open grassland habitats. There were, however, quite a number of species positioned intermediate between oak and humidity [e.g., Agroeca brunnea (Blackwall 1833), Lepthy- phantes minutus (Blackwall 1833) and Haplodrassus dalmaten- sis (L. Koch 1866)] that could not be associated with environmental variables based on the present analysis (Fig. 3). DISCUSSION In the present study we explored the basic but still unresolved problem of how spiders depend on stand scale vegetation features. In the forested area of the Orseg National Park, deciduous and mixed forests show a continuum of tree species composition. By studying spider assemblages in 35 localities, we wanted not only to assess regional species richness, but also its variability depending on an extensive set of variables related to the forest stands. Our sampling efforts were limited to certain times of the year and certain microhabitats accessible by the sampling protocol and were mostly suited to make comparisons across the localities (Jimenez-Valverde & Lobo 2006). Still, our richness estimate of 95-120 species (with 95% confidence) was very similar to values reported from temperate forests (Coddington et al. 1996) and approximates the species number of 149 found in the Uzungwa Mountains of Tanzania (Sorensen 2004). We collected a considerable amount of data about the forest plots, out of which we used 21 variables in four variable groups to explore the dependencies of species richness and composition. Since sampling resulted in a variable number of individuals, we used individual- based rarefied richness values for comparison. In a Canadian case study rarefied species richness standardized to the number of individuals enabled the most accurate comparisons, especially when sampling was limited (Buddie et al. 2005). To analyse the importance of environmental variables we applied non-parametric methods that made no assumptions about species response and used rarefied richness data only from plots where sampling proved to be adequate. Tree species richness of the forest stands proved to be the most influential factor of spider species richness. Although intuitively expected in the light of other studies (De Bakker et al. 2000; Pearce et al. 2004; Ziesche & Roth 2008), this is a notable result, especially because our survey took into account a spectrum of different environmental variables including micro- climatic factors, forest floor cover, stand structure and spatiality. Other studies have typically concentrated on a narrower range of explanatory variables. Small-scale studies could show the importance of structural and abiotic features (Varady-Szabo & Buddie 2006; Sereda et al. 2012), while large- scale studies showed the negative effects of habitat homogeni- zation and the importance of species pool and connectivity to nearby habitats (Niemela 1997; Floren et al. 2011). Tree species are in fact connected to all these levels - they have various structural aspects and also affect forest floor variables. In the present study where variables representing four different groups were entered into the models, the most influential level of variables was how variable the tree composition was; i.e., how many tree species were present in a plot. SAMU ET AL. EFFECT OF TREE COMPOSITION ON SPIDER ASSEMBLAGE 139 Figure 3. — RDA ordination diagram of species in relation to environmental variables. Hornbeam, oak, beech: relative volume of the tree species in the stands; air humidity is mean daily air humidity based on eight measurements. Species abbreviations are composed from the first four letters of the generic and species name of each species (for species list see Suppl. Table 2; online at http://www.bioone.org/doi/suppl/10.1636/ CPI 3-75). Although it is only logical that if the number of tree species influences spider richness, then spider species composition should be influenced by tree species composition, not all previous studies warrant this outcome (Pearce et al. 2004; Oxbrough et al. 2012). In a study where association between spider species in different tree species was investigated, the outcome was different between deciduous and pine trees (Korenko et al. 2011). The physiognomy of forest stands characterized by certain tree species also determines abiotic factors, such as microclimate and litter characteristics, and also determines the quality of undergrowth. Our variation partitioning showed that this is indeed the case. Tree species composition and forest floor characteristics together explain the most variation in spider species distribution, but if single variables are considered, then the complexity of many environmental factors seems to be united (and most easily measured) in tree species. Associations, such as the correlation of wolf spiders with higher preferences for open habitats (Hanggi et al. 1995) with oak, are likely to have a complex explanation including litter type and microclimatic conditions, which are all related to the dominant tree species. We can see examples of other associations that may be determined by the specific microhabitats certain tree species provide - for instance the occurrence of Drapetisca spp. on smooth bark surfaces, which are provided by beech (Hovemeyer & Stippich 2000; Larrivee & Buddie 2010). We argue that tree species seem to provide smaller-scale environmental features in such combinations, that — as the present study indicates — tree species composition becomes the most relevant variable determining spider assemblage richness and structure. This finding is important, because it highlights the significance of a certain level of abiotic-biotic organiza- tion. Tree species richness is a key factor for many other organism groups like bryophytes (Kiraly et al. 2013) and forest floor plants (Marialigeti et al. 2009). The present results also emphasize that conservation-oriented forest management should focus on the maintenance of tree species richness and mixed tree species. 140 THE JOURNAL OF ARACHNOLOGY Figure 4. — Variation partitioning of species-environmental vari- ables in RDA analysis. Variables in the original analysis were grouped into tree species composition, stand structure, forest floor related variables and spatial component. Shared variation fractions are noted on the Venn diagram. ACKNOWLEDGEMENTS We thank Andras Rakoczi, Kinga Fetyko, Laszlo Bod- onczi, Gergely Kutszegi, Zsuzsa Mag, Sara Marialigeti, Istvan Mazal, Akos Molnar, Balazs Nemeth and Flora Tinya for their help in the field survey, and Erika Botos and Zsuzsanna Benedikty Konczne for help in laboratory work. 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Biodiversity and Conservation 15:4119^1141. Ziesche, T.M. & M. Roth. 2008. Influence of environmental parameters on small-scale distribution of soil-dwelling spiders in forests: What makes the difference, tree species or microhabitat? Forest Ecology and Management 255:738-752. Manuscript received 1 October 2013, revised 13 December 2013. 2014. The Journal of Arachnology 42:142-147 Progress and prospects in taxonomy: what is our goal and are we ever going to reach it? Bernhard A. Huber: Alexander Koenig Research Museum of Zoology, Adenauerallee 160, 53113 Bonn, Germany Email: b.huber@zfmk.de Abstract. Based on percentages of undescribed species collected during intensive recent sampling campaigns in South America, tropical Africa, and the Caribbean, the current global total number of pholcid species is estimated to range from about 4,000 to 5,000. With the current rate of descriptions of about 570 pholcid species per decade, this suggests that a global inventory of the family could be completed within a few decades. However, 1 argue that a complete (or near- complete) inventory is neither realistic nor necessary and that knowing the majority of species of a particular group will answer most questions on that taxon’s biology, while being a manageable task. At current rates of description, the majority of pholcid species might be known within 10-20 years. Keywords: Spiders, Pholcidae, global diversity, description rate, taxonomic impediment, extrapolation There is a wide range of positions about the progress and prospects of taxonomy. One extreme is characterized by a rather pessimistic view, based on the fact that taxonomists have described no more than about 5-20% of global diversity in over 250 years (e.g.. Stork 1997; Guerra-Garcia et al. 2008; Hamilton et al. 2010); on the impression that all sorts of fundamental prerequisites are increasingly difficult to access, including funds, academic positions, and permits for collecting and export (e.g., Gaston & May 1992; Wilson 2004; Haas & Hauser 2005; Amato & DeSalle 2012; Bebber et al. 2013; de Carvalho et al. 2013; Lobl & Leschen 2013; Sluys 2013); on the insight that modern taxonomy is not only solving problems but also creating new ones, as by the current explosion of DNA sequences in online repositories not linked to described species (Samyn & De Clerck 2012); on the awareness that we live in an ‘age of extinction' (e.g.. Stork 1997; Amato & DeSalle 2012; Mora et al. 2013); and on the uneasy suspicion that taxonomy makes us feel we ‘know’ a species after describing it while in fact we know almost nothing about most described species (e.g., Lawton 1993). On the other extreme there is a confident ‘yes, we can’ position, based on impressive numbers of species described every year, on supposedly increasing rates of species description by increasing numbers of taxonomists, and on the ongoing development of infrastructure and technology (e.g., Janzen 2004; Joppa et al. 201 1; Wheeler et al. 2012; Costello et al. 2013a, b). The present paper challenges these extremes but primarily intends to address the problem at a much smaller scale, dealing with a single family of spiders, the Pholcidae. This is simply a result of my own emphasis on and experience with this group for almost two decades. I do not pretend that the results can or should be easily extrapolated to other spiders or even beyond (for recent thoughts at that scope, see Agnarsson et al. 2013; Platnick & Raven 2013). Acknowledging the need for clearly achievable goals that are both realistic and relevant (God fray 2002), I aim at a picture that is as close to reality as possible, in an effort to avoid both debilitating hopelessness and overly enthusiastic confidence. ESTIMATING GLOBAL SPECIES DIVERSITY In the early days of arachnology, the pioneering French- American zoologist Nicolas Hentz published a remarkable statement, saying that “...when the work is accomplished, and all nature is described by man, the number of species included in the common word spider will be truly amazing. ... It is obvious that the number of species throughout the world will amount to more than two thousand...” (Hentz 1841: his italics). Current estimates of global spider diversity (76,000- 170,000: Coddington & Levi 1991; Platnick 1999; Agnarsson et al. 2013; Platnick & Raven 2013) are obviously closer to reality, but the wide range of estimates also shows that we still have to build on incomplete data and make extrapolations based on debatable assumptions. A variety of methods have been proposed to estimate species diversity, each with its strengths and weaknesses, including ratios from known to unknown faunas; extrapolations from samples; relationships of body size and species number; rates of species description; species turnover; and expert opinion (e.g.. Stork 1997; Mora et al. 2011; Scheffers et al. 2012). The approach used here is similar to that in Hodkinson & Casson (1991), who employed percentages of new species collected during intensive sampling events (the “known to unknown ratio” method in Mora et al. 2011). In contrast to previous studies using this approach, I try to avoid two pitfalls: 1) by comparing results from mega-transects in different regions I hope to minimize the potential impact of unjustified extrapolation from regional to global species richness; 2) by focusing on Pholcidae I limit the results to a relatively small taxon (currently about 1400 nominal species), avoiding further assumptions needed for extrapolating to total spider or even total species richness. The estimates below are based on a series of 15 recent collecting trips to Brazil, the Caribbean and tropical Africa (for details see http://www.pholcidae.de/expeditions.html). The primary aim in each of these expeditions was to collect a maximum of pholcid species present at each locality. For this reason, common and easy species were deliberately ignored after an initial period and the effort was increasingly focused on more cryptic and ‘difficult’ species. This method obviously impedes an analysis of species abundances within and among localities, but it is likely to collect most or all species with considerably less effort than a strict quantitative approach in ecologically structured sampling. Atlantic Forest niega-transect. -In five expeditions (2003— 201 1), 17 localities in Brazil’s Atlantic Forest were visited over 142 HUBER PROGRESS AND PROSPECTS IN TAXONOMY Figure 1. — Localities in Brazil’s Atlantic Forest visited between 2003 and 2011, resulting in a total of 89 pholcid species, 71 of them new to science. a transect of 2,000 km (Fig. 1). Species accumulation curves for total and new species do not seem to slow down in the addition of new species over time. The percentage of new species remained relatively constant over the transect, with a final value of 80% (71 of 89) (Fig. 2). Tropical Africa mega-transect. — In six expeditions (2008- 2013), about 75 localities across tropical Africa were visited over a transect of 6,000 km (Fig. 3). Even though species diversity per locality and levels of endemism were lower than in Brazil, the species accumulation curves for total and new species are similar (Fig. 4). The percentage of new species remained relatively constant over the transect, with a final value of 74% (87 of 1 1 7) (Fig. 4). Comparative data on Caribbean islands. About 45 localities on Cuba, Haiti and the Dominican Republic were visited in four expeditions (1999-2012). The total percentage of new species was similar to those in Brazil and Africa: 78% (62 of 80). Preliminary conclusions. -The three intensive sampling events over large geographic areas resulted in similar percent- ages of new species (Brazil: 80%, Africa: 74%, Caribbean: 78%). I see no reason to expect significantly different percentages for other megadiverse regions like Southeast Asia or other parts of tropical South America. For regions that are better studied (e.g., Europe, North America), percentages are likely lower, but their relatively low pholcid diversity suggests little impact on the total numbers. Extrapolation based on numbers of described species before major description of new taxa collected during the above sampling events (—1,000 species as of 2008) suggests a global total of about 4,000-5,000 pholcid species. Whether these numbers are closer to reality than the quick-and-dirty expert opinion I offered in May 2012 (6,770 species: published in Agnarsson et al. 2013), only the future can show (the illusory precision resulted from the fact that my rough guess of 5,500 undescribed species was added to the number of nominal species known at that time). 143 Figure 2. — Species accumulation curves for total and new pholcid species collected at the Brazilian Atlantic Forest localities shown in Fig. 1 during 46 days of fieldwork. RATES OF DESCRIPTION The species accumulation curve of Pholcidae from Linnaeus to present shown in Fig. 5 primarily reflects the increasing specialization of taxonomists on ever fewer and/or smaller taxa. One remarkable feature of the curve is its fairly steady exponential increase. Four phases can be distinguished, with increasing rates but decreasing duration: 1757-1889 ( 132 years, 2 species/decade); 1890-1970(81 years, 31 species/decade); 1971- 1999 (29 years, 1 10 species/decade); 2000-present ( 14 years, 572 species/decade). Apart from the trivial conclusion that an average rate over the last 250 years is misleading for extrapolation, the curve suggests that even current rates may not be a solid basis for extrapolation. A PLEA FOR THE MAJORITY Recent contributions on the subject almost universally imply that nothing less than naming and cataloguing all [my emphasis] life on Earth is a major and unquestioned goal of taxonomy (e.g., Carbayo & Marques 2011; Wheeler et al. 2012; Bebber et al. 2013; Costello et al. 2013a; Didham et al. 2013). For groups such as plants and vertebrates this may be a feasible goal. For megadiverse arthropod groups, however, aiming for the majority of species rather than a complete or near-complete inventory of global diversity seems an attractive and justified approach for three reasons: 1) I strongly agree with May (2004) that collecting new species in the field will remain the rate-limiting step in taxonomy. The more species we collect and describe, the higher will be the percentage of ‘difficult’ species among those that remain undescribed; i.e., species that are rare, cryptic, small, limited to poorly accessible areas, etc. (Mora et al. 2011; Scheffers et al. 2012). Finding these species will require increasing numbers of specialists (generalist collectors inevitably tend to recollect the ‘easy’ species) in increasingly difficult areas (e.g., the landmine- infested forests in Angola; see http://www.sac-na.org/ 144 THE JOURNAL OF ARACHNOLOGY Figure 3. — Localities in tropical Africa visited between 2008 and 2013, resulting in a total of 117 pholcid species, 87 of them new to science. surveys_angola.html), spending increasing amounts of time and money (at some point the seemingly absurd estimate of Carbayo & Marques 2011 of US$ 48,500 per species may become realistic), and facing increasing bureaucratic hurdles on the way to the field and back. It is a mystery to me how Wheeler et al. (2012) could unequivocally agree with the statement that “a compre- hensive mission to discover ... the species of the biosphere is feasible”. These authors call for an “aggressive expansion of collections”, remaining silent about what this means and how it works. 2) As I will suggest below, aiming for the majority of species may result in a much less intimidating period of time necessary to achieve the goal (and thus help avoid the feeling of hopelessness). 3) 1 propose that knowing half of all species of each taxon will get us very far in providing the basis for answering Figure 4.- Species accumulation curves for total and new pholcid species collected at the African localities shown in Fig. 3 during 106 days of field work. our questions about all aspects of nature ranging from molecules to ecosystems. The half of the species described first from a particular taxon will probably include most species a non-specialist will ever encounter in the field, it will likely be a good representation of the geographic range and the morphological and molecular variation within the taxon, it will allow estimation of biases (such as biases in collecting effort, or the bias for widespread species: see below) and it will probably reflect the basic patterns of the group's natural history and point out the most promising aspects for further in-depth studies in and beyond taxonomy. CONCLUSION - IT NEED NOT TAKE HUNDREDS OF YEARS In a recent paper on tropica! arthropod species richness estimation, Hamilton et al. (2010) concluded that “... 66%- 77% of arthropod species are yet to be described ... [and that it] will take hundreds of years to complete at the current rate Figure 5. — Cumulative curve of currently valid described pholcid species up to September 2013. HUBER -PROGRESS AND PROSPECTS IN TAXONOMY 145 A B o VO O in o o fN O -J 4 6 8 10 localities E 0 a> c ro 'new' 'old' status Figure 6. — Atlantic Forest transect. A. Histogram showing that a large majority of species was found at only one or few of the 17 localities sampled. B. C. Boxplots showing that ‘new' species (i.e., undescribed species as of December 2003, the date of the first trip) have significantly smaller ranges [both in terms of numbers of localities (P = 0.004) and with respect to maximum distances between localities (P = 0.003)] than ‘old’ species. Synanthropic species are excluded. A year later the authors (Hamilton et al. 201 1) corrected their numbers, resulting in an even more disillusioning 86%- 89% of undescribed species (almost identical numbers are reported in Mora et al. 2011). The numbers presented above for Pholcidae suggest that in groups with ‘active' taxonomists (see below) it may take much less than hundreds of years. At the current rate of about 570 species per decade it may take no more than 40-60 years to ‘complete’ a global total of 4,000- 5,000 pholcid species. Taking into account the predicted difficulties in finding the ever rarer species and aiming for the majority reduces the time necessary to an encouraging 10- 20 years. What do I mean by ‘active’ taxonomists? Available estimates of the numbers of taxonomists worldwide (6,000-47,000; Wilson 2004; Haas & Hauser 2005; Costello et al. 2013b) and species described per year (8,000-18,000, depending on the number of synonyms; Wheeler et al. 2012; Costello et al. 2013a; Mora et al. 2013) suggest an average of only about 0. 2-3.0 newly described species per taxonomist per year. Taxonomy of course is not only about describing new species, and I am not questioning the overall scientific productivity of taxonomists (about a fifth of taxonomists work on the relatively well-known tetrapods: Gaston & May 1992). However, the numbers suggest that only a small fraction of taxonomists actually invest a considerable amount of time in species descriptions (cf. Evenhuis 2007; Bebber et al. 2013). The fact that 20% of all spiders newly described in the last decade belong to just two of the currently 112 families (Oonopidae and Pholcidae: see Platnick 2013) illustrates the point for this particular group. On a broad scale we will probably never get even close to the 100 species per taxonomist and year envisioned by Wheeler et al. (2012). However, the number is realistic in individual cases counting on the support staff proposed by these authors. Supporting such ‘active’ taxonomists may be among the most promising approaches against the taxonomic impediment (cf. Bebber et al. 2013; Sluys 2013). In all the above, the involvement of several factors, each of which is estimated or predicted with error, obviously results in rough orders of magnitude rather than precise numbers. Technical advances that may increase rates of description are as difficult to predict as future changes in the conceptual framework (e.g., allowing for intraspecific genitalic variation may drastically decrease species numbers in many arthropod groups). Numbers of synonyms and cryptic species are equally difficult to estimate, and may affect the time necessary to reach whatever level of completeness we aim at (e.g., Bickford et al. 2007; de Carvalho et al. 2013). Another possibly confounding factor is the distributional range of undescribed species. On average, widespread species are likely to be discovered and described sooner than local endemics (e.g., Agnarsson et al. 2013; Essl et al. 2013), and Fig. 6 illustrates this point for the Atlantic Forest data on Pholcidae. This non-linear relationship between described and undescribed species means that the method used above may underestimate true species richness. Extinction, on the other hand, may ironically help taxonomists reach the goal sooner than expected. Estimates of extinction rates vary mostly between about 1 % and 10% per decade (Stork 1997; Costello et al. 2013a; Mora et al. 2013). Since forest loss is probably the single major factor driving current extinctions (Stork 1997) and Pholcidae are most diverse in pristine forests and have a high percentage of locally endemic species (e.g., Huber 201 1, 2013; see also Fig. 6), their rate of extinction is probably at the higher rather than the lower end. Although the effect is relatively moderate at 1% per decade (about 200-250 species less in 50 years, assuming 4,000-5,000 current species), it is quite significant at 10% (about 1,600-2,000 species less in 50 years). Although it may be hard to see a realistic chance to stop the ongoing extinction 146 THE JOURNAL OF ARACHNOLOGY in the near future, I am optimistic that a concentrated focus on manageable tasks and a renewed effort by trained taxonomists to actually describe species can get taxonomy very far in a very reasonable period of time. ACKNOWLEDGMENTS 1 am most grateful to the many people who assisted in expeditions and helped with permits and logistics: A. Perez Gonzalez, C. Rheims, A. Giupponi, J. Ricetti and M. Alves Dias (Brazil); A. Perez Gonzalez and A. Capella (Dominican Republic); E. Monsanto and B. Wisner (Haiti); L Agnarsson, G. Binford and A. Sanchez (Cuba); R. Duncan and M. Sidibe (Guinea); P. Kwapong and J. Bosumtwe (Ghana); P. LeGall. R. Kamga and F.J. Muafor (Cameroon); J. Mavoungou and R. Ango Nkomo (Gabon); G. Eilu and A. Kushemererwa (Uganda); C. Warui and R. Mwakodi (Kenya). I thank I. Agnarsson and G. 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The Journal of Arachnology 42:148-154 Discovery of two new species of eyeless spiders within a single Hispaniola cave Trevor Bloom 1 , Greta Binford 1 , Lauren A. Esposito 2 , Giraldo Alayon Garcia 3 , Ian Peterson 1 , Alex Nishida 1 , Katy Loubet- Senear 1 and Ingi Agnarsson 4 - 5 : ‘Department of Biology, Lewis and Clark College, Portland, Oregon, USA; 2 Esssig Museum of Entomology and Environmental Science Policy and Management, University of California, Berkeley, California, USA; 3 Museo Nacional de Historia Natural, La Habana, Cuba; department of Biology, University of Vermont, Burlington, Vermont, USA Abstract. Vision is a remarkable sensory adaptation; however, natural selection may not favor maintenance of eye function in habitats where eyesight does not contribute to fitness. Vision loss is relatively common in cave-dwelling spiders in the temperate zone, but appears rarer in tropical caves. To date, blind spiders in the (sub)tropical Caribbean have only been described from Cuba and Jamaica, including four pholcids, a barychelid, a ctenid, and a prodidomid with reduced eyes. In our survey of over 40 caves in the Greater Antilles, mainly Puerto Rico, Isla Mona, Cuba, and Dominican Republic, we have not previously found any eyeless spiders. Here we summarize information on blind Caribbean spiders, and describe two newly discovered species representing two families, from a single cave, Cueva Seibo, in the Dominican Republic. These are the eyeless Ciba seibo n. gen., n. sp. (Ctenidae) and the vestigial-eyed Trichopelma maddeni n. sp. ( Barychelidae). Cueva Seibo appears to be an energy-poor system with a relatively small bat population and is physiologically unique amongst caves we surveyed. We postulate that troglobiomorphism in the Caribbean may result from individual cave environments and hypothesize convergent eye loss within this cave, as most members of both families, including epigean species from the Dominican Republic, have normal eyes. However, another blind species, Ciba cahada (Alayon 1985) n. comb., occurs in a cave in Cuba and it remains to be tested if eye loss occurred in these two convergently, or if their shared lack of eyes is homologous. Keywords: Blind spiders, Barychelidae, Caribbean, Ctenidae, troglomorphic, tropical caves Caves are distinct terrestrial ecosystems in receiving little or no light from the sun. As primary production through photosynthesis is limited, cave systems are supported by energy that enters from outside, such as plant and animal debris, rendering many cave ecosystems energy poor and supported by decomposers (Culver 2000; Cardoso 2012). Caves are thus useful model systems to study adaptation in response to low energy input (Klaus et al. 2013; Niemiller & Zigler 2013). ‘Cave adaptations’, or troglobiomorphisms, include regressive and constructive traits, as a response to permanent darkness, low food and local conditions (Cardoso 2012; Trontelj et al. 2012). In some cases, direct selection can drive energy-saving strategies such as non-expression of eyes and pigments (Klaus et al. 2013; Niemiller & Zigler 2013). Natural selection can also result in other cave adaptations such as increased life spans and development times, elongation of appendages, and increased non-optic sensory perception (Arnedo 2007; Porter 2007; Klaus et al. 2013; Niemiller & Zigler 2013). Historically, the study of cave-adapted organisms was focused on temperate ecosystems, where it was hypothesized that the evolution of obligate cave dwellers was related to glaciation periods in the Pleistocene, a time during which tropical regions may have been less affected (Barr 1967; Sbordoni 1982, 2000; Barr & Holsinger 1985; Holsinger 1988). Countless examples of temperate, troglobiomorphic animal lineages exist (Culver 2000; Porter 2007). Although the impact of glaciation periods on cave fauna in the tropics is difficult to evaluate, many tropical caves differ starkly from temperate caves in being energy-rich ecosystems (Mitchell 1969; Ferreira et al. 1998; Bishop et al. 2012). They may contain huge 5 Corresponding author. Email: iagnarsson@gmail.com. populations of bats, often numbering in thousands or hundreds of thousands, and these systems are driven by the massive influx of energy through bat guano (Ferreira et al. 1998; Pellegrini et al. 2013). Thus animal densities, including decomposers and their predators, can be very high. In such systems, selection for energy-saving traits may be less intense. This seems an intuitively satisfying explanation of why cave adaptations are less frequent in the tropics, but to properly address that question comparative analyses of a range of tropical and temperate cave systems are necessary. As top invertebrate predators, arachnids are one of the most important and common groups in cave environments. In temperate zones about 20-25% of spiders found in caves are troglobitic (Gertsch 1973a, 1973b; Peck 1990, 1999; Garcia 2000; Culver & Pipan 2009; Trajano & Bichuette 2009; Griswold et al. 2012; Jager 2012; Miller & Rahmadi 2012), expressing the traditional troglobiomorphic adaptations such as loss of eyes, reduction of pigmentation and elongation of appendages (Culver & Pipan 2009; Niemiller & Zigler 2013). The reduction and absence of eyes is a more frequent condition than other external sensory reductions in spiders (Jimenez & Llinas 2009). In many spider families visual sensory perception is not critical for prey capture, courtship, or mating, with obvious exceptions including families such as Salticidae and Lycosidae. To date there are approximately 1 000 described species of eyeless spiders, representing close to 60 families. Not all of these are cave dwellers, but among blind cave species, well over 90% are described from the temperate zone (Gertsch 1973a, 1973b; Peck 1990, 1999; Garcia 2000; Culver & Pipan 2009; Trajano & Bichuette 2009; Griswold et al. 2012; Jager 2012; Miller & Rahmadi 2012). A small number, as far as we can tell less than 30 species, of eyeless troglobiotic spiders are known from the tropics (Culver & 148 BLOOM ET AL. — NEW BLIND CARIBBEAN CAVE SPIDERS Figure 1. — CarBio team inside the second chamber of Cueva Seibo, Parque Nacional del Este, Provincia de Altagracia, Republica Dominicana (18.35536°N, 68.61825°W), July 10, 2012. This is the type locality for eyeless Ciba seibo sp. nov. and the vestigial-eyed Trichopelma maddeni sp. nov., which were found under large limestone slabs shown here. Inset maps show the location of Cueva Seibo. Pipan 2009). These include species from Hawaiian lava tubes, which are extremely long, shallow, dark and isolated environments (Gertsch 1973b; Howarth 1993), Asian and Australasian caves (jager 2012; Miller & Rahmadi 2012), and Neotropical caves including Cuba, Jamaica, the Galapagos, and Mexico (Gertsch 1973a; Peck 1990, 1999; Garcia 2000; Trajano & Bichuette 2009). Although the caverniculous fauna of the Caribbean islands is certainly understudied, current evidence suggests that only a small percentage of Caribbean caves contain blind organisms (Peck 1999). Here we describe two new species of troglobitic spiders, in two different families, found in Cueva Seibo within Parque Nacional Del Este in the southeast corner of the Dominican Republic. The former, a completely eyeless ctenid, we place in a new genus, Ciba seibo n. gen., n. sp., which also contains a blind species from a cave in Cuba. The latter, a Barychelidae species retaining vestigial eyes, belongs to the new species Trichopelma maddeni n. sp. These are the first eyeless spiders to be described from Hispaniola, adding to a very short list of seven additional blind spiders from the Caribbean. Given that most lineages found in explored caves do not have reduced eye function, we speculate on what unique aspects of this cave system may explain the occurrence of two lineages indepen- dently converging on the reduction of eyes. METHODS Specimens were collected in Cueva Seibo (Fig. 1) in Parque Nacional Del Este, Dominican Republic. Approximately ten researchers of our team first descended into the multi-room cave in July 2012. After discovering the first eyeless spiders among the specimens collected, a smaller team returned to target these animals specifically. All Ciba and Trichopelma specimens, including one adult of each and several juveniles, were found under Hat limestone slabs lying on top of other 149 larger stones in the second and completely dark chamber of the cave (Fig. 1). During collection, Ciba specimens remained motionless with legs bent in a way similar to Loxosceles, which were common throughout the cave but retained their common morphology of six eyes. Specimens were preserved in 95% ethanol and rough sorted to morphospecies in the field. Using a Visionary Digital BK Plus digital imaging system, we took standard taxonomic photographs of adult females (Figs. 2, 3). The limited availability of adult specimens — one female of each species — and the fragility of the genitalia, especially of the barychelid, hampered their detailed dissection and illustration and limited the taxonomic utility of the photographs. Therefore, we also extracted DNA and amplified sequences of Cytochrome Oxidase 1 (CO I) (for extraction methods and primers see Agnarsson & Rayor 2013, Agnarsson et al. 2013b, Kuntner et al. 2013) to provide further diagnostic characters through DNA barcodes. These barcodes could also aid in determining the family placement of these species. We blasted the sequences against sequences in GenBank and BOLD; howev- er, Genbank turned out to have too limited DNA barcode data available to help identification of these species (Garston et al. 2013a). In BOLD the Ciba specimen has the highest blast hit with an unidentified Ctenidae (90.1 percent identity), supporting its placement in this family. However, there are no public records of Barychelidae in BOLD, and the closest blast hit was with a Theraphosidae species (85.5% Poecilotheria miranda) in this case not allowing precise family placement based on barcodes alone. TAXONOMY Family Ctenidae Keyserling 1877 Subfamily Cteninae Keyserling 1877 Ciba n. gen. Justification. — We describe the new genus Ciba based on unique features of the female genitalia, including absence of basal and median epigynal spurs and form of spennathecae and copulatory ducts that differ clearly from other Ctenidae genera. The two included species both occur in caves with no known epigean relatives. Given the poor knowledge of Caribbean spiders we hypothesize that epigean Ciba species are yet to be discovered, a taxonomic hypothesis that will require testing through further sampling of specimens and phylogenetic analyses. Type species . — Ctenus calzada Alayon 1985. Designated here. Etymology. — The specific name is an arahuac word meaning big rock. The gender is feminine. Diagnosis. — Females resemble those of genera Ctenus and Ohvida by the general features of the epigyne, but can be distinguished from these two genera by the absence of basal and median epigynal spurs. Description. — Median size ecribellate spiders (Fig. 2). Total body lengths (females); 7. 9-9.0 mm. Carapace prolonged and anterior truncated; thoracic groove longitudinal. Ocular area 1/5 of the cephalic region; eyeless or with six small eyes (in three files of two). Chilum inconspicuous. Clypeus with few bristles or no bristles at all. Chelicerae with scattered white setae in frontal area and margins; promargin with three teeth; 150 THE JOURNAL OF ARACHNOLOGY Figure 2. — Female hololype Ciba seibo sp. nov. a) dorsal habitus; b) ventral habitus; c) lateral habitus; d) dorsal carapace, note absence of eyes; e) external epigynum; f) internal epigynum dorsal, CD=copulatory duct, S=spermathecae; g) internal epigynum ventral, OMP=oval median plate. DNA barcode is displayed below illustrations. retromargin with four-five large and regularly spaced teeth and a small denticle. Endites convergent and with internal lateral margins excavated, distally semi-rounded bearing dense apical scapulae and setae. Sternum oval, not extending between coxae IV. Leg formulae 4312 or 4231. Trochanters notched. Abdomen oval with filiform setae in the anterior dorsal area. Epigyne (Figs 2e— g): subtriangular with projected and sclerotized lateral margins; lateral spurs absent. Internal genitalia: with very short and curved copulatory ducts emerging from basal area of spermathecae. Composition. — Two species: Ciba calzada and C. seibo n. sp Distribution. — Cuba and Hispaniola. Ciba calzada (Alayon 1985) n. comb. Ctenus calzada Alayon, 1985:3^1, Fig. 1 (female holotype from Sistema Cavernario Majagua Cantera, Cueva de las Dos Anas, Sierra de San Carlos, Luis Lazo, Municipio Matahainbre, Provincia de Pinar del Rio, Cuba, deposited in the MNHNCu, examined). Diagnosis. -Females can be distinguished from Ciba seibo sp. nov. by the weakly sclerotized marginal area of the epigynum and the presence of six reduced eyes. Description. -Aftf/e. Unknown. Female (holotype). Total length (mm) 9.00. Carapace 4.20 long. 3.40 wide. Abdomen 4.80 long, 2.80 wide. Labium 0.70 long. Sternum 1.95 long, 1.80 wide. Leg measurements: I, femur 6.30, tibia 6.90; II, femur 6.60, tibia, 6.30; III, femur 6.80, tibia 6.90; IV, femur 7.30, tibia 7.20. Leg formulae 4312. Leg spination: tibia I and II ventral 2-2-2-2-2 (shorts), dorsal 1-1, prolateral 1-1; metatarsus I and II ventral 2-2-2; tibia III and IV ventral 2-2, dorsal 1-1, prolateral 1-1; metatarsus III and IV ventral 1-1-1, dorsal 1-1, prolateral 1-1. Epigyne: sub-triangular, lateral margins weakly sclerotized, head of spermathecae rounded. Additional material examined. — Two females (paratypes) from the type locality. Distribution. Only known from the type locality. Natural history. — Found in crevices on the floor, under rocks, and low parts of the walls of the cave. Ciba seibo Alayon and Agnarsson n. sp. (Figs. 2a-g) Type material. -Female holotype from Cueva Seibo, Parque Nacional del Este, Altagracia province, Dominican Republic (18. 35536°N, 68.61 825°W), July 10, 2012, Col. Team CarBio, deposited in the NMNH Smithsonian. Etymology. -The species name is a toponym in apposition referring to the type locality. Diagnosis. -The females of Ciba seibo sp. nov. resemble those of C. calzada by the morphology of the epigynum, but can be distinguished by the most heavily sclerotized margins of BLOOM ET AL.— NEW BLIND CARIBBEAN CAVE SPIDERS 151 e 1 mm 0.5 mm Figure 3. — Female holotype Trichopelma maddeni sp. nov. a) dorsal habitus; b) ventral habitus; c) lateral habitus; d) dorsal carapace, note small white vestigial eyes; e) external epigynum; f) internal epigynum dorsal; g) internal epigynum ventral. DNA barcode is displayed below illustrations. the epigynum, the low position of the spermathecae, and the presence of two small ‘eye spots’, or vestigial eyes. Description. — Male unknown. Female (holotype). — Total length (mm) 7.97. Carapace 4.33 length and 3.28 wide. Sternum 1.88 long and 1.88 wide. Labium 0.91 long and 0.79 wide. Leg measurements: I femur, 4.09; tibia 5.37; II femur 5.48; tibia 5.57; III femur 4.77; tibia 4.76; IV femur 5.91; tibia 6.27. Leg formulae 4231. Leg spination: tibia I and II ventral 2-2-2-2-2 (shorts), no dorsal or prolateral spines; metatarsus I and II ventral 2-2-2; tibia III and IV with an irregular pattern of 6-7 spines both ventrally and dorsally; metatarsus III and IV with an irregular pattern of 5-7 spines both ventrally and dorsally. Epigyne: median plate sub-cuadrate, margins curved and sclerotized. Additional material examined. — Only known from holotype female and several juveniles from the type locality. Distribution. — Only known from the type locality. Natural history. — Found on cave floor under stones in the dark area of the cave. Barcode. — partial barcode, positions 18-658 of the standard barcode: TTGGACTTGACCAGCTTAASCAGGTACGGG GATAAGAGTTTTAATTCGTATAGAATTAGGTCATTC T GGT AGATT GTTAGGGG ATG ATC ATTT GT AT AATAG TT GTTGTT ACTGCT CAT GCTTTT GT A ATG ATTTTTTT TATGGTAATACCAATTTTAATTGGTGGATTTGGTAA TTGGTT AGTT CCTTT A AT ATT AGGGGCT C CTG AT AT A TCGTTTCCTCGTATAAATAATTTATCTTTTTGATTGT TGCCACCTTCTTTATTTTTGTTGTTGATATCTTCTAT 152 THE JOURNAL OF ARACHNOLOGY GGTGGAAATAGGGGTTGGGACTGGTTGAACTGTTT AT CCTCCTTT AGCTT CT AG A ATTGGTC AT AT AGGT A G ATC A AT GG ATTTTGCT ATTTTTT CTTT AC ATTTAGC TGGGGCTTCTTCTATTATAGGGGCGGTAAATTTTAT TTCTACT ATTGTT A ATAT AC GTTT ATT AGGG AT A AG A AT AGAG AGGGT GCCTTT GTTT GTTT GGT CGGTTTTT ATT AC AGCT ATTTT ATT GTT ATT GTCTTT ACCT GTGT T AGCGGGT GCT ATT ACT AT ATT GTT G ACT GAT CGA A ATTTTAATACTTCTTTCTTTGATCCTGCGGGAGGAG GAGATCCTGTTTTATTTCAACATTTGTTT. Family Barychelidae Simon 1889 Trichopelma imuUleni Esposito and Agnarsson n. sp. (Figs. 3a-g) Type material. — Female holotype from Cueva Seibo, Parque Nacional del Este. Altagracia province, Dominican Republic (18.35536 N, 68.61825°W), July 10, 2012, Col. Team CarBio, deposited in the NMNH Smithsonian. Etymology. — A noun in apposition, named in honor of the Caribbean naturalist Hannah Madden. Diagnosis. — The female of Trichopelma maddeni n. sp. is the First blind species in this genus and is therefore readily diagnosed from other congeners. The transverse pallid weak- ness (suture) of tarsus IV, characteristic of the genus, is present. The only other species recorded from Hispaniola is known from a single, fully eyed, male specimen ( Trichopelma nitida Simon 1888), so a meaningful comparison cannot be made. Description. - Female (holotype). Light brown coloration of carapace and chelicerae, abdomen greyish-tan, legs light brown with the exception of the conspicuously greyish-tan femur. Covered entirely in fine, acuminate setae, ventral surfaces of the cephalothorax are covered in additional coarse macrosetae. A cluster of macrosetae present at the center of the ocular area, as is a line of 12 macrosetae, slightly anterior to the ocular cluster, on the anteromedian margin of the carapace (Fig. 3d). The tibia and metatarsus of legs I and II each with six spines; femur through metatarsus of legs III and IV covered with numerous elongate spines. Paired tarsal claws with single denticular row. Chelicerae without conspicuous rastellum, and single row of teeth on the cheliceral promargin. Ocular area nearly flat, eyes absent with slightly lighter pigmentation at the sites of absent eyes (Fig. 3d). Thoracic furrow transverse and straight. Labium subquadrate with — 100 cuspules on the anterior third. Total length (mm) 159. Carapace length 66.8, width 53.8. Sternum length 30.4, width 26.8. Labium length 10.0, width 10.2. Leg measurements: 1 femur 64.4, tibia 60.6; II femur 53.1, tibia 53.8; III femur 55.0, tibia 48.8; IV femur 74.4, tibia 69.4. Leg formulae 4123. Spermathecae width 12.5, divided into two capitated regions (Fig. 3f, g). Male. Unknown. Additional material examined. — Only known from holotype female and several juveniles from the type locality. Distribution. -Only known from the type locality. Natural history. — Collected from the dark zone of a limestone cave under stones on the cave floor. Barcode, partial barcode, positions 38-658 of the standard barcode; GTAGGAACTGCTATAAGAGTTGTTATTCGTATTG AGTTGGGACAAGTTGGAAGATTATTAGGTGATGAT C ATTT AT AT A AT GT GGT GGT A ACGGCTC AT GCT CTT GT GAT G ATTTTTTTT ATAGTA AT ACCT ATTTT A ATT G G AGG ATTTGGG A ATT GA AT GTT ACCTTT A AT ATT AG G AGCTCCT GAT AT AGCTTTT CCGCGAAT G A AT A ATT T GAG ATTTT GGTT ATT ACCT C CTT CTTT ATTTTT GTT GATTTTATCTTCTTTGACTGATGTTGGTGTAGGAGC TGGATGGACAATTTACCCCCCCTTATCATCTTTTATT GGACACTCAGGTGGTGGAATGGATTTCGCTATTTTT TCTTTACATTTGGCTGGTGCTTCGTCTATTATGGGAT CTATTAATTTTATTACTACAGTAATAAATATACGGG GCATAGGAATAAAGTTGGAGCGAGTTCCTTTGTTT GTCTGGT CGGTTGTT ATT AC A ACT GTTTT GCTTTT A CTTTCCTTGCCTGTGTTGGCTGGTGCAATTACTATA TT GTT GTTT G ATCGT A ATTTT A ATACCT CTTTTTTT G ATCCTGCGGGTGGGGGTGATCCTATTTTGTTTCAA CATTTATTT. PREVIOUSLY DESCRIBED TROGLOMORPHIC CARIBBEAN SPIDERS Barychelidae. — Troglothele coeca (Fage 1929) - Cuba. This was the first troglomorphic mygalomorph found in Cuba, and the Caribbean. Only two juvenile females have been collected in the type locality, Cuevas de Bellamar, Matanzas, in northwest Cuba near Havana. Lack of genitalic and genetic material hinders comparison and speculation on possible relationship with T. maddeni. Pholcidae. — Anopsicas cubanus (Gertsch 1981) - Cuba. This species, only known from a male, is the only blind pholcid in Cuba, type locality Cueva Grande, Punta Caguanes, Yagua- jay, de Sancti Spiritus Province. Anopsicas claims Gertsch 1982 - Jamaica. Known only from a female, type locality Caves of Clarendon Parish. Anopsicas jarmila Gertsch 1982 - Jamaica. Known only from a female, type locality Worthy Park, Cave No. 2, St. Catherine Parish. Anopsicas nebulosus Gertsch 1982 - Jamaica. Known only from a female, type locality Duanwary, Cave No. 1, St. Elizabeth Parish. Ctenidae. -Ciba calzada (Alayon 1985) new combination - Cuba. Ciba calzada is described from the Majagua-Cantera cave system as well as Cueva de Las Dos Anas and Sierra de San Carlos, all in the province of de Pinar del Rio in western Cuba. The species is only known from females, which have six highly reduced eyes. At least an additional two eyeless ctenids have been described from Australia: Janusia muiri (Gray 1973) and Amauropelma undarra (Raven et al. 2001). Prodidomidae. — Lygromma gertschi (Platnick & Shadab 1976) - Jamaica. Lygromma gertschi is the only known troglobitic gnaphosid. Its troglomorphisms include the loss of functional eyes, elongation of the legs, tarsal trichobothria, and spinnerets, and the loss of teeth on the tarsal claw. Male and female holotypes were described from Falling Cave, Douglas Castle, St. Ann Parish, northern Jamaica. RESULTS AND DISCUSSION We describe two new blind spider species, from two spider families, discovered in a single karst cave in southeast Dominican Republic. Ciba seibo lacks eyes altogether, while T. maddeni retains vestigial eyes. This discovery is significant for several reasons. First, there are few troglobitic spiders in BLOOM ET AL.— NEW BLIND CARIBBEAN CAVE SPIDERS the region, with only seven previously described blind cave species, four from Jamaica and three from Cuba (Platnick 1976; Gertsch 1982; Peck 1999; Alayon 2000). Second, no cave explored to date has contained more than a single blind species. Third, of all the caves explored in the karst regions of the Greater Antilles islands to date, only a small fraction contain any troglobiomorphic animals (Peck 1999; Alayon 2000; Garcia 2000), certainly much less than 20-25%. Therefore, in the tropics, the occurrence of troglobiomorph- ism appears to be caused by a set of conditions unique to a single cave rather than a regional pattern. That Cueva Seibo contains two blind spider species while most hitherto explored Caribbean caves harbor no blind spiders is likely the result of a combination of factors including cave age, energy input into the cave, and historical characteristics of the cave, such as openings to the surface. It is unlikely that cave age alone explains the evolution of troglobiomorphic traits, as karst caves typically are of similar age across a karst region, and the morphology of a cave, such as the depth, darkness, and connectivity to the outside environment is not directly related to the age of the karst development (Jones & Smith 1988). Strikingly, molecular genetic estimates of divergence indicate that significant eye reduction can occur in as little as one hundred years in cave-dwelling invertebrates (Caccone & Sbordoni 2001; Arnedo et al. 2007). Hawaiian lava tubes, for example, much younger than Caribbean karst formations, contain blind spiders (Gertsch 1973; Gray 1973; Clarke 2010). Troglobitic spiders have been hypothesized to adapt to particular ecological niches within a cave, determined by a number of physical factors such as light availability, stability, humidity, percentage of C0 2 and the amount of available nutrients (Arnedo et al. 2007). The relatively small and localized population of bats, and relatively low abundance of decom- posing animals (pers. obs.) suggests that Cueva Seibo may be a low energy system due to the low import of external nutrients via guano. The large limestone slabs on the cave floor indicate a recent collapse of the cave roof at the only known entrance to the cave. We hypothesize that historically this was a largely closed cave with insufficient surface connections to allow significant use by bats, and that troglobiomorphism evolved during this period of extremely low energy input. CONCLUSIONS The finding of two eyeless spider species T. maddeni and C. seibo in a single cave is unique in light of the paucity of troglobiomorphic spiders in the Caribbean. Although troglo- biomorphisms occur ubiquitously in temperate region caves, the evolution of troglobites in the tropics may be influenced by characteristics of individual caves such as morphology and energy input. Troglobitic species express a high degree of endemism; often species are restricted to individual caves (Cardoso 2012; Niemiller & Zigler 2013). Further morphological and phylogenetic comparison of subterranean and surface populations of related spider species will advance our under- standing of factors such as speciation, ecological adaptation and morphological change that generate subterranean biodiversity. ACKNOWLEDGMENTS Many thanks to Dominican Republic arachnologists Lie. Gabriel Santos and Solanlly Carrero Jimenez for their 153 invaluable help in collection and identification of DR arachnids, and to the entire CarBio team for their relentless effort. Permits were obtained with the help of Kelvin Guerrero through the Secretaria de Estado de Medio Ambienle y Recursos Naturales and research was facilitated by the Direccion General de Parques Nacional (The National Park Service of the Dominican Republic), and its park rangers. We especially thank the park ranger stationed at the east entrance of Parque Nacional Del Este who helped us locate and navigate Cueva Seibo. We are grateful to Miquel Arnedo, Matjaz Kuntner, and an anonymous reviewer for comments that improved the manuscript. Financial support came from the National Science Foundation (DEB- 13 14749, DEB- 1050187, DEB-1050253) to IA and GB and ( DBI- 1 003087) to LE, University of Vermont, University of California Berkeley, University of Puerto Rico, Lewis and Clark College and the John S. 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E-mail: anacarolineovasconcelos@gmail.com; 2 Laboratorio de Referenda Nacional em Vetores das Riquetsioses, LIRN- FIOCRUZ, Manguinhos, Rio de Janeiro-RJ, CEP 21040-360, Brazil; Laboratorio de Aracnologia, Museu Nacional, Universidade Federal do Rio de Janeiro, Quinta da Boa Vista s/n, Sao Cristovao, Rio de Janeiro-RJ, CEP 20940-040, Brazil Abstract. A new species of the genus Charinus Simon 1892 from the state of Minas Gerais, Brazil, is described. Charinus jihaossu sp. n. is morphologically close to C. mysticus Giupponi & Kury 2002 and shows both a marked secondary sexual dimorphism in the pedipalps and an interesting polymorphism in the spines of the distitarsus. The new species is endangered because it inhabits a region highly impacted by mining activities. Keywords: Caves, neotropics, taxonomy, whip spiders Amblypygi is an order of Arachnida distributed in tropical and subtropical ecosystems and comprises five families, 17 genera, and 164 living species, as well as nine described fossil species (Harvey 2003, 2013; Zhang 2013). The greatest diversity of Amblypygi occurs in the Neotropical region, which has about 100 described species (Harvey 2013). These species are represented in the Neotropics by the genera Charinus Simon 1892 of the family Charinidae, Acanthophrynus Kraepelin 1899, Heterophrynus Pocock 1894, Pamphrynus Moreno 1940, and Phrynus Lamarck 1801 belonging to the family Phrynidae, and Trichodamon Mello-Leitao 1935 belonging to the family Phrynichidae. With the exception of Charinus and Phrynus, these genera occur exclusively in the New World (Harvey 2002, 2003, 2013). Although Phrynus is mostly restricted to the Americas, one species inhabits Indonesia (Harvey 2002). Charinus has approximately 50 species distributed worldwide mostly in tropical and subtropical regions (Weygoldt 2000; Jocque & Giupponi 2012). In Brazil, ten species have been described for the genus, which are located in the northern region of the country: C. vulgaris Miranda & Giupponi 2011; Northeast: C. potiguar Vasconcelos et al. 2013, C. acaraje Pinto-da-Rocha et al. 2002, C. mysticus Giupponi & Kury 2002, and C. troglohius Baptista & Giupponi 2002; and Southeast: C. asturius Pinto-da-Rocha et al. 2002, C. hrasilianus Weygoldt 1972, C. montanus Weygoldt 1972, C. e/eonorae Baptista & Giupponi 2003, and C. schirchii (Mello-Leitao 1931), whose type has been lost and thus is considered to be a nomen dubium (Pinto-da-Rocha et al. 2002). Herein we describe a new species of Charinus from caves of the speleological province of Arcos/Pains/Doresopolis (Minas Gerais, Brazil), one of the most important karst areas of the country. We also comment on the remarkable sexual dimorphism of the species. METHODS The specimens were collected through visual searching of the floors and walls throughout the caves. All specimens were captured with a fine brush and placed in vials containing 70% ethanol. For nomenclature and measurements, we generally followed the proposals of Quintero (1981). The names of the gonopod structures of males followed Giupponi & Kury (2013). The article called tarsus by Quintero (1981) is divided here into the distitarsus and claw, as there is no fusion of these two segments in Charinidae. The spines of the pedipalpal tibia and teeth of the chelicerae are counted from the apex to the base. Measurements of the articles of the pedipalp were taken between the condyles of each segment in order to establish fixed points and adequate length measurements. We took measurements of the entire type series (quantity indicated as “n”), presenting first their mean values, followed by the range of variation in parentheses. Illustrations of the genitalia were made through a camera lucida coupled to a Leica MDLS phase contrast microscope. We prepared other illustrations using a camera lucida attached to a Nikon SMZ-10 stereomicroscope. Photographs were made using a Leica M205A stereomicroscope with the software Leica Application Suite Automontage. To make Scanning Electron Microscope images, we dried the genitalia by transfer through an alcohol series (70%, 80%, 90%, and 100%) and submitted them to critical point drying. After that, the genitalia were placed on stubs, sputter coated and viewed in a JEOL-JSM-6390-LV scanning electron microscope. The holotype and paratypes were deposited in the Museu Nacional, Rio de Janeiro, Brazil (MNRJ), and paratypes in the Seqao de Invertebrados Subterraneos, Collection of Zoology of the Universidade Federal de Lavras, Minas Gerais, Brazil (ISLA), in the Museu de Zoologia da Universidade de Sao Paulo (MZUP) and Wingless Arthropods Vectors of Impor- tance in Comunities’ Health Collection (CAVAISC), Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil. Additional material examined. — Charinus acaraje'. 4 females: Brazil, Bahia, Gruta Pedra do Sino, Santa Luzia (ISLA 3843, ISLA 3844, ISLA 3845, ISLA 3846); 1 female: Brazil. Bahia, Gruta Lapao de Santa Luzia (new record), Santa Luzia (ISLA 3840). Charinus vulgaris: Female holotype: Brazil, Rondonia, Porto Velho, Bairros Sao Joao Bosco, Rio Madeira and Santo Antonio (MNRJ 09106). 155 156 THE JOURNAL OF ARACHNOLOGY Charinus bromeliaea Jocque & Giupponi 2012: Female holotype, French Guyana, Savanna Roche La Virginie (MNRJ 09185). Charinus potiguar : Male holotype: Brazil, Rio Grande do Norte, Felipe Guerra, Caverna do Buraco Redondo (MNRJ 09216). Charinus mysticus : Female holotype: Brazil, Bahia, Caverna Encantados, Gentil do Ouro (MNRJ 9074), 16 km from Santo Inacio, road to Gameleira (cave with stream, about 8 m from entrance). TAXONOMY Family Charinidae Quintero 1986 Genus Charinus Simon 1892 Charinus Simon 1892:48. Full synonymy: see Harvey (2013). Type species. — Phrynus australianus L. Koch 1867, by original designation. Diagnosis. -Charinus jihaossu differs from other species of the genus by having the frontal process longer than wide with a pointed apex; median and lateral eyes developed; claw of the chelicera with 12 denticles (10 can be found); sexual dimor- phism in the pedipalps; pedipalpal femur with 6 dorsal spines (5 can be found) and 6 ventral (5 can be found in females), tibia with 7 dorsal spines (6 can be found) and 4 ventral (3 can be found), and distitarsus with polymorphism in the spines; leg femur lengths: I > III > II > IV; body length up to 16 mm; male gonopod with lobus dorsalis in shape of a large claw; edges of the female gonopods with a small fold and a bottleneck below these. Charinus jihaossu new species (Figs. 1-21) Type material.- Male holotype: BRAZIL: Minas Gerais: Gruta da Cazanga (20°17'06.58"S, 45°35'47.45"W), Arcos, 11 June 2011. R.L. Ferreira (MNRJ 09257). Paratypes: BRAZIL: Minas Gerais : 1 3, same data as holotype (ISLA 3835); 1 3, same data as holotype except 3 1 January 2009. R.A. Zampaulo (MNRJ 09258); 1 la > lb = II > III. Claw with 12 denticles (10 can be found), the basal ones being wider. Strong setae distally on dorsum of the cheliceral body. Pedipalp (Figs. 5-12): Trochanter: Ventral spiniform apophysis pointed forwards with a series of strong setiferous tubercles. Two spines of subequal size aligned on the prolateral face, the first being near of the medial region and the second above the projection of the apophysis and near the femur. Three setae aligned between the spines and 2 basal to the first spine. Dorsal oblique series of strong setae. Femur: Strong dorsal setae. Three large setiferous tubercles dorsal (2 can be found) and some smaller in the basal region. Wide variation in the amount and position of reduced spines. Primary dorsal series with 6 spines (5 can be found) decreasing in size, with the spine I located after the basal tubercles. Secondary dorsal series with up to 3 reduced spines between the primary. Primary ventral series with 6 spines (5 can be found in females) of sizes: FI > FII > AI = Fill > FIV > FV in males and FI > FII > Fill > AI = FIV > FV in females. Secondary ventral series with up to 6 reduced spines between VASCONCELOS ET AL— NEW SPECIES OF CHARINUS FROM BRAZIL 157 Figures 1-8 . — Charinus jibaossu new species: 1. Carapace (female paratype); 2. Frontal process (holotype); 3. Sternum (holotype); 4. Teeth and denticles of the left chelicera (male paratype); 5. Ventral view of the right pedipalp (holotype); 6. Dorsal view of the right pedipalp (holotype); 7. Ventral view of the right pedipalp (female paratype); 8. Dorsal view of the right pedipalp (female paratype). the primary series of spines in the male and 3 in the females. Tibia: Strong dorsal setae. Seven dorsal spines (6 can be found) of sizes: 1 >2>3>AI>4>5>6; the last two are reduced. Strong ventral setae located distally. 3 ventral spines on distal half in descending order of size, with a basal one very reduced (can be absent). Basitarsus (Figs. 11, 12): Strong dorsal setae. Two dorsal spines, the II being approximately twice as large as I. One strong ventral setiferous tubercle on the basal portion. One ventral spine in the distal half of size slightly smaller than the dorsal spine I. Distitarsus (Figs. 11, 158 THE JOURNAL OF ARACHNOLOGY Figures 9-16 . — Charinus jibaossu new species: 9. Trochanter, femur, and tibia of the right pedipalp (holotype); Scale bar = 2 mm; 10. Trochanter, femur, and tibia of the right pedipalp (female paratype); Scale bar = 2 mm; 1 1. Dorsal view of the right basitarsus, distitarsus, and tarsal claw of the pedipalp (holotype), the first spine is indicated; Scale bar = 1 mm; 12. Dorsal view of the right basitarsus, distitarsus, and tarsal claw of the pedipalp (female paratype); Scale bar = 1 mm; 13. Arrangement of trichobothria on the last segment of the basitibia and on the distitibia of right leg IV (holotype); Scale bar = 2 mm; 14. Dorsal view of the genitalia (male paratype); Scale bar = 500 pm; 15. Ventral view of the genitalia (male paratype); Scale bar - 500 pm; 16. Dorsal view of gonopods (female paratype); Scale bar = 500 pm. The following abbreviations are used: Fi = fistula (gonopod tube). LoD = lobus dorsalis, LoLl = lobus lateralis primus, and LoL2 = lobus lateralis secundus. VASCONCELOS ET AL NEW SPECIES OF CHARINUS FROM BRAZIL 159 Figures 17-19 . — Charinus jibaossu new species: 17. Gonopod of female in dorsal view; 18. Gonopod of female in side view; 19. Gonopod of male in ventral view. 12): Several strong dorsal setae and long ventral setae. Wide variation in the number of spines. Three or 2 spines ( 1 or 4 can be found) dorsal of the cleaning organ in ascending order of size. Cleaning organ occupies about half of the length of article. Claw (Figs. 11, 12); Long with sharp curved tip. Legs: All densely setose. Femur lengths: I > 111 > II > IV. Leg I: Tibia with 23 articles and tarsus (basitarsus+distitarsus) with 41 articles. Leg IV (Fig. 13): Basitibia with 4 pseudo- articles and 1 medial trichobothrium on the last article. Distitibia with 3 basal and 15 distal trichobothria; frontal and caudal series with 6 trichobothria each. Basitibia-distitibia length: BTI > DT > BT4 > BT3 > BT2. Ratio distitarsus/ basitarsus approximately 5/6. Distitarsus composed of 4 segments. Color. Live specimens exhibit a pattern of grayish brown coloration (Figs. 20B, 20D). In alcohol (Figs. 1-8): Adult males with intense reddish brown coloration on the carapace, pedipalps, and chelicerae, with legs slightly lighter. Abdomen grayish dorsally and yellowish ventrally. Dark spots can be observed in larger specimens on the dorsum of the chelicera. A clear round spot is found on the dorsum of the coxae of the pedipalps of the two larger males. Females and smaller specimens have a pattern of more yellowish coloration on the carapace, pedipalps, chelicerae, legs, and sometimes on the abdomen. Genitalia : Male (Figs. 14, 15, 19): Margin of genital operculum rounded with a few scattered setae. Genitalia rounded, with short longitudinal splitting. Fistula (gonopod tube) exceeds the genital operculum margin. Sclerotized band in each side of the ventral portion of fistula. Lobus dorsalis claw-like protruding from each side of fistula, with a slight sclerotization at its apex and curved to one another. Lobus lateralis secundos emerges from fistula in the sides of lobus dorsalis. Lobus lateralis primus emerges in the sides of the lobus lateralis secundos (Fig. 19). Lamina medialis and processus interims emerge ventral to fistula in two pair of triangular projections, lamina medialis smaller, claw-shaped and sclerotized, and processus interims wider and lamellar. Female (Fig. 16-18): Genital operculum margin rounded with several strong setae. Gonopods sucker-like, cone shaped, and longer than wide. Gonopod openings rounded, edges with a small fold and a bottleneck below these. Gonopods separated from one another approximately by the diameter of each structure and distant from the margin of the operculum by a distance near its length. Scleroses in central sides of the bases, and between the middle area and the apex of each gonopod. Natural history and threats. — The specimens examined for this study came from collections taken from caves located in the karst province of Arcos/Pains/Doresopolis in Minas Gerais state (Fig. 20A). All collection localities are from a limestone formation called “Bambui” group, dating from the late upper Proterozoic (Aider et al. 2001). According to the Koppen climatic classification, the area is Cwa (warm temperate clime - mesotermic) with rainy summers and dry winters. Its average annual precipitation is around 1,350 mm, concentrated mainly between the months of December and February, and the annual temperature average is 20.7°C. Although the karst area of Arcos/Pains/Doresopolis is large and includes hundreds of caves, Charinus jibaossu is restricted 160 THE JOURNAL OF ARACHNOLOGY Figure 20. A. Location of karstic province of Arcos/Pains/Doresopolis in the state of Minas Gerais, Brazil; B. Female of Charinus jibaossu inside the cave; C. Caves where Charinus jibaossu was found and surrounding areas with mining activities; D. Male of Charinus jibaossu inside the cave; E. Limestone formation. to a small area in the northern portion of this province in the Arcos municipality. More than 400 caves were sampled in the entire province, but specimens of C. jiboassu were found only in 1 1 caves (Fig. 20C). Furthermore, the numbers in each cave were usually low (1-2 individuals), which might indicate that (i) the population densities are very low in each cave or, conversely, (ii) the caves are not the main habitat of the species, and only part of the population sheltered within caves. Specimens were usually found on the cave walls, and potential prey includes young crickets (Endecous sp. and Eidmanacris sp.), moths, and roaches that were also frequently seen in the caves where C. jibaossu specimens were observed. VASCONCELOS ET AL.— NEW SPECIES OF CHARINUS FROM BRAZIL 161 Factor 1 Morphometric measures FI F2 Cephalotorax length -0.680 -0.733 Cephalothorax width -0.944 0.111 Length of the femur of the pedipalp -0.969 0.200 Length of the tibia of the pedipalp -0.967 0.207 % variance 80.7 15.8 Figure 21. — Principal Component Analysis (PCA) of morphomet- ric measurements for analysis of sexual dimorphism of the Charinus jibaossu. Larger and medium circles = males; smaller circles = females. An important aspect of the species habitat is that the caves where C. jibaossu were found are mostly dry caves, in contrast to the moist caves where most Brazilian species of Charinus normally live. The external area where the species occur has been altered over time by human activities, especially by cattle ranching and limestone exploitation (Fig. 20C). Fortunately, the original forests still persist in areas unsuitable for agriculture or livestock due to the limestone outcrops (Fig. 20E). Such forests may be found to support populations of C. jibaossu , or at least provide organic resources for the caves. However, the mining activities are mainly focused on those outcrops so that the species certainly can be considered endangered. Sexual dimorphism of Charinus jibaossu . — A Principal Components Analysis (PCA) was performed using the matrix of covariance of the log-transformed variables (cephalothorax length and width , and pedipalpal femur and tibia length), a usual procedure in analyses of morphological patterns in populations and communities (Manly 1986). The procedures of the Principal Components Analysis (PCA) reduced the four morphological measurements to two axes (Fig. 21). The variables width of the cephalothorax and lengths of the pedipalpal femur and tibia of the pedipalps were important in the first factor, which explained 80.7% of the variance observed among individuals. The lengths of the femur followed by the tibia were the most important variables in Factor 1 (Fig. 21). Accordingly, we detected an evident sexual dimorphism for such traits in C. jibaossu. In males, the pedipalpal femur has an average length of 9.14 mm, and the pedipalpal tibia an average of 10.01 mm (Table 1). While in the females, the pedipalpal femur has an average length of 3.94 mm, and the pedipalpal tibia an average of 4.56 mm (Table 1). Weygoldt (2000) commented that as long as they are used for fighting, the Table 1. — Measurements (mm) of selected body parts of the specimens of Charinus jibaossu new species. Males (n = 11) Females (n = 12) Total length 13.02 (9.05-16.00) 12.06 (9.88-12.73) Cephalothorax Length 4.68 (3.67-5.48) 4.10 (3.00-6.23) Width 6.05 (5.08-6.80) 5.24 (4.48-6.38) Pedipalp Femur 9.14 (3.96-14.24) 3.94 (2.59-5.28) Tibia 10.01 (4.81-15.52) 4.56 (3.29-6.48) Basitarsus 2.06 (1.53-2.62) 1.69 (1.27-2.25) Distitarsus 1.43 (1.03-1.87) 1.27 (0.97-1.97) Tarsal claw 0.95 (0.61-1.22) 0.97 (0.62-1.32) elongated pedipalps of the male might confer selective advantages. Gross (1996) also argued that in most cases these types of alternative phenotypes are conditioned by a reproductive strategy favored in evolution. The cephalothorax width also explained morphometric differences between males and females. The average carapace width of males was 6.05 mm, and in females was 5.24 mm (Table 1). However, although such measurements have shown a separation between adult males and females in later developmental stages, this is not a characteristic that separates them clearly. The PCA revealed four males with measurements similar to those observed in females. The specimens probably include recently matured adults that still do not have the full growth of their pedipalps as these increase allometrically in relation to the rest of the body parts such as carapace length (Weygoldt 2000). DISCUSSION Charinus jibaossu is the eleventh species of the genus described from Brazil and the second from the state of Minas Gerais. Charinus jibaossu differs from other Brazilian species in a number of characteristics, but particularly in body size. Along with C. mysdcus, this group comprises the largest species in Brazil so far. According to Weygoldt (2000), the species of Charinus have a body length of up to 1 5 mm; however, some males of C. jibaossu exceed this value (Table 1). The pedipalps of C. jibaossu , as already mentioned, display distinctive sexual dimorphism (Figs. 20B, C), being extremely elongated in males, which make them even more robust when compared with other species of Charinus. Sexual dimorphism is present in some species of Amblypygi (Weygoldt 2000). Among the species of the genus in Brazil, C. asturius, C. brasilianus , and C. montanus , also from the southeast region, exhibit sexual dimorphism in the pedipalps, but in C. jibaossu this is more pronounced. Charinus jibaossu has similarities to other species of Brazil, such as C. mysdcus, a species from the state of Bahia. The pattern of spines on the pedipalp and setae on the sternum of C. jibaossu is comparable to that observed in C. mysdcus. Both species have the pedipalpal femur and tibia with a similar numbers of spines and the tritosternum with many strong setae. The spines of these pedipalpal segments and tritoster- num setae were difficult to describe in general, as they vary widely. Since the pedipalps of C. jibaossu males lengthen after sexual maturity, the number of secondary spines can also increase (Weygoldt 2000). The presence of only three spines in 162 THE JOURNAL OF ARACHNOLOGY the pedipalpal distitarsus also occurs only in these two species from Brazil. Giupponi & Kury (2002) were the first to establish the presence of a third distitarsus spine in the pedipalp in C. mysticus. Weygoldt (2005) verified the presence of the third spine in C. madagascariensis Fage 1954 and C. dhofarensis Weygoldt et al. 2002, suggesting they were related species, but without commenting on the existence of three spines in C. mysticus. Charinus jibaossu has this third accessory spine in the basal portion of the distitarsus of the pedipalps; however, an unprecedented variability of this character is verified. In one of the females, two spines were observed on the right pedipalp and only one on the left, while in a male, three spines on the left and four on the right. In some males, setiferous tubercles were observed positioned exactly in the same place as the third spine, indicating that they could become spines in larger individuals. Males with two spines and females with three were also observed, showing that the polymorphism is probably related to the size of the specimens. Other similarities are found between C. jibaossu and C. eleonorae. These two species have the frontal process with a pointed apex, and a similar number of cheliceral denticles. Weygoldt (2005, 2006, 2008) divided the Charinus species into three groups based on the morphology of the female gonopods: (i) group of C. bengalensis species, characterized by thin “finger-like” gonopods; (ii) the group of C. brasilianus species, characterized by “sucker-like” gonopods; and (iii) a group of C. australianus species, wherein the gonopods are Battened “cushion-like” structures. The gonopod of C. jibaossu corresponds to the C. brasilianus type, a group that includes most of the Brazilian species. Females of C. jibaossu have an opening with a small fold and a bottleneck located below this (Figs. 16-18). This type of morphology is also seen in C. potiguar and C. mysticus ; however, the gonopod of C. jibaossu is thinner. The genitalia of the male C. jibaossu has its secundus lobus lateralis claw-shaped (Figs. 14, 15), similar to that seen in the illustrations of C. montanus , C. asturius and C. acaraje (Weygoldt 1972; Pinto-da Rocha et al. 2002), yet it is markedly larger. The genital organ is rounded as in C. acaraje , but it has a much less pronounced longitudinal division than that of this species. Although C. jibaossu apparently does not comprise a troglobitic species, its restricted distribution makes it highly vulnerable. In 2008, the Brazilian legislation that had formerly granted full protection to caves was amended (Decree-law n° 99,556 to Decree-law n° 6,640), so that caves are now susceptible to damage or destruction by various human activities such as mining. As for C. jibaossu, the evident alterations observed throughout its range, especially the expansion of mining activities, further raise the risks to this species. ACKNOWLEDGMENTS We thank Dr. Paulo Reis Rebelles (EPAMIG-CTSM/ EcoCentro Lavras) for allowing us the use of the microscope with camera lucida and CAPES - edital Pro-equipamento 2010 for the auto-montage equipment. The SEM micrographs were taken in the SEM Lab of Marine Diversity of the MNRJ (financed by PETROBRAS), with the kind assistance of Amanda Veiga and Plataforma de Microscopia Eletronica Rudolf Barth, Fundagao Oswaldo Cruz, IOC. This study was supported by “Conselho Nacional do Desenvolvimento Cientifico e Tecnologico” and Fundagao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG Process No. APQ 01826-08 and Process CRA - PPM-00433-1 1) and CNPq (grant 301061/201 1-4 to RLF). LITERATURE CITED Auler, A., E. Rubiolli & R. Brandi. 2001. As grandes cavernas do Brasil. Gritpo Bambui de Pesquisas Espeleologicas. Giupponi, A.P.L. & A.B. Kury. 2002. A new species of Charinus from northeastern Brazil. Boletim do Museu Nacional 477:1-7. Giupponi, A.P.L. & A.B. Kury. 2013. Two new species of Heterophrynus Pocock, 1894 from Colombia with distribution notes and a new synonymy (Arachnida: Amblypygy: Phrynidae). Zootaxa 2:329-342. Gross, M.R. 1996. Alternative reproductive strategies and tactics: diversity within sexes. Trends in Ecology and Evolution 1 1:92-98. Harvey, M.S. 2002. The first Old World species of Phrynidae (Amblypygi): Phrynus exsul from Indonesia. Journal of Arachnol- ogy 30:470-474. ’ Harvey, M.S. 2003. Catalogue of the Smaller Arachnid Orders of the World: Amblypygi, Uropygi, Schizomida, Palpigradi, Ricinulei and Solifugae. CSIRO Publishing, Collingwood, Victoria, Aus- tralia. Harvey, M.S. 2013. Whip Spiders of the World, version 1.0. Western Australian Museum, Perth. Accessed 28 April 2014, online at http://museum.wa.gov.au/catalogues/whip-spiders Jocque, M. & A.P.L. Giupponi. 2012. Charinus bromeliaea sp. n. (Amblypygi: Charinidae); a new species of bromeliad inhabiting whip spider from French Guyana. Zootaxa 3158:53-59. Manly, B.F.J. 1986. Multivariate Statistical Methods: A Primer. Chapman and Hall, London. Pinto-da-Rocha, R., G. Machado & P. Weygoldt. 2002. Two new species of Charinus Simon 1 892 from Brazil with biological notes (Arachnida; Amblypygi: Charinidae). Journal of Natural History 36:107-118. Quintero, D.J. 1981. The amblypygid Phrynus in the Americas (Amblypygi, Phrynidae). Journal of Arachnology 9:117-166. Weygoldt, P. 1972. Charontidae (Amblypygi) aus Brasilien. Zoolo- gische Jahrbiicher, Abteilung fur Systematik, Okologie und Geographic der Tiere, Jena 99:107-132. Weygoldt, P. 2000. Whip Spiders: Their Biology, Morphology and Systematics. Apollo Books, Stenstrup, Denmark. Weygoldt, P. 2005. Biogeography, systematic position, and repro- duction of Charinus ioanniticus (Kritscher, 1959) with the description of a new species from Pakistan (Chelicerata, Ambly- pygi, Charinidae). Senckenbergiana Biologica 85:1-14. Weygoldt, P. 2006. Courtship and sperm transfer in Charinus neocaledonicus Kraepelin, 1895 and Charinus australianus (L. Koch, 1867) (Arachnida, Amblypygi, Charinidae). Zoologischer Anzeiger 244:239-247. Weygoldt, P. 2008. Spermatophores, female genitalia, and courtship behaviour of two whip spider species, Charinus africanus and Damon tibialis (Chelicerata: Amblypygi). Zoologischer Anzeiger 247:223-232. Zhang, Z. 2013. Phylum Arthropoda. Zootaxa 3703:17-26. Manuscript received 17 January 2014. revised 20 May 2014. 2014. The Journal of Arachnology 42:163-169 Scorpion diversity of the Central Andes in Argentina F. Fernandez Campon, S. Lagos Silnik and L. A. Fedeli: Laboratorio de Entomologia, 1ADIZA - CONICET, CCT Mendoza, Av. Ruiz Leal s/n, Parque Oral. San Martin, Mendoza (5500), Argentina. E-mail: fcampon@mendoza-conicet.gov.ar Abstract. Mountain habitats host a large number of endemic species, which are vulnerable to climate change. We studied scorpion communities of the Central Andes in Argentina at 17 sites located in Andean and extra-Andean areas between 900 and 3400 m elevation. Using pitfall traps, we collected 254 individuals from seven species, all from the Bothriuridae family. Although we expected a decrease in richness towards the high altitude sites, we did not find a clear pattern. In turn, the lowest site was the most diverse and rich; other sites had similar richness values regardless of altitude. High-altitude sites were characterized by the presence of Orobothriurus Maury 1975 species. Orobothriurus alticola (Pocock 1899) has been found exclusively on Andean sites located above 3200 m, and O. grismadoi Ojanguren-Affilastro et al. 2009 has only been found at extra-Andean sites on Cerro Nevado. Community composition showed an association with altitude, with some species exclusive to high altitude sites and others only found at lower sites. Because of the ecological importance of scorpions in arid environments, this study provides base information that may help design conservation actions for these habitats. In particular, the presence of high-altitude specialists like Orobothriurus species seems relevant, since they may be used as bioindicator species. Keywords: Altitude, mountains, community, species richness Approximately one fourth of the Earth’s surface is covered with mountains. Mountain habitats support a third of the plant diversity (and probably a similar proportion of animal species) and supply half of the drinking water for human populations (Korner 2007). Given the particular conditions of climate and isolation prevailing in mountains, these habitats can be hotspots of diversity (Lomolino 2001; Prendini & Bird 2008) and usually host a large number of endemic species (Prendini & Bird 2008; Flores & Pizarro-Araya 2006; Roig- Junent et al. 2008). Altitude is a variable that is frequently related to changes in species richness and community composition (Brown 1995). However, altitude per se does not necessarily have an effect on species distribution. Environmental variables that change with altitude may have an effect on community composition. Mountain areas are characterized by a decrease in richness and abundance as altitude increases (e.g., Prendini & Bird 2008; Munyai & Foord 2012; Salas-Morales & Meave 2012), though the highest richness and abundance might not be found at the lowest but at intermediate altitudes (Lomolino 2001; Munyai & Foord 2012). The Central Andes in Argentina comprise the arid part of the Andes range. Within this area of the Andes we can find different biomes associated with differences in altitude, soil and history, which in turn cause differences in species richness and biodiversity and high levels of endemism (Flores & Pizarro- Araya 2004; Augusto et al. 2006; Ochoa et al. 2011). This is particularly true for some groups adapted to arid conditions, such as insects (Tenebrionidae: Coleoptera), which are very rich and diverse in this part of the Andes (Flores & Pizarro-Araya 2004; Flores & Gomez 2005). These Andean habitats are also important water reservoirs; snowpacks accumulated in the mountains are the main source of rivers that water the lowlands (Masiokas et al. 2006). In addition, altitude makes these habitats very susceptible to global climate changes and intense exploitation of natural resources (e.g., mining). An increase in global temperature will cause high-altitude habitats to shrink their area, with the possibility of local extinction of species adapted to these types of habitats. Despite its relevance for diversity conservation, there is little knowledge of the arthro- pod fauna of this area. Thus, a first step towards conservation of the area and its wildlife is to know the composition and distribution pattern of its communities. Among arthropods, scorpions are important due to their abundance in arid regions. Recent studies suggest that, in certain arid areas of the world, scorpions are the major group of predators in terms of density, biomass and diversity (Polis 1990). Being generalist predators, they have a fundamental role in the structure of communities (Polis 1990). Although scorpions have been reported to occur in high- altitude regions up to 4900 m (Ochoa et al. 2011), no community studies have been conducted for these habitats in South America. Added to the fact that high-altitude species are more at risk under a climate change scenario, this highlights the importance of such studies in high-altitude areas. The aim of our study was to describe the scorpion community in mountain habitats of the Central Andes and analyze its composition in relation to environmental variables associated with altitude. METHODS Study area. — The study was carried out at 17 sites within an area that includes Andean as well as extra-Andean sites (i.e., Cerro Nevado) (Table 1). Sites located at different altitudes contain different habitat types (Fig. 1, Table 1 ). The Monte is characterized by shrubby vegetation dominated by creosote bush (Larrea divaricata and L. cuneifolia). The pre-Puna or “cardonal” extends onto the hillsides and canyons and supports many of the species of the Monte plus some endemic grasses, cacti and legumes. The Puna lies above 2800 m elevation and is characterized by a dry shrubby steppe with small shrub species not exceeding 40-150 cm. High-altitude grasslands occur at 1900-2500 m and are dominated by species such as Stipa tenuissima that occupy large areas called 163 164 THE JOURNAL OF ARACHNOLOGY Table 1. — Location and description of the study sites. Altitude is an average of the four altitudes registered in each sampling period. Site Code Altitude (m.a.s.l.) Habitat type Villavicencio (Road 52) N1 1000 Monte Villavicencio N2 1700 Prepuna Paramillos N3 2850 Puna Pampa Canota N4 2800 Altitude grassland Estancia Tambillos N5 2400 Monte Puntas de Vacas N6 2400 2nd altoandino Horcones N7 2900 2nd altoandino Las Cuevas N8 3200 2nd altoandino Alvarado (Northen slope) SI 2300 2nd altoandino Alvarado (Southern slope) S2 2300 2nd altoandino Pampa de los Avestruces S3 3570 3rd altoandino Reserva Laguna del Diamante S4 3350 2nd altoandino Laguna del Diamante S5 3300 2nd altoandino Cerro Nevado Nel 2350 Patagonian steppe Cerro Nevado Ne2 2600 2nd altoandino Cerro Nevado Ne3 2950 2nd altoandino Cerro Nevado Ne4 3100 3rd altoandino “pampas”. Andean highlands (Altoandina region) are char- acterized by low-growing plants and large areas of bare soil. The vegetation layer is dominated by shrubs of the genus Adesmia (Cabrera 1971). Sampling design.- - We sampled scorpions for two consecu- tive years during the austral spring and summer (December 2004 and February 2005, January 2005 and February 2006), which is the time of the year when epigean arthropods are active at all sites. We set up two altitudinal transects running up the Andes range (north transect: sites N1-N8 and south transect: sites S1-S5; at 33° and 35° S latitude respectively). Sites along the transects were selected in order to have representatives of those habitat types found in mountain areas at these latitudes. In addition, a third extra-Andean transect was sampled from the base up to the summit of Cerro Nevado mountain (sites Nel-Ne4; Fig. 1) to examine historical differences of the Andes range. Each transect followed an altitudinal gradient including different habitat types. At each site, we randomly set up eight 1 X 1 m quadrats with a pitfall trap at each corner and left them at the site for 10 days. For data analysis the four traps in each quadrat were pooled. Pitfall traps were plastic cups of 10 cm diameter filled with 100 ml of a 20% propylene glycol solution. Keeping the same sampling techniques in all sites (pitfall traps) enabled us to compare sites in terms of abundance. Scorpions were identified using the keys to genera and species by Ojanguren-Affilastro (2005) and a reference collection provided by the same author. Collected specimens were preserved in 70% ethanol and, after identification, were deposited in the permanent Arachnology Collection at the Instituto Argentino de Investigaciones de las Zonas Aridas (IADIZA - CONICET, CAI). Statistical analyses. -To explore the relationship between species and environmental variables, a Canonical Correspon- dence Analysis (CCA) was applied to data from sampling sites. Data on species density and environmental variables were transformed by applying In (x+1). Explanatory variables included in the models were related to temperature and precipitation, and were obtained from WorldClim version 1.4 (Hijmans et al. 2005). The spatial resolution of the climatic data is 30 s (approximately 1 km 2 ). Thus, the values are the same for all quadrats within a locality at each sampling period. Variables related to productivity (NDVI) were obtained from NASA (NASA 2001, online at http://lpdaac. usgs.gov/get_data). These variables are shown in Appendix 1. Prior to the CCA, Spearman correlation analysis was performed among environmental variables to test whether there was a high level of correlation between them. Variables showing a correlation P > 0.60 were excluded from the analysis. CCA was performed using the analytical software MVSP version 3. 1 . RESULTS We collected 254 individuals (north: 116; south: 103; extra- Andean: 35), all belonging to the Bothriuridae family. No scorpions were caught in pitfall traps at sites N3 and S5. Thus, these sites were excluded from the analyses. The most abundant genus (38%) was Orobothriurus Maury 1975, followed by Brachistosternus (Pocock 1893) (29%), then Bothriurus Peters 1861 (22%) with only one species (B. burmeisteri Kraepelin 1894), and Timogenes Simon 1880 (11%). At the specific level, the most abundant species were Orobothriurus alticola (Pocock 1899) (28%), most abundant at sites located above 3000 m elevation, and Brachistosternus weijenberghi (Thorell 1876) (27%) (Table 2). They were followed by Bothriurus burmeisteri , a species present on most of the sites (22%), Orobothriurus grismadoi Ojanguren-Affilastro et al. 2009 (10%), Timogenes elegans (Mello-Leitao 1931) (7%), and 71 haplochirus Maury & Roig Alsina 1977 (4%) [the last two species were only found at the lower Monte site (N 1 )], and Brachistosternus montanus Roig Alsina 1977 (2%). Diversity and evenness were higher at N 1 and N6 and were zero at sites with only one species present, such as N8 and S4 with O. alticola, and SI with Bothriurus burmeisteri (Table 2) In the CCA, the first two axes explained 69.36% of the cumulative variance, suggesting a good relationship between species distribution and the environmental variables consid- ered. Figure 2 shows the distribution of the sites and species within the environmental space delimited by axes 1 and 2. Variables that significantly positively correlated with FERNANDEZ CAMPON ET AL. -SCORPIONS OF THE CENTRAL ANDES 165 Figure 1. Maps of Mendoza province (top) indicating the locations of the study sites within transects, and of South America (bottom) showing the location of Mendoza province. environmental axis 1 (/• > 0.50) were isothermality and precipitation in the coldest quarter (snow) of the year, whereas seasonality in temperature and average annual productivity were negatively correlated with this axis. The variables that correlated positively with axis 2 were seasonality in temper- ature and precipitation in the warmest quarter (rain), whereas precipitation in the coldest quarter and isothermality showed a negative correlation with this axis. In Fig. 2 we can identify four groups of species. Two of these groups include one of the two species of Orobothriurus. Both species of Orobothriurus are found at high altitudes (above 2300 m in Cerro Nevado and above 3200 m in the Andes). However, the sites where they were recorded appear in different parts of the environmental space. In fact, all sites on Cerro Nevado (Nel-4) form a distinct group clustering around O. grismadoi. From Fig. 2 we can see that these sites are less thermally stable than those at the cordillera (S3 and S4) and receive less snow during the winter as well. The third group in the plot includes both Timogenes species. These are only found at site N1 (Table 2). This site is within the Monte desert biome and based on the environmental space of the plot in Fig. 2, it has high rainfall during the warmest quarter, it is thermally seasonal and has high minimum temperatures during the coldest month compared to the other sites. Finally, in the fourth group Brachistosternus and Bothriurus species were present at most locations. They appear in the center of the environmental space, probably indicating their widespread distribution at the study sites. The plot of altitudinal range reinforces results from previous analyses (Fig. 3). It shows the presence of altitude specialists with a narrow altitudinal range at high altitude (both Orobothriurus species) and at low altitude ( Timogenes species). In addition, there are some generalists such as Bothriurus sp. and Brachistosternus weijenberghi with a wide altitudinal range. DISCUSSION Despite the importance of mountain areas due to their sensitivity to climate changes and their biodiversity value (e.g., endemisms), there are few studies on scorpion communities in these types of habitats (Prendini & Bird 2008). Without taking into account sites of very high scorpion richness and abundance, such as Baja California Peninsula, Mexico (Jimenez-Jimenez & Palacios-Cardiel 2010), and several sites in southern Africa (e.g., Prendini & Bird 2008), richness values found in our study are similar to those obtained for other arid regions of South America. Augusto et al. (2006) reported nine species (maximum richness of three at a site) in a study involving a latitudinal transect in Chile; Acosta (1995) found nine sympatric species in Chancani (Cordoba, Argentina); and Ochoa (2005) reported 24 species in his study area covering a mosaic of biomes in the Peruvian Andes, and a highest richness of six in some dry habitats (Lomas, Serrania esteparia, Queswa). Comparing community composition of scorpions in our study with that of other studies in South America such as Ochoa’s study (2005) of the Andes of Peru, we find certain differences in dominance of the genera found. Although Ochoa (2005) presents data on species occurrence and not on abundance, it is possible to make some comparisons. Within his study area, almost 80% of the species (/? = 19) belonged to the family Bothriuridae and among those, Brachistosternus was the most dominant genus with 10 species present in all habitats except in the Yungas (the only mesic habitat found in his study). Among them, three species of Brachistosternus occur in a narrow altitudinal belt at high altitude (above 2900 m). In our study, Br. montanus belongs to this group (Andean group in Ojanguren-Affilastro & Ramirez 2009) but 166 THE JOURNAL OF ARACHNOLOGY Table 2. — Species frequencies and ecological indices estimated for the study sites. Bh: Bothriurus burmeisteri, Bnv : Brachistosternus weijenberghi, Brnv.Bmchistosternus montanus\ Te: Timogenes elegans ; 77;: Timogenes haplochirus\ Oa: Orobothriurus altieolci ; Og: Orobothriurus grismadoi. In parentheses we show the abundance of females plus juveniles and males. Females and juveniles are shown together because they could not be distinguished according to Ojanguren-Affilastro (2005). Site Bh Bnv Ban Te Th Oa Og Total abundance Relative abundance Shannon's index Evenness Nl 7 (L6) 21 (16,5) 0 18 (4,14) 9 (9,0) 0 0 55 0.22 1.29 0.54 N2 4 (2,2) 3 (3,0) 0 0 0 0 0 7 0.03 0.68 0.28 N3 0 0 0 0 0 0 0 0 0.00 0.00 0.00 N4 1 (0,1) 1 (0,1) 0 0 0 0 0 2 0.01 0.69 0.29 N5 2(1,1) 36 (30,6) 0 0 0 0 0 38 0.15 0.21 0.29 N6 1 (1,0) 4 (4,0) 2 (2,0) 0 0 0 0 7 0.03 0.96 0.04 N7 3 (2,1) 3 (3,0) 0 0 0 0 0 6 0.02 0.69 0.29 N8 0 0 0 0 0 1 (1, 0) 0 1 0.00 0.00 0.00 SI 13 (12,1) 0 0 0 0 0 0 13 0.05 0.00 0.00 S2 14 (4,10) 0 3 (0,3) 0 0 0 0 17 0.07 0.47 0.19 S3 1 (1,0) 2 (2,0) 0 0 0 17 (10,7) 0 20 0.08 0.52 0.22 S4 0 0 0 0 0 53 (4,49) 0 53 0.21 0.00 0.00 S5 0 0 0 0 0 0 0 0 0.00 0.00 0.00 Nel 5 (1,4) 0 0 0 0 0 5 (3,2) 10 0.04 0.69 0.29 Ne2 1 (1,0) 0 0 0 0 0 1 (1.0) 2 0.01 0.33 0.14 Ne3 1 (0,1) 0 0 0 0 0 9 (2,7) 10 0.04 0.54 0.22 Ne4 3 (2,1) 0 0 0 0 0 10 (7,3) 13 0.05 0.69 0.29 we found it in very low abundances. It is the Orobothriurus species that seems to mostly occupy the highest altitudinal sites in our study. In Ochoa’s study, Orobothriurus was the second most important genus with six species. Orobothriurus occurred at all sites with the highest richness (six). However, no more than one species of Orobothriurus occurred at any one particular site. In our study we also found only one species of Orobothriurus in the sites where the genus occurs, but they were only present at high altitude sites (Table 2). Orobo- thriurus grismadoi seems to be a habitat specialist found only in Altoandina vegetation of this mountain. The narrow distribution area of O. grismadoi (only in Cerro Nevado) is probably due to historical factors that isolated it from other mountain areas where related species of Orobothriurus occur (Ochoa et al. 201 1). This makes O. grismadoi very vulnerable under a climate change scenario, with an increase in temperature leading to a potential shrinkage of suitable habitat. In fact, Cerro Nevado is known to have other endemic species of high-altitude arthropods (e.g., carabid beetles, Roig-Junent et al. 2008), with closely related species found at high-altitude locations in the Andes range (Roig- Junent et al. 2007). Most species of the genus Orobothriurus are found primarily in high-altitude habitats (over 2000-2500 m, with a maximum recorded at 4190 m) from Central Peru to Argentina (Mattoni et al. 2012). With the exception of O. alticola , which is found in the Andes range, the remaining three species of Orobo- thriurus from Argentina ( O. compagnucci Ochoa et al. 2011; O. famatina Acosta & Ochoa 2001; O. calchaqui Ochoa et al. 2011) exhibit a narrow distribution and have been recorded so far only at their type localities in extra-Andean mountains (Ochoa et al. 2011). The second most important genus in abundance following Orobothriurus was Brachistosternus. This genus showed high abundances at lower sites, but specifically at those sites belonging to the Monte habitat. This happened at both the lower Monte (Nl, 1000 m) as well as in the high-altitude Monte (N5, 2400 m), suggesting that despite differences in environmental conditions between these two sites, certain characteristics of the Monte habitat are suitable for the species. All described species of Brachistosternus are known from arid and semi-arid regions in South America, from southern Patagonia to central Ecuador. Within the subgenus Brachistosternus there are two monophyletic groups: Andean and Plains groups (Ojanguren-Affilastro & Ramirez 2009). In our study, Br. weijenberghi (Plains group) was much more abundant than Br. montanus, which was found in very low abundances along both the northern and southern transects and in sympatry with Bothriurus burmeisteri (N6 and S2) and Br. weijenberghi (N6). Finally, the third most important genus was Bothriurus. Although this is one of the most diverse genera within Bothriuridae (Ojanguren-Affilastro 2005), it was only represented by a single species, B. burmeisteri. This species has a widespread distribution in Argentina from the central part of the country to the southern tip in Patagonia, and probably also in Tierra del Fuego, inhabiting the phytogeographic areas of Monte, Patagonia and Espinal (Ojanguren-Affilastro 2005). Based on the pattern of abundance of these genera, it seems that there is a change in dominance depending on altitude (and habitat type): while at high sites (Altoandina region) Orobothriurus dominates, Brachistosternus is the most domi- nant genus at lower sites, at least in the Monte habitat. This does not mirror the altitudinal range pattern of the species (Fig. 3). Although Br. weijenberghi has high abundances at lower sites, it also occurs in low abundance even at our highest site (S3). Orobothriurus , on the other hand, have a range restricted to high-altitude sites. This is the first study on scorpion communities from the South American Andes inhabiting a vulnerable area under threat from climate change. Because of the ecological importance of scorpions in arid environments (Polis 1990), this study provides base information that will serve to monitor these habitats. In particular, the presence of high-altitude FERNANDEZ CAMPON ET AL— SCORPIONS OF THE CENTRAL ANDES 167 CM to Og V 23 - Ne3 A 1.7- Ne2A A Ne4 Net* 1 1-1- Bb S4^ Oa Th N1 ▲ v Te N2^ N5 A V Brw N4 ^S5 N6 Brm A S3 1.9 XZ 2 5 S2 N8 -2.3—*— Axis 1 Figure 2. — CCA plot of species and sites (a) and environmental variables (b). Refer to Table 2 for species abbreviations and to Appendix 1 for abbreviations of environmental variables. specialists, such as species of the genus Orobothriurus, seems to be relevant as they would be suitable for this purpose. ACKOWLEDGMENTS We want to thank Dr. Andres Ojanguren-Affilastro (MACN) for providing us with a reference collection and Dr. Rodolfo Carrara (IADIZA) for facilitating data on WorldClim variables for the study sites. This study was part of a larger project on arthropod diversity from mountain areas of central-west Argentina carried out by personnel from the Entomology Laboratory at IADIZA, CCT-Mendoza. Thus, work in the field and sample processing was a team effort. This study was supported by the Consejo Nacional de Investigaciones Cienti- ficas y Tecnicas (CONICET), Argentina, by a grant ot the Agencia Nacional de Promocion Cientifica y Tecnologica (ANPCYT), Argentina (“Diversidad de artropodos en am- bientes montanos del centro-oeste argentine”, PICT 01-1 1 .120). LITERATURE CITED Acosta, L.E. 1995. The scorpions of the Argentinian western Chaco. I. Diversity and distributional patterns. Biogeographica 71:49-59. Augusto, P., C.I. Mattoni, J. Pizarro-Araya, J. Cepeda-Pizarro & F. 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Salas-Morales, S.H. & J.A. Meave. 2012. Elevational patterns in the vascular flora of a highly diverse region in southern. Mexico Plant Ecology 213:1209-1220. Manuscript received 25 April 2013, revised 31 March 2014. FERNANDEZ CAMPON ET AL.- SCORPIONS OF THE CENTRAL ANDES 169 Appendix 1. — List of environmental variables included in the analysis after removal of correlated variables (see text for explanation). Environmental variable Abbreviation Mean diurnal range of temperature (mean of all the weekly diurnal temperature ranges) Isothermality (mean diurnal range (VI) divided by the annual temperature range * 100) Temperature seasonality (standard deviation of monthly mean temperature * 100) Minimum temperature of coldest month Precipitation seasonality Precipitation of warmest quarter Precipitation of coldest quarter Mean of productivity estimator Coefficient of variation of productivity estimator R_d_m Isoter Temp_est T_min_mf Pp_est Pp_qc Pp— qf Pm_ndvi Cv_ndvi 2014. The Journal of Arachnology 42:170-177 Juvenile experience and adult female mating preferences in two closely related Schizocosa species Jenai M. Rutledge 1 and George W. Uetz: Department of Biological Sciences ML0006, University of Cincinnati, Cincinnati, OH 45221-0006, USA. E-mail: george.uetz@uc.edu Abstract. Social experience is well-known to influence female mate preference in vertebrate animals, but such effects have been studied less in invertebrates. Studies have documented flexibility in female mate choice in the wolf spider genus Schizocosa as a result of juvenile female experience with courting adult males. Here we investigate whether juvenile exposure to male courtship influences adult female species-level mate recognition in the wolf spider Schizocosa ocreata (Hentz 1844) and its sympatric sibling species S. rovneri (Uetz & Dondale 1979). Because these species overlap in range, contact between them is probable as interspecies hybrids are occasionally found in nature. Juvenile females were exposed multiple times to conspecific or heterospecific male courtship. Upon maturing, each exposed female was paired with an adult male of the same or different species to which it had been previously exposed, and was observed to determine receptivity and willingness to copulate. Results suggest that juvenile experience plays only a minor role (if any) in development of female mate recognition at the level of species, because the type of juvenile experience (conspecific vs. heterospecific) did not significantly affect mating outcome for either species. However, some context-specific effects of experience were observed, because the amount of juvenile exposure to adult male courtship affected adult receptivity of females in both species in different ways. In 5. ocreata, the overall amount of juvenile experience (rather than type) influenced adult female receptivity and aggression toward heterospecific males; females with more exposures were initially more receptive and less aggressive to heterospecifics. In S. rovneri , neither type nor amount of juvenile exposure had significant effects on female receptivity towards conspecific males, although females exposed to heterospecific male courtship as juveniles were initially less receptive towards conspecific males than were unexposed females. While these results confirm earlier findings of behavioral reproductive isolation at the species level, they differ from some other studies, raising intriguing questions about varying degrees of behavioral and genetic isolation in different geographical populations of these two species. Keywords: Mate choice, social experience, sexual imprinting, behavioral plasticity, Lycosidae Recent interest in the mechanisms that lead to speciation has revealed that experience and learning can have important roles in maintaining reproductive barriers between closely related species (Panhuis et al. 2001; Mendelson & Shaw 2012). This is especially important for sympatric species where morphological and ecological divergence is minimal and/or where environments are variable (Dukas 2009; Bailey & Zuk 2009; Mendelson & Shaw 2012; Verzijden et al. 2012). Selection pressures that maintain species barriers are usually considered to be intense, as mating between species often has costly fitness consequences, such as sterile or inviable offspring and reduced reproductive output (Stratton & Uetz 1986; Maheshwari & Barbash 201 1). In many animals, evolution of species recognition mechanisms appears to have been driven by female preferences for male traits and/or courtship behaviors (Endler & Houde 1995; Wagner 1998). Mate preferences are then reinforced by fitness benefits of selectivity (mate quality) as well as fitness costs of recognition errors (hybrid incompatibility, sterility) (Pfennig 1998). However, the extent to which female preferences influence the direction of evolution of male traits (and ultimately speciation) may depend on the level of plasticity in female choice behavior (Wagner 1998; Kodric-Brown & Nicoletto 2001; Coleman et al. 2004; Uetz & Norton 2007; Mendelson & Shaw 2012; Verzijden et al. 2012). In particular, social experience during juvenile development (e.g., sexual imprinting) can influence mate preferences and result in recognition errors at adulthood 1 Current address: Arapahoe Community College, Biology Depart- ment (M3608), 5900 South Santa Fe Drive, Littleton, CO 80120-1801. (Hebets 2003; Hebets & Vink 2007; Bailey & Zuk 2009; Kozak et al. 2011). Although evidence that social experience can affect female mate preferences comes primarily from studies of vertebrate animals, behaviors of invertebrates — including mate prefer- ence — can be influenced by experience as well (e.g., Jackson & Wilcox 1993; Punzo 2000, 2004; Wagner et al. 2001; Johnson 2005; Dukas 2006, 2008, 2009; Fowler-Finn & Rodriguez 2012a, 2012b; Rodriguez et al. 2013). For example, Hebets (2003) found that adult females of the wolf spider Schizocosa uetzi Stratton 1997 mated more often with males possessing familiar phenotypes to which they were exposed as juveniles. Likewise, Hebets and Vink (2007) found that juvenile experience influences adult female mate preference for brush-legged males in a potentially interbreeding population of two wolf spider species (both brush-legged and no brushes). While these studies suggest that invertebrate mating prefer- ences may be more flexible than previously assumed, and that ‘hard-wired’, genetically-directed threshold responses to spe- cific stimuli (Parri et al. 1997; Wagner et al. 2001; Hebets 2003) can be modified with experience, other studies with related wolf spider species have suggested that mate recognition at the species level is not influenced by experience (Hebets 2007). Although speciation is most often attributed to geographic isolation, the occurrence of behavioral reproductive isolating mechanisms in closely related sympatric species suggests that behavioral barriers are sufficient to restrict gene flow and result in speciation (Stratton & Uetz 1981, 1983, 1986; but see Mendelson & Shaw 2012). However, mate choice plasticity in response to experience (especially with novel phenotypes, as in 170 RUTLEDGE & UETZ EXPERIENCE AND MATE PREFERENCE IN SCHIZOCOSA 171 the case of wolf spiders) can influence both the directionality of preference and the degree of behavioral isolation (Verzijden et al. 2012). In this study, we investigated how juvenile experience influences adult female mate recognition, using two well-studied sympatric wolf spider species within the genus Schizocosa Chamberlin 1904 (Araneae: Lycosidae). Female S. ocreata (Hentz 1844) and S. rovneri (Uetz & Dondale 1979) are morphologically indistinguishable, but male S. rovneri lack the tufts of bristles on their forelegs that are characteristic of mature male S. ocreata. Courtship displays also differ dramatically between the two species. Schizocosa ocreata male courtship is multimodal with visual (leg tapping and leg waving) and seismic components (substrate-borne vibration and/or stridulation), whereas S. rovneri male courtship is primarily unimodal and is made up of patterned seismic vibrations/stridulation only. Females distinguish between conspecific and heterospecific males on the basis of male courtship displays and male traits (Uetz & Denterlein 1979; Stratton & Uetz 1981, 1983; Uetz 2000). Males, however, court in response to female silk (and pheromones) of either species equally (Roberts & Uetz 2004). Thus, reproductive isolation is presumably maintained via female preference. On rare occasions, apparent hybrids of these two species have been collected from the field, suggesting that a breakdown in behavioral species barriers does occur, perhaps due to constraints on sensory modes (e.g., limited vibration transmission or restricted visual line-of-sight) in complex litter environments (Scheffer et al. 1996; Uetz 2000; Uetz et al. 2013). The existence of hybrids in nature may also imply that female preference/mate recognition is not entirely genetically- based, and that exposure to courting males early in the mating season (males mature earlier than females) might influence female mate choice. Recently, a mixed and presumed inter- breeding population from Mississippi was discovered, with male morphs resembling S. ocreata and S. rovneri, but with no genetic distinction between morphs (Hebets & Vink 2007; Fowler-Finn 2009). Moreover, in the Mississippi (MS) popu- lation, juvenile exposure to males increased female preference for the brush-legged morph (Hebets & Vink 2007). Because of this, the MS population, representing a phylogenetic cluster distinct from our Ohio (OH) and Kentucky (KY) populations of S. ocreata and S. rovneri (respectively), has raised questions about juvenile experience and behavioral reproductive isolation in these species. Here we test the hypothesis that sub-adult exposure to male courtship of heterospecific vs. conspecific males influences adult mate recognition by female 5. ocreata and S. rovneri from Ohio and northern Kentucky populations known to exhibit behavioral reproductive isolation (Uetz & Denterlein 1979; Stratton & Uetz 1981, 1986). METHODS Study species. — S. ocreata and S. rovneri are common ground-dwelling wolf spiders that occur in the leaf litter of deciduous forests in the eastern United States. When raised in isolation, both female S. ocreata and S. rovneri exhibit mate recognition based on species-specific male traits (secondary sexual characteristics and courtship displays). Nonetheless, it is probable that in the field, females are exposed to male courtship (of both species, where species co-occur) multiple times prior to maturity, as males begin to mature before females, occur in high densities and are engaged in near constant courtship activity in response to pheromones contained within the silk “draglines” laid down by mature females. General methods. -Studies of these two species were conducted in different years, although there is no indication from long-term studies in our lab that differences between years would affect species behavior differences. Schizocosa ocreata were collected during spring of 2005 as sub-adults from the Cincinnati Nature Center Rowe Woods (Clermont Co., OH; 39° 07'30.31" N, 84 ° 15'55.90" W) where S. rovneri do not occur. In 2009, S. rovneri were reared in the laboratory from egg sacs produced by females collected as adults from the Ohio River flood plain at Sand Run Creek (Boone Co., KY; 39 ° 06'43.75" N, 84 0 46'58.22 W) during the spring of the previous year (2008). All spiders were housed individually in opaque plastic containers (10-cm diam. “deli dish” food containers) and kept under a 13/11 h light/dark cycle at approximately 25° C, and constant relative humidity. Spiders were fed one to two 10-day old crickets (Acheta domesticus) twice a week. To control for effects of hunger, female spiders were also fed one cricket the day before a trial in addition to regularly scheduled feedings (if on different days). To examine how sub-adult male courtship influences adult female mate recognition and/or mate preferences, we conduct- ed two-stage experiments in which ( 1 ) females first gained experience with male courtship during their penultimate life stage (one molt prior to maturity), and (2) their receptivity to male courtship was measured as adults. Juvenile females were exposed multiple times to courting adult heterospecific or conspecific males prior to maturity. Once females were mature, we recorded their behavioral responses to an adult male of the same or different species to which they had been exposed as juveniles. As a control condition, a group of females were raised to maturity in isolation and tested at adulthood without prior exposure to males. Juvenile exposure. — Upon reaching their penultimate instar, juvenile female S. ocreata (n = 87) and S. rovneri (n = 78) were randomly assigned to one of three exposure treatment groups: 1) conspecific male exposure (S. ocreata females n — 27; S. rovneri females n = 23); 2) heterospecific male exposure ( S . ocreata females n = 35; S. rovneri females n = 26); and 3) control - no exposure (S. ocreata female n = 25; S. rovneri female n = 29). Although an effort to create equal sample sizes across treatment groups was initially made, both populations experienced parasitism and/or mortality leading to decreased and uneven sample sizes. For S. ocreata female exposure trials, juvenile females were individually placed into an arena consisting of a transparent, plastic, open-bottom box (9.5 x 9.5 X 9.8 cm LxWxH) adjacent to an adult courting conspecific/heterospecific male (depending on treatment group) (Fig. 1A) allowing females to gain experience with both substrate-borne seismic courtship cues (through the shared posterboard substrate) as well as visual cues. For S’. rovneri exposure trials, juvenile females were placed in open-bottom clear plastic (acetate) cylinders (diam- eter: 6.4 cm, height: 5.7 cm), surrounded by a larger plastic cylinder (diameter: 15.2 cm, height: 7 cm) in which the male was placed (Fig. IB). The cylindrical apparatuses were used for the later experiments because they kept the spiders better contained 172 THE JOURNAL OF ARACHNOLOGY Barrier Figure I. -Experimental apparatuses. (A) Apparatus used for S. ocreata trials. Juvenile exposure apparatus: penultimate females and adult males were placed onto a shared substrate known to conduct seismic signals (posterboard) adjacent to each other in open-bottom, transparent boxes (9.5 X 9.5 X 9.8 cm, LxWxH); adult trial apparatus: adult males and females were placed together in a rectangular arena (19.5 X 12.5 cm). The female was physically separated from the male for the first 5 minutes of the 10-minute trial in the same type of open-bottom boxed as used in the juvenile trials. (B) Apparatus used for S. rovneri trials. The same apparatus was used for juvenile exposure and adult trials, but in adult trials, the inner plastic open-bottomed circle that contained the female was removed after 5 minutes. (spiders occasionally climbed the corners of the rectangular containers) and allowed males to circle females while courting, increasing total exposure. Males and females were kept physically isolated from one another during this phase of the experiment to control for variation in male chemical cues (cuticular or silk-borne). Juvenile females were exposed to male courtship for 30 minutes every other day until they matured, as in the experiment of Hebets (2003) with S. uetzi. Males were used multiple times for exposure trials, but no female was paired twice with the same male. To ensure that multiple usages did not affect male courtship vigor, males were used for one exposure trial per day. To induce male courtship during the trial periods, silk (and pheromones thereon) of a mature conspecific female (at least 10 days post-maturity; Uetz & Norton 2007) were deposited on the male portion of the trial substrate overnight (~12 hours). Males of both species court in response to the presence of adult female silk (and the pheromones thereon), even in the absence of the female visual stimulus (Stratton & Uetz 1986 ). Adult mate recognition trials. — In the second stage of the experiment, females from all three treatment groups were assigned at random to one of two adult treatment groups: 1) conspecific male ( S . ocreata females n = 41; S. rovneri females n = 40); 2) heterospecific male (S. ocreata females n = 46; S. rovneri females n = 38). Testing began 7-14 days following each female’s final molt to standardize receptivity level (Norton & Uetz 2005; Uetz 2000). Based on their assigned treatment group, females were randomly paired with either an adult heterospecific or conspecific male. Female S. ocreata were placed in a rectangular test arena (19.5 cm X 12.5 cm; Fig. 1A) and female S. rovneri were placed in the same cylindrical apparatus used for juvenile exposure (Fig. IB). During the first five minutes of every trial the male and female were separated by a clear barrier so that female receptivity could be measured without tactile and/or chemical stimuli from the male. At the end of five minutes the clear barrier was removed and interactions between the male and female were observed for an additional five minutes to determine whether the pairing would result in copulation. Trials were videotaped for later analysis of female behavior. Females of both species perform identical stereotypic behaviors that indicate receptivity and/or willingness to copulate (Uetz & Denterlein 1979; Scheffer et al. 1996; Delaney 1997; Uetz & Norton 2007) including a slow pivot (90-360 degree slow turn or turns in place), tandem leg extend (the extension of both pairs of legs 1 and II together anteriorly while lowering cephalothorax towards substrate and raising abdomen slightly), and settle (the lowering of cephalothorax to the substrate while keeping the abdomen slightly lifted). Because females of both species behave aggressively towards males if unreceptive or if a mate is unsuitable, all cases of cannibalism and female aggression (lunging) towards the male were also recorded. A composite receptivity score (sum of receptivity displays minus lunges — as in Uetz & Roberts 2002; Uetz & Norton 2007) was also calculated for each female. Because total trial length varied depending on whether or not RUTLEDGE & UETZ— EXPERIENCE AND MATE PREFERENCE IN SCHIZOCOSA 173 Table I. Results of a two-way ANOVA on the effects of juvenile and adult treatment on female composite receptivity rates in 5. ocreata before and after removal of the transparent barrier between the male and the female. Asterisks indicate significant effects (P < 0.05). Factor df Sum of squares F-ratio P Before barrier removal Model 5 0.2144 14.2081 < 0.0001* Juvenile treatment 2 0.0010 0.1656 0.8477 Adult treatment 1 0.2116 70.1150 < 0.0001* Juv. Treat. X adult Treat. 2 0.0005 0.0893 0.9146 After barrier removal Model 5 0.1120 27.5989 < 0.0001* Juvenile treatment 2 0.0174 2.1448 0.1238 Adult treatment i 0.5123 126.2252 < 0.0001* Juv. Treat. X adult Treat. 2 0.0173 2.1371 0.1247 mating occurred, a composite receptivity rate was calculated (composite receptivity / trial length in seconds) and used for analyses (as in Rutledge et al. 2010). Statistical analyses.— -Data for the two species were analyzed separately. All composite receptivity rate data were log- transformed to improve normality. Trials in which mating did not occur and males courted for less than 10% of the total trial time (1 minute) were excluded from analysis. In all, one trial from the S. ocreata data set and two trials from the S. rovneri data set were excluded for this reason. To test whether juvenile and/or adult treatments had an effect on female mate preferences, female receptivity data were analyzed using a 2- way ANOVA with composite receptivity rate (referred to as “female receptivity” from here on) as the dependent variable and juvenile treatment group and adult treatment group as independent variables. Female receptive and aggressive behaviors that occurred prior to the removal of the clear barrier were analyzed separately from those that occurred following the removal of the barrier. Also, because Hebets (2003) found that amount of juvenile experience influenced female mate preference and/or willingness to mate with a male possessing a novel phenotype, in addition to type of experience, female receptivity and female aggression towards heterospecific versus conspecific males were tested with respect to amount of exposure. Male size and courtship vigor were factored into the statistical model; however, neither variable explained a significant portion of the variation in female receptivity and they were thus removed from the final model. RESULTS Adult treatment (heterospecific/conspecific) for both species most strongly explained variance in both female receptivity (Tables 1 & 2) and the presence/absence of copulation (S. ocreata : = 68.4, P < 0.0001; 5. rovneri: X \ = 4.39; P = 0.036). Exposed and unexposed females of both species were significantly more receptive to conspecific males than to heterospecific males (t-test: S. ocreata : t 50 = 1 1 . 156 , P < 0 . 0001 ; S. rovneri : t 50 = 6.232, P < 0.0001; Fig. 2). Receptivity towards heterospecific males did not differ between exposed and unexposed females in either species (t-test: S. rovneri: t 56 = 0.8407, P = 0.4062; 5. ocreata: t 58 = 1.7086, P = 0.0946). With two notable exceptions, mating did not occur between heterospecific individuals, nor did experience (type or amount) seem to influence mating success in conspecific pairings. Heterospecific mating occurred one time in each species. In both cases, the females were exposed to heterospecific male courtship as juveniles five or six times prior to maturation. Because female S. ocreata and S. rovneri are morphologically identical, to ensure that both matings were true hybridization events (and not the result of experimenter or collection error), the females were allowed to lay egg sacs and the resulting offspring were reared to adulthood. Upon maturation, male offspring were examined morphologically and behaviorally for hybrid indicator traits (reduced leg tufts relative to those found on S. ocreata males, and courtship behavior that is a mixture of both species; see Stratton & Uetz 1986 for a full description). In both cases, hybridization was verified. Type of juvenile experience did not affect mating outcome for either species (S. ocreata: Likelihood Ratio: x = 1 .956, P = 0.3760; S. rovneri: Likelihood Ratio: ^ = 0.850, P — 0.6539). However, in S. rovneri (but not S. ocreata ), type of juvenile experience (heterospecific, conspecific, or none) explained a significant portion of the variation in adult female receptivity rates before the barrier between the male and female was removed (Table 1), but not after. A multiple comparisons analysis revealed that during the first five minutes of trials (while the male and female remained physically separated from each other) female S. rovneri that Table 2. — Results of a two-way ANOVA on the effects of juvenile and adult treatment on female composite receptivity rates in S. rovneri , before and after removal of the transparent barrier between the male and the female. Asterisks indicate significant effects ( P < 0.05). Factor df Sum of squares F-ratio P Before barrier removal Model 5 0.0435 9.4417 < 0.0001* Juvenile treatment 2 0.0083 4.5251 0.0142* Adult treatment 1 0..0265 28.7442 < 0.0001* Juv. Treat. X adult Treat. 2 0.0054 2.9332 0.0598 After barrier removal Model 5 0.0038 7.7845 < 0.0001* Juvenile treatment 2 0.0005 0.5506 0.5791 Adult treatment 1 0.0178 36.5962 < 0.0001* Juv. Treat. X adult Treat. 2 0.0001 0.1384 0.8710 174 THE JOURNAL OF ARACHNOLOGY S. rovneri 0.05 m 246 821 -0.539 310.0 < 0.0001 373 615 -0.245 59.3 < 0.0001 (L— D)/(L+D) mean ± SE -0.303 ± 0.078 SUTER & BENSON ACTIVITY ASSESSMENT OF LYCOSOIDS 181 Table 2.—' The lycosids were strongly nocturnal in their behavior, with the exception of 1 ) a single V: a vara (shaded) that was more diurnal than would be expected by chance and 2) P. minuta, all of which were strongly diurnal. ANOVA of the (L-D)/(L+D) ratios of the nocturnal lycosids, excluding the V. avara outlier, showed no significant differences among them (F 3 2 1 = 1.967, P = 0.1499). We compared these pooled nocturnal lycosids with the pooled pisaurids (Table 1 ) and found the pisaurids to be more weakly nocturnal than these lycosids (two-tailed t 38 = 2.728, P = 0.0096). Light Dark (L— D)/( L+D) 2 r P H. lent a 210 1102 -0.680 606.6 < 0.0001 294 650 -0.377 129.5 < 0.0001 404 1 136 -0.475 345.9 < 0.0001 524 1973 -0.580 836.8 < 0.0001 490 1465 -0.499 483.5 < 0.0001 262 922 -0.557 367.4 < 0.0001 (L-D)/(L+D) mean ± SE -0.528 ± 0.042 G. pulchra 517 2987 -0.705 1735.1 < 0.0001 440 1055 -0.411 251.5 < 0.0001 291 1004 -0.551 390.8 < 0.0001 559 1980 -0.560 791.8 < 0.0001 378 770 -0.341 131.2 < 0.0001 287 877 -0.507 295.1 < 0.0001 (L-D)/(L+D) mean ± SE -0.513 ± 0.052 R. punctulata 438 2095 -0.654 1084.2 < 0.0001 665 2596 -0.592 1 1 17.3 < 0.0001 146 419 -0.483 131.2 < 0.0001 130 269 -0.348 48.3 < 0.0001 174 522 -0.500 173.5 < 0.0001 128 284 -0.379 58.8 < 0.0001 (L-D)/(L+D) mean ± SE -0.493 ± 0.048 V. avara 353 998 -0.477 306.4 < 0.0001 412 808 -0.325 127.6 < 0.0001 543 1576 -0.487 503.8 < 0.0001 958 758 0.117 23.3 < 0.001 ■ 2114 3648 -0.266 408.7 < 0.0001 2392 2934 -0.102 55.1 < 0.0001 922 1632 -0.278 197.3 < 0.0001 422 1861 -0.630 906.8 < 0.0001 (L-D)/(L+D) mean ± SE -0.367 ± 0.067 P. minuta 173 40 0.624 83.0 < 0.0001 327 140 0.400 74.8 < 0.0001 372 126 0.494 121.5 < 0.0001 1031 498 0.349 185.7 < 0.0001 503 258 0.322 87.8 < 0.0001 (L-D)/(L+D) mean ± SE 0.438 ± 0.055 activity, using 10 intervals for each average and shifting one interval for each iteration. This gave us our secondary measure of activity, short-term activity , composed of a series of indices of activity that ranged from 0-1 in steps of 0.1 (Fig. 2b), with each point being the mean of 1 50 s of binary activity. The raw data (Fig. 2a) and short-term activity (Fig. 2b) are visually quite similar, although short-term activity is more meaningful because its values reflect the degree to which activity, however energetic or lethargic, was sustained. Our tertiary measure of activity constituted an activity envelope (Figs. 2c, e), derived from the same string of 0s and Is that make up binary activity, but this time averaged over 120 intervals (1800 s) for each value, and the 120-interval blocks were contiguous (rather than overlapping as was the case with the running average that led to short-term activity). Again, the raw data (Fig. 2a) and short-term activity (Fig. 2b) and the activity envelope (Fig. 2c) are visually quite similar. For each individual spider, we averaged the two halves of the activity envelope and refer to the resulting plot as the characteristic activity profile for that spider. We used Matheinatica 8.0 (Wolfram Research) to perform all of the data manipulations described above and in Fig. 2. Further analyses of the Matheinatica outputs, including yj, t-tests, ANOVA, and multiple regressions, were performed in Prism 4.0 (GraphPad Software). RESULTS Total activity. — The total activity scores of the three species of fishing spiders (Table 1, light + dark) did not differ significantly (ANOVA: F 2 ,12 = 0.424, P — 0.664). The total activity scores of the five species of wolf spiders (Table 2) showed marginally significant variability (ANOVA: F 42 6 - 2.766, P = 0.048), the only significant difference in pairwise tests being between the most active V. avara and the least active P. minuta (Tukey's Multiple Comparison Test: q = 4.372, P < 0.05). 182 THE JOURNAL OF ARACHNOLOGY D. triton li ml i i EL ili ilLil Time (h) o /iJb. 12 4 8 16 24 Frequency (cycles/day) Figure 3- D. triton (Pisauridae) short-term activity (left) and power spectra (right). All but the last of these spiders were demonstrably nocturnal in their activity; the last spider’s activity was only marginally nocturnal, with the greater amount of its activity occurring in the dark but that had slightly less than a 5% likelihood of occurring by chance (Table 1). The power spectra show that the middle three spiders’ activity patterns were periodic at about one cycle per day whereas the first and last spiders were not obviously circadian in their activity. The first spider’s activity was approximately aperiodic as assessed with the discrete Fourier transform. D. vittatus Time (h) Frequency (cycles/day) Figure 4.- D. vittatus (Pisauridae) short-term activity (left) and power spectra (right). All of these spiders were strongly nocturnal in their activity (Table 1 ), and all had activity patterns that were periodic at about one cycle per day as shown in the power spectra. Three of the spiders also had significant periodicities at higher frequencies. SUTER & BENSON — ACTIVITY ASSESSMENT OF LYCOSOIDS 183 Figure 5. D. tenebrosus (Pisauridae) short-term activity (left) and power spectra (right). The first two and the last two of these spiders were demonstrably nocturnal in their activity, but the middle spider's activity was approximately balanced between light and dark periods (Table 1). The power spectra show that all five of these spiders’ activity patterns were periodic at about one cycle per day and all but the first and last were periodic at higher frequencies as well. H. lenta Time (h) 12 4 8 16 Frequency (cycles/day) Figure 6.-- H. lenta (Lycosidae) short-term activity (left) and power spectra (right). All of these spiders were strongly nocturnal in their activity (Table 2), and five of the six had power spectra showing highly significant periodicities at about one cycle per day. All of the spiders also had activity patterns that were periodic at higher frequencies as assessed with the discrete Fourier transform. 184 THE JOURNAL OF ARACHNOLOGY G. pulchra Time (h) Frequency (cycles/day) Figure 7. — G. pulchra (Lycosidae) short-term activity (left) and power spectra (right). All of these spiders were strongly nocturnal in their activity (Table 2), and all had significant periodicities at about one cycle per day. Five of the spiders also had activity patterns that were periodic at higher frequencies as assessed with the discrete Fourier transform. The first of these spiders appears to have been nearly continuously active during its periods of darkness, but this impression ignores the fact that only a few of the activity data reached the highest value of 1.0 which would signify that all of its ten component intervals contained activity. We pooled the activity scores of the three pisaurid species and compared those to the pooled scores of the five lycosid species. The pisaurids' mean (± SE) activity level (801.7 ± 69.7, n= 15) was less than half that of the lycosids (1750 ± 237.6, n = 31) and the difference was significant (two-tailed t 44 = 2.733, P = 0.009); the two groups’ variances also differed significantly (Pisauridae << Lycosidae: F 14 , 3 0 = 24.00, P < 0 . 0001 ). Nocturnal vs. diurnal. — All three species of fishing spiders (Table 1; Figs. 3-5) and four of the five species of wolf spiders (Table 2; Figs. 6-9) were strongly nocturnal in their activity. Of all of the species we tested, only one, the wolf spider Piratula minuta (Table 2; Fig. 10), was diurnal. The metric supporting these statements was (L-D)/(L+D), which could vary from —1 (fully nocturnal) to +1 (fully diurnal) (Tables 1, 2). The (L — D)/( L+D) ratios did not differ among the fishing spider species (Table 1), nor did they differ significantly among the four nocturnal wolf spider species (Table 2), but the pooled nocturnal lycosids were more strongly nocturnal than the pooled pisaurids (two-tailed t 38 = 2.643, P = 0.01 19). None of the individual spiders that showed statistically significant nocturnal or diurnal activity (31 of 31 lycosids, 14 of 15 pisaurids) was purely nocturnal or diurnal, an assertion supported both by the (L-D)/(L+D) ratios (Tables 1, 2) and by visual inspection of the activity records (Figs. 3-10). That is, in all individual cases except for the single ambivalent D. tenehrosus (Pisauridae), statistically strong nocturnality was accompanied by substantial activity during the light hours, and statistically strong diurnality (in all individual P. minuta and one individual V. a vara) was accompanied by substantial activity during the dark hours. Activity profiles. — We analyzed the activity profiles of the pisaurids (Fig. 11a) and lycosids (Fig. 11b) using these metrics: activity level surrounding dark onset, activity level surrounding light onset, and activity level trend through the dark period (as shown in Fig. 12). The fishing spiders and wolf spiders differed both with respect to within-family variability and with respect to overall levels of activity (above). The three pisaurids, all in the genus Dolomedes , had similarly shaped profiles (Fig. 11a) among which there were no significant differences in activity levels surrounding either the onset of darkness or the onset of light (Table 3), and there was a declining amount of activity during the dark hours that did not vary among the three species (Table 4). The same consistencies were not present among the five species of wolf spiders (Fig. 1 lb). One difference, of course, was that P. minuta was predominantly diurnal in its activity, while the other four species were nocturnal. In addition, the lycosid data revealed that activity surrounding the onset of darkness and the onset of light varied significantly among the SUTER & BENSON ACTIVITY ASSESSMENT OF LYCOSOIDS 185 Figure 8. — R. punctulata (Lycosidae) short-term activity (left) and power spectra (right). All of these spiders were strongly nocturnal in their activity (Table 2), and all had significant periodicities at about one cycle per day. The first three spiders also had activity patterns that were periodic at higher frequencies as assessed with the discrete Fourier transform. The second spider appears to have been nearly continuously active during its periods of darkness, but this impression ignores the fact that only a few of the activity data reached the highest value of 1.0 which would signify that all of its ten component intervals contained activity. species; V. avara' s conspicuous burst of activity immediately following the onset of darkness (Fig. 11b) was primarily responsible for the very low likelihood that the onset-of- darkness differences were due to chance alone (Table 3). Multiple linear regression showed that, during darkness, the activity of four of the wolf spiders (three that were nocturnal as well as the diurnal P. minuta) declined significantly while one (R. punctulata) had activity that did not change in intensity over the same period (Table 4). Although several of the lycosids displayed activity peaks early in the dark phase or early in the light phase (Fig. 11), none of them had the U- shaped profiles characteristic of crepuscular behavior in which most of the activity is expected to be concentrated at dusk and dawn (e.g., Nishimura et al. 2005). It is possible that some activity was suppressed by the abrupt light-to-dark and dark- to-light changes that we used during our trials, but the data in Figs. 3-10 do not show evidence of lasting suppression (as opposed to brief, transient suppression). Periodicity of activity. — The power spectra (Figs. 3-10), revealing how much of the variability in a spider's activity was demonstrably periodic, showed that most spiders had signif- icantly periodic activity at 1 cycle per 24 h and also at higher frequencies (frequency > 1/day, ultradian periodicities). Note that we cannot interpret significant periodicity at 1/day as evidence of an underlying physiological circadian rhythm. This is because, under a 12:12 LD light regime, that same periodicity would emerge if activity during light hours were merely suppressed (in a nocturnal spider) or stimulated (in a diurnal spider). This is why, in general, the detection and measurement of endogenous circadian rhythms is carried out in constant darkness (Aschoff 1960). The ultradian periodicities were conspicuously variable among species (Fig. 13), and were especially so among the lycosids. There, V. avara had by far the greatest number of significant periodicities at frequencies > 1/day and P. minuta , at zero, had the fewest. Overall, the fishing spiders were less likely to have higher frequency periodicities than were the wolf spiders, but most of that difference was attributable to the highly ultradian activity of one lycosid species, V. avara (Figs. 9, 13). DISCUSSION The subsets of fishing spiders (Pisauridae) and wolf spiders (Lycosidae) that we tested were interestingly different. The three congeneric species of fishing spiders were largely indistinguishable from each other, as might be expected because of their common ancestry, sharing overall activity levels, degrees of nocturnality, activity profile shapes, and having relatively few ultradian periodicities. In contrast, the five species of wolf spiders were not only different from each other but also, as a group, different from the fishing spiders. The most conspicuous family-level differences were these: 1 ) the pisaurids were about half as active as the lycosids. 186 THE JOURNAL OF ARACHNOLOGY Figure 9. — V. avara (Lycosidae) short-term activity (left) and power spectra (right). Except for 9d, all of these spiders were strongly nocturnal in their activity (Table 2), and all including 9d had significant periodicities at about one cycle per day. All except 9a also had activity patterns that were periodic at higher frequencies than one/day. The spider represented by 9d was significantly diurnal (Table 2). answering the first of our core questions; 2) the pisaurids were less strongly nocturnal than were the nocturnal lycosids (i.e., excluding the diurnal species. Piratula minuta ), partially answering the second of our core questions; and 3) there were fewer ultradian periodicities in the activity patterns of the pisaurids than there were in the activity patterns of the lycosids, completing another part of the answer to the second of our core questions. Because these family-level differences were potentially biased by our use of three congeneric species in Pisauridae, we plan a broader sampling of that family in the future. Spectrum of nocturnality. Perusal of the activity records of the 46 spiders in this study (Figs. 3-10) shows that none of the individuals was purely nocturnal or purely diurnal. Each nocturnal spider had measurable activity during multiple time intervals while under light, and each diurnal spider was active during multiple time intervals while in the dark. The variability of (L-D)/(L+D) was roughly continuous over most of its measured —0.71 to —0.10 range of nocturnality (Tables 1, 2). (The same is likely to be true of diurnality, but we have too few data from this study to make that case.) The spectrum of (L-D)/(L+D) provides the answer to the third of our core questions: our measures indicate that none of the eight species tested was strictly nocturnal or diurnal. The Five individuals with the lowest (L— D)/(L+D) ratios came closest to being purely nocturnal, with 81.5-85.2% of their activity bouts occurring during darkness. Surprisingly, these five individuals represent five different species and two families, another indicator that the data in this study revealed substantial individual variation that may be found, upon further study, to be attributable to variables we did not control (e.g., genotype, time since last feeding, mating status). The continuity of variability (Tables 1, 2) suggests that nocturnality in spiders may be a mutable characteristic, perhaps sensitive to the individual’s history and current physiological state (proximate influences), or perhaps varying at the level of population genetics, possibly both. Whatever its underlying cause, and presuming that it is not an artifact of SUTER & BENSON- ACTIVITY ASSESSMENT OF LYCOSOIDS 187 Figure 10. — P. minuta (Lycosidae) short-term activity (left) and power spectra (right). All of these spiders were strongly diurnal in their activity (Table 2), and all had significant periodicities at about one cycle per day. None had activity patterns that were periodic at higher frequencies than 1/day as assessed with the discrete Fourier transform. the austere conditions of our test chambers (see “Quality of data” below), the variability should influence the way community ecologists think about syntopic spiders and the degree to which temporal partitioning can pay a role in niche differentiation (e.g., Herberstein & Elgar 1994; Carrel 2003; Nieto-Castaneda & Jimenez-Jimenez 2009; Lapinski & Tschapka in press). Bouts. — Our DFT analyses of the activity data (Figs. 3-10) indicate that, apart from the nearly ubiquitous presence of periodicity at 1 cycle/day, all of the spiders, except for one (Piratula minuta ), also had significantly periodic activity pulses at higher frequencies (Fig. 13). As noted in the results section, the diel cycle of activity need not imply an underlying circadian rhythm, although such a physiological rhythm is likely to be present (Cloudsley-Thompson 1978, 2000; Suter 1993; Jones et al. 2011). But the higher frequency (ultradian) periodicities in most spiders' activity cannot have been driven by the 12:12 light regime and, in the very simplified environ- ment of the experimental chambers, they also cannot have been driven by external cues. These ultradian periodicities appear to be one way that the spiders organize their activity into bouts. The complexity of the etiology of bouts renders their initiation and duration difficult to understand empirically (Sugihara et al. 2012). Both stochastically initiated bouts and bouts that are the result of the interplay of several components Table 3. — Activity profiles at the times surrounding the onset of darkness and the onset of light. We compared activity profiles among the pisaurids and the lycosids (via ANOVA) and between the pooled pisaurids and lycosids (t-test). In the ANOVA analyses, Tukey’s Multiple Comparison Test revealed significant pairwise differences only between V. avara and the other lycosids in the onset-of-darkness data (vs. II. lenta , P < 0.01; vs. G. pulchra, P < 0.05; vs. R. punctulata, P < 0.001; vs. P. minuta, P < 0.01). In both t-tests between the two families, the lycosids had significantly higher activity than the pisaurids, a correlate of overall higher activity levels (also see Fig. 11). Onset of darkness (hours 5.5, 6.0, 6.5) activity ± SE (N) ANOVA or /-test parameters Onset of light (hours 17.5, 18.0, ANOVA or /-test 18.5) activity ± SE (A0 parameters D. triton D. vittatus D. tenebrosus 0.418 ± 0.118 (5) 0.350 ± 0.085 (5) 0.677 ± 0.064 (5) F 2 . 12 = 3.554, P = 0.061 0.193 ± 0.038 (5) 0.330 ± 0.057 (5) F 2A2 = 2.373, P = 0.135 0.248 ± 0.036 (5) H. lenta G. pulchra R. punctulata V. avara P. minuta 0.731 ± 0.129 ( 6 ) 0.880 ± 0.161 ( 6 ) 0.433 ± 0.144 ( 6 ) 2.210 ± 0.435 ( 8 ) 0.437 ± 0.145 (5) F 4 ,2 6 = 7.873, P = 0.0003 0.629 ± 0.152 ( 6 ) 1.510 ± 0.205 ( 6 ) 0.839 ± 0.344 ( 6 ) F 4 , 26 = 2.89 3, P = 0.042 1.335 ± 0.402 ( 8 ) 0.207 ± 0.069 (5) Pooled pisaurids Pooled lycosids 0.481 ± 0.062 (15) 1.038 ± 0.175 (31) Z 44 = 3.128, P = 0.0027 0.257 ± 0.028 (15) 0.954 ± 0.151 (31) Z 44 = 2.168, P = 0.0356 188 THE JOURNAL OF ARACHNOLOGY Table 4. — Activity profiles during darkness, excluding the onset of darkness and the onset of light (botli covered in Table 3). We used multiple linear regression to quantify changes in activity over time (see Fig. 12), using the species-level mean profiles shown in Fig. 11. Except in the case of R. punctulata, the slopes were negative, with the passage of time accounting for 40-74% of the variance in activity. This was even true of P. minuta, the only species in this group that was demonstrably diurnal (Table 2). Slope of activity (hours 7-17) activity per hour r Tl,19 P Slopes different? D. triton -0.0156 0.647 34.81 < 0.0001 D. vittatus -0.0136 0.561 24.32 < 0.0001 T 2 ,57 = 1.64, P = 0.203 D. tenebrosus -0.0205 0.732 52.01 < 0.0001 H. lent a -0.0607 0.601 28.61 < 0.0001 G. pulchra -0.0262 0.555 23.72 0.0001 R. punctulata -0.0034 0.044 0.881 0.359 F 4 , 95 = 9.64, P < 0.0001 V. avara -0.0373 0.400 12.69 0.002 P. minuta -0.0078 0.738 53.44 < 0.0001 of the internal state, may have contributed to much of the “noise” surrounding the more regular periodic bouts of activity detectable in our data. We are working to tease apart the temporal organization of these data, but apart from the DFT analysis, those analyses (especially Markov chain and fractal analyses; Asher et al. 2009) are beyond the scope of this paper. Intraspecific variation. -Several levels of intraspecific vari- ation are evident in the data shown in Figs. 3-10. In the wolf spider V. avara, for example, the individuals were conspicu- ously variable in their quantities of activity (e.g., Figs. 9d vs. 9e), in the degree of nocturnality (the spider represented by Fig. 9d was significantly diurnal, the rest were nocturnal; see also Table 2), and in the presence of ultradian periodicities (e.g.. Figs. 9a vs. 9b; see also Fig. 13). Even among the fishing spiders, in which we detected few species-level differences (Tables 1, 3, 4; Figs. 3-5, 11), individual-level differences were impressive. In D. triton , for example, the most nocturnal and the least nocturnal had (L— D)/(L+D) ratios that differed by a factor of 6.9 (Table 1), and one of the five spiders showed no significant periodicity, even at 1 cycle per day. These individual differences suggest that activity, as we have broadly measured it in this study, is neither strictly controlled by a light-dark cycle nor strongly patterned by an endogenous circadian rhythm or by immutable phylogenetic constraints. That is not to say that endogenous rhythms and phylogenetic constraints are lacking, but rather to note that other influences such as developmental history, recent experience, feeding history, and perhaps genetic variability within each species, are strong enough to override the influences not only of one nearly ubiquitous environmental variable, light, but also of the circadian rhythm and other innate patterning parameters. Finally, we have some indication from intraspecific vari- ability that transitioning from nocturnal to diurnal or vice versa may require only a gentle environmental or evolutionary nudge. First, the inter-individual variability in (L-D)/(L+D) ratios (Tables 1 & 2) shows that, far from being a two-state discrete system, nocturnality and diurnality exist on a continuum; individuals and species near zero (50:50) would require only a small shift to cross from one nominal state to the other. And second, at least in the lycosid V. avara , where nocturnality appears to be the norm, an individual (Table 2, Fig. 9d) can be demonstrably diurnal. On the evolutionary side, if more were known about the phylogeny of the genera within the Lycosidae (Dondale 2005) it might be possible to Time (h) Time (h) Figure 11. — Activity profiles of the pisaurids (a) and lycosids (b). The three species of pisaurids (b) are all in the genus Dolomedes and, perhaps because of that shared lineage, their activity profiles (gray lines) are similar and thus well represented by the average for the three species (black line). The five species oflycosids (b) represent five different genera (gray lines), four of which are nocturnal and one of them, P. minuta , is diurnal (Fig. 10, Table 2). Overall activity of the lycosids was higher than that of the pisaurids (note scale differences, and see Table 3). The data for P. minuta were excluded when we calculated the average (black line) for the lycosids. The shaded area on each graph indicates darkness in the experimental chamber. SUTER & BENSON ACTIVITY ASSESSMENT OF LYCOSOIDS 189 Figure 12. — Analysis of the activity profiles (Fig. 1 1) consisted of three parts, here shown for the activity profile of D. tenebrosus. Data surrounding the onset of darkness (open circles) were summed for each individual’s profile, then compared via ANOVA across all species in the same family. Data surrounding the onset of light (open squares) were treated in the same way. The intervening data (filled circles) for each species were subjected to multiple regression analysis, a procedure that allowed us to determine both whether the slope of each species was 0 and whether there were differences among the slopes of the species that could not be attributed to chance. The results of these analyses are reported in Tables 3 & 4. infer whether, for example, the diurnal P. minuta (Fig. 10) is a recent and unusual convert to diurnality or is one species in a clade of other species and genera that are characteristically diurnal. Quality of data. — We have two concerns about our data and analyses. First, we collected our data from individual captive spiders, each enclosed in an almost featureless chamber (see Methods). In vertebrates, the absence of environmental complexity while in captivity often leads to the expression of anomalous, sometimes repetitive behaviors (reviewed by Lewis et al. 2007), and there is no a priori reason to believe that arthropods are immune to such effects. Thus we recognize that some of the activity we detected and analyzed might not have been expressed by the spiders if they had been tested under more naturally complex conditions, and that our isolation of the spiders for testing may have led to similar artifacts. On the other hand, the activity captured by our monitoring apparatus did reveal patterns and differences that cannot have been caused by external influences and that might well have been obscured if we had collected our data under more natural conditions (dawn-like and dusk-like light transitions; prey available; refugia available). Further, in part because of the simplicity of our apparatus, we could automate data collection to a degree that would not be possible (or tractable) via most direct observational methods in more naturalistic settings, thus justifying the trade-off in external validity. Our second concern is that the data we used in our analyses were quite far removed from the actual spider behaviors that caused changes in light levels at the IR sensors. The behaviors were analog motions (e.g., leg movements during locomotion, pedipalp movements during grooming, body shifts during postural changes) that we measured digitally. In terms of behavioral specificity, those measures were far less meaningful than, for example, the measures of wheel-running activity by mice (Suter & Rawson 1968; Hut et al. 2011) that have ■ D. triton (5) □ D. vittatus (5) D. tenebrosus (5) ro U.U -r ' 1 1 1 ' 1 1 . 1 i i i i 1 ' 1 1 ' ' — 1 1 1 1 1 1 1 1 1 1 1 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 c QD h W i 1.0 - KJ ■ H. lento (6) o □ 6. pulchra (6) >- 0.8 ■M R. punctulata (6) 15 fO 0.6 - S V. avara (8) XJ o 0.4 -! ■ P. minuta (5) $ CL 0.2 - If | k 1, til I tl ti! 1| $ | ^ j 1 r 2 3 X 5 6 7 8 9 10 11 12 13 14 N — i — “ t — — i — ‘n — i — S — i — -i — i — i 15 16 17 18 19 20 Frequency (cycles/day) Figure 13.- Probability of a pisaurid (a) or a lycosid (b) evincing significant (P < 0.01) periodicity of activity at the frequencies shown. Nearly all individual spiders had the expected significant periodicity at 1 cycle/day with the exception that, in D. triton , two of the spiders did not show a significant peak at that frequency, hence the probability score of 0.6 for that species (3/5 of D. triton had a significant peak at 1 cycle/day). Overall, the lycosids were more likely to have high-frequency periodicities in their activity than were the pisaurids (x 2 = 7.19, P = 0.007, corrected for continuity; 1. 5-7.0 cycles/day vs. 7.5-20 cycles/day), and this difference was largely due to the large number of significant periodicities in the activity ot V. avara. On the other hand, only one species (P. minuta ) among all tested had no significant periodicity at frequencies greater than 1 cycle/day. The legend shows N for each species. a 1.0 - >» 0.8 - 'u 0.6 - O "l_ QJ 0.4 - Q_ +-< C 0.2 - 190 THE JOURNAL OF ARACHNOLOGY populated the vertebrate circadian rhythm literature, or the assays of araneid defensive behavior devised by Jones et al. (201 1). On the other hand, our measures integrate all forms of activity that result in motion and so, in a way, have the same general applicability that physiological measurements of metabolic rate have — the particular actions are not captured but the picture over time retains meaning (Fig. 2). Summary. — All of the fishing spiders (Pisauridae) were nocturnal in their activity, as were four of the five species of wolf spiders (Lycosidae). All of those nocturnal species and the single diurnal wolf spider species, Piratula minuta , varied substantially in the degree to which they were nocturnal or diurnal, but none could be described as crepuscular. The most nocturnal of the spiders still performed 14.8-18.5% of their activity under the bright lights of their “day.” The (L-D)/ (L+D) ratio of activity, which was the basis of our measure of nocturnal or diurnal tendencies, varied smoothly between the most nocturnal individual (-0.71) and the most diurnal individual (+0.62). The pisaurids were less active overall than were the lycosids, and they were less strongly nocturnal than were the nocturnal lycosids (excluding the diurnal P. minuta). The pisaurids also had simpler temporal patterning than the nocturnal lycosids (again excluding the diurnal P. minuta ) — our DFT analyses showed that, although all seven of the nocturnal species displayed periodic activity at frequencies > 1/day, periodicities at frequencies between 8-20 cycles per day were rare among the fishing spiders and relatively common among the wolf spiders. 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Rawson. 1968. Circadian activity rhythm of the deer mouse, Peromyscus: effect of deuterium oxide. Science 160: 1011-1014. Suter, R.B. 1993. Circadian rhythmicity and other patterns of spontaneous motor activity in bowl and doily spiders. Journal of Arachnology 21:6-22. Suter, R.B. & T.G. Forrest. 1994. Vigilance in the interpretation of spectral analyses. Animal Behaviour 48:223-225. Manuscript received 12 September 2013, revised 5 February 2014. 2014. The Journal of Arachnology 42:192 194 SHORT COMMUNICATION Submersion tolerance in a lakeshore population of Pardosa lapidicina (Araneae: Lycosidae) Carl N. Keiser and Jonathan N. Pruitt: Department of Biological Sciences, University of Pittsburgh, 213 Clapp Hall, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA. E-mail: cnk21@pitt.edu Abstract. Terrestrial animals often inhabit stochastic boundaries between terrestrial and aquatic habitats which are under constant risk of flooding. In these circumstances, terrestrial arthropods often exhibit behavioral and physiological adaptations to cope with this risk by either avoiding flooding or tolerating submersion. We present the results of a study designed to explore submersion tolerance in a lakeshore population of Pardosa lapidicina (Emerton 1885), a eurytopic lycosid. Spiders were submerged in lake water for 4, 8, 1 1, or 16 hours, then removed and tested for responsiveness. Each spider was checked for responsiveness a second time after an eight-hour period in a dry vial. Spiders that were submerged for longer periods were less likely to be responsive immediately after removal. However, between 7% and 38% additional spiders resumed activity eight hours after removal, their recovery depending on their time submerged. This suggests that adult P. lapidicina can survive long periods of submersion in a quiescent state and later resume activity. Keywords: Eurytopic lycosid. habitat Hooding, stone spider The marine intertidal, lakeshore, tidal marsh and riparian zones are inundated by recurrent though often irregular flooding, and terrestrial organisms living in these habitats must contend with abiotic stressors associated with the nearby water edge (Helmuth & Hofmann 2001; Plum 2005). Organisms that exhibit the traits necessary to successfully utilize this habitat are presented with novel and abundant resources (Leigh et al. 1987; Paetzold et al. 2008). Furthermore, many actively foraging terrestrial organisms opportu- nistically utilize these habitats only when conditions are favorable (e.g., low tide, dry seasons). The onset of flooding (e.g., tidal flux, rainfall, waves) can elicit short-term horizontal dispersal to dry habitats or vertical dispersal to dry vegetation or rocks (Morse 1997; Adis & Junk 2002). Seasonally, terrestrial arthropods often migrate as a result of ephemeral flooding such as advancing wetted fronts in dry riverbeds (Corti & Datry 2012). Nevertheless, for animals that live near the water's edge without access to aerial refugia, rapid flooding may present an unpredictable danger of drowning. Animals may reduce this risk behaviorally by finding refuge under shells, in crevices or nests, or in bubbles created by rock asperities (Rovner 1986; Maitland & Maitland 1994). In addition, physiological adaptations (e.g., submer- sion tolerance) may accompany these behavioral traits, especially in stenotopic arthropods living in salt-marshes and along lakeshores and riverbeds (Foster & Treherne 1976; Witteveen & Joosse 1988; Decleer 2003; Rothenbiicher & Schaefer 2006). For example, the salt-marsh lycosid Arctosa fulvolineata (Lucas 1846) has been shown to enter a state of hypoxic coma when submerged in salt water for extended periods of time (Petillon et al. 2009). Spiders that undergo hypoxic coma become unresponsive to external stimuli, though they are able to resume activity eight hours after removal from the water (Petillon et al. 2009). Despite a few studies on behavioral responses to flooding, submersion tolerance has not yet been tested in a lakeshore population of a eurytopic lycosid. Pardosa lapidicina (Emerton 1885) is a wolf spider which inhabits rocky habitats, from talus slopes to rocky shorelines (Eason 1969; Bradley 2012). Some populations of P. lapidicina have been shown to migrate back and forth along the marine intertidal, following the tides (Morse 1997), allowing them to take advantage of novel foraging opportunities (Morse 2002). Many Pardosa species have been shown to exhibit rapid locomotion along water surfaces via a characteristic rowing behavior (Stratton et al. 2004). However, if a spider is caught under a rock or in an exposed crevice during high tide, under a wave, or during a Hash flood, locomotor responses may be insufficient to save it from drowning. The ability to withstand drowning may be especially important for populations near bodies of water with unpredictable changes in surface level. This could occur along the shores of the Great Lakes in areas that experience heavy boating activity and seiches (i.e., standing waves occurring in enclosed bodies of water produced by atmospheric disturbances and storms) (Gedney & Lick 1972; Herdendorf 1987). Gibraltar Island on Lake Erie is home to a population of P. lapidicina whose range, al least for part of the year, is limited to a few small rocky shorelines that experience drastic and sudden changes in wave size and water level ( pers. observation). How might individuals cope with sudden inundation and what would be the survival consequences. In this paper, we address two questions: ( 1 ) Will individual P. lapidicina be responsive after submersion for extended periods? and (2) Will initially unresponsive individuals later resume activity? Adult P. lapidicina (n = 43) were collected from two small rocky lakeshores along the eastern side of Gibraltar Island in the Bass Island region of Lake Erie. Experimentation took place during June 2013 when both adult males and females were present, one day after a mayfly emergence and the day before a storm with wind gusts up to 17 m/s (NOAA National Data Buoy Center). Under these conditions, spiders had likely fed ad libitum in the field, and were collected one day prior to a weather event that could have produced our experimental conditions in situ. After 24 hours in captivity, the mass of each spider was measured on a digital scale. Spiders were then submerged individually in vials filled with freshly collected lake water and the vials were submerged in a large container to standardize ambient water temperature (18.7°C 18.8°C over the course of the experiment). Care was taken to ensure that all air bubbles were expelled from the vials. Spiders of both sexes were randomly assigned to groups that would be submerged for 4. 8, II, or 16 hours. The resulting groups were composed as follows: 4 hours: 6 female, 3 males; 8 hours: 6 females, 2 males; 11 hours: 12 females, 2 males; 16 hours: 6 females, 5 males). At the end of submersion, each spider was individually placed under a dissecting microscope, ventral side up. After a 30 second acclimation period, the ventral abdomen was stroked with a fine paintbrush every 5 seconds for three minutes. The proportion of individuals that resumed activity after submersion was recorded for each submersion duration. Individuals were then placed in dry vials and allowed 8 hours to recover from the submersion, at 192 REISER & PRUITT SUBMERSION TOLERANCE 193 Figure I . The proportion of spiders responsive to tactile stimuli after removal from the water decreased the longer they were submerged (x 2 3 = 19.8, p = 0.0002). which point they were re-tested for responses to tactile stimulation. Voucher specimens were placed in the Spider Biology teaching collection at Stone Laboratory and the Pruitt Lab at the University of Pittsburgh. Data were analyzed with two nominal logistic regressions with time submerged, sex, and body mass (g) as independent variables and one of two nominal dependent variables: (i) responsiveness of individuals immediately after removal from the water and (ii) resumption of activity 8 hours after removal. Spiders that spent more time submerged were less likely to be responsive to tactile stimulus immediately after removal from the water (x 2 3 = 19.8, p = 0.0002; Fig. 1). This trend did not differ between sexes (x “ i = 0.74, p = 0.39) and was not influenced by body mass (x 2 i = 0.04, p = 0.84). However, some spiders were active 8 hours after the end of submersion even though they had been unresponsive immediately after submersion, and that recovery was influenced by time submerged ( x 2 1 = 22.9, p < 0.0001; Fig. 2). All spiders that were responsive immediately and 8 hours later remained alive and ambulatory in captivity for 48 hours after experimentation. This suggests that, in the case that an adult spider is inundated by rising water level, it may survive up to 11 hours of submersion in a quiescent state, and later resume activity. It is unknown if this observation is the result of physiological adaptations like hypoxic coma (Petillon et al. 2009) or anatomical artifacts such as patterns of setae which capture extra air bubble volume as in the diving bell spider and other diverse spider families (Suter et al. 2004; Seymour & Hetz 2011). It is surprising that body mass did not play a role in survivorship, as body size can be pivotal in the success of attached bubbles as physical gills for terrestrial arthropods (Anderson & Prestwich 1982; Seymour & Matthews 2013). It may be that the spiders used in this study did not vary enough in body mass within each sex (females: 0.07 ± 0.03g; males: 0.03 ± 0.006g) to allow detection of an effect of body mass on survivorship. Furthermore, tradeoffs between larger body size and surface:volume ratio could mask many differences between large and small individuals (e.g., Tufova & Tuf 2005). In order to fully understand resistance to drowning in lycosids, comprehensive studies should simultaneously test the relationship between Hood avoiding behavior (e.g., Stratton et al. 2004; Lambeets et al. 2008), physiological submersion tolerance (Petillon et al. 2009) and hydrophobic anatomical characters (Stratton et al. 2004; Seymour & Hetz 2011). Comprehensive studies exist on behaviors like water surface locomotion in terrestrial spiders (Stratton et al. 2004) from Time submerged (h) Figure 2. — More spiders were responsive 8 hours after removal than were immediately after removal, and submergence time drove this trend (x'i = 22.9, p < 0.0001). No spiders which had been submerged for 16 hours were responsive immediately after removal or 8 hours later. Photo by Tom Adams. which information can be derived to further understand the strategies employed by different species before and after submersion. Further- more, studies across life stages may address life history tradeoffs and stage-dependent strategies. For example, during the collection period, many female spiders were observed carrying egg cases. It is unknown how submersion affects P. lapidicina eggs, though submersion tolerance has been observed in the egg stage of two Allomengea spp. Strand (Araneae: Linyphiidae) (Rothenbucher & Schaefer 2006). The propensity to evade flooding conditions may be experiential, an artifact of habitat specialization and/or plenotypic plasticity, or a product of adaptation (Morse 2002; Lambeets et al. 2008, 2010). Subsequent studies which test spiders across habitats may also broaden our understanding of local adaptation within populations across variable habitats very near one another. Lycosids along small inland ponds have been shown to migrate very little over time, suggesting that habitat retention may be adaptive in habitats with reliably stable water edges (Ahrens & Kraus 2006). Lastly, detailed studies across sites with varying anthropogenic activity will illuminate the influence of human-induced rapid environmental change (Sih et al. 2011; e.g., the production of boat wakes and the introduction of invasive salt-marsh grasses; Petillon et al. 2010) on the emergence, persistence, or loss of behavioral and physiological defenses against habitat flooding. 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E-mail: draneym@uwgb.edu Abstract. We conducted systematic sampling to examine the microhabitat distribution of the Nearctic linyphiid Drapetisca alteranda Chamberlin 1909; adults are found almost exclusively on tree trunk surfaces. Sampling was conducted in a 1 ha plot in which all trees over 10 cm dbh had previously been identified, mapped, and measured. Tree trunks were sampled for D. alteranda by brushing spiders into beating sheets. We sampled equal trunk surface areas (0. 5-2.0 m) of the four most abundant tree species on the plot: Quercus alba, Fraxinus pennsylvanica, Tilia americana, and Carya ovata. We measured tree bark furrowing depth at 15 locations around each tree. We analyzed the data with a General Linear Mixed Model, assuming Poisson distribution. Tree species and furrowing depth, but not tree size, were significant predictors of total number of D. alteranda collected. Eighty-four percent of the spiders were collected on T. americana, and the relationship between spider abundance and furrowing depth was negative. As a separate test for D. alteranda vertical distribution, we divided the lower 3 m of selected tree trunks into six 0.5 m sections, sampling each separately. Regardless of tree species, height above ground was a significant predictor of female (but not male) D. alteranda occurrence, with 52% of the females found 0.5-1 .0 m above the forest floor. These results suggest that the microhabitat distribution of D. alteranda is broadly similar to that of the Eurasian species D. socialis, a species that matures in leaf litter and migrates mostly to the lower regions of tree boles to forage as adults. Keywords: Linyphiid spider, habitat selection, vertical distribution, Drapetisca socialis Microhabitats (i.e., small scale, localized environments) are characterized by unique ecological features including temperature, humidity, substrate types, species assemblages, and predator-prey relationships (Ziesche & Roth 2008). Microhabitat selection is important to the survival and successful reproduction of many species of arthropods and has been shown to play a pivotal role in regulating population dynamics and maintaining biodiversity (Michel & Winter 2009). Trees provide important sources of microhabitats in forest ecosystems due in part to their large biomass and structural complexity. Specific microhabitat types include foliage, branches, and trunks, as well as smaller scale features such as cavities, cracks, scars, broken tops, bowls, and burls (Szinetar & Horvath 2005; Michel & Winter 2009). Numerous spider species have evolved a specialized life history that depends on the microhabitats that tree trunks provide (Aikens & Buddie 2012). However, relatively few studies have been published on tree-trunk-dwelling spiders, and much remains unknown about their ecology and life history (Szinetar & Horvath 2005). Several of the five species (Platnick 2013) of the sheetweb-weaving spider (Linyphiidae) genus Drapetisca represent examples of tree-trunk microhabitat specialists. Most of what we know about the ecology of Drapetisca is from studies of the Palearctic species Drapetisca socialis (Sundevall 1833). This species is occasionally found under leaves on the ground, but adults are usually collected from the surface of various species of deciduous and coniferous trees (Toft 1976; Schiitt 1995, 1997; Simon 2002; Szinetar & Horvath 2005). The study species is Drapetisca alteranda Chamberlin 1909, which occurs in forested areas of Alaska and Canada, eastern United States as far south as the Appalachians in Tennessee and North Carolina, and in higher elevation forests in the Rocky Mountains as far south as New Mexico (Buckle et al. 2001; M.L. Draney, unpublished data). Drapetisca alteranda is so morphologically similar to the Palearctic species Drapetisca socialis that D. alteranda was confused with D. socialis before it was distinguished by Chamberlin (1909). This morphological similarity suggests a null hypothesis of ecological similarity, and the available evidence supports this idea. Like D. socialis, D. alteranda is occasionally found under leaves on the ground, but is usually collected from the surface of various species of deciduous and coniferous trees, including aspens, birches, and beeches (Gertsch 1949), cedar and pines (Stratton et al. 1979), and spruce and elm (Kaston 1948). The objective of this paper is to document the microhabitat preferences of D. alteranda in a northern temperate deciduous forest. Specifically, we wanted to learn whether the presence of D. alteranda was related to tree species, tree size, or depth of bark furrowing, and whether the distribution of the spider within a tree was random with respect to distance from the forest floor. We also determined whether the microhabitat distribution within and among trees was related to the sex of the individual. This study was conducted in the Mahon Woods Forest Dynamics Plot located on the University of Wisconsin-Green Bay campus in Brown County, Wisconsin, USA (44° 3 1 '4 1 . 1 9"N, 87° 55'39.90"W). The Cofrin Arboretum Forest Dynamics Plot was established in 2005 and is one hectare subdivided into 27 20 m X 20 m subsections. Trees greater than 10 cm in diameter at breast height (DBH) have been measured, given a unique identification number, and classified to species (A. Wolf; unpublished data). Thus, the location of each tree can be mapped (Fig. 1), specific individuals within the plot can be located easily for sampling, and quantitative data are readily available for tying species occurrence to specific microhabitat features. Examples of tree species commonly found within the plot are Carya ovata , Fraxinus pennsylvanica , Acer negundo, and Primus serotina. Ground layer plants include Circaea lutetiana. Geranium maculatum, Geum canadense, and Arisaema triphyUum. Sampling was conducted from September through October 2012 between 1000 and 1700 h. times when catch rates of D. alteranda were thought to be the highest (M.L. Draney; unpublished observ.). Sampling for spiders was conducted by brushing the entire 195 196 THE JOURNAL OF ARACHNOLOGY Figure 1. -The spatial distribution of D. a/teranda ( n = 33) collected on 93 of the four most abundant tree species. Symbols indicate the presence (closed symbols) or absence (open symbols) of D. alteranda by tree type: Tilia americana (cross), Quercus alba (square), Fraxinus pennsylvanica (circle), and Cary a ovata (triangle). The size of each closed symbol is proportional to the number of D. alteranda caught on each tree, ranging from one to live. The contour lines represent two-meter intervals. circumference of tree trunks using horsehair drafting brushes. Spiders were brushed onto white nylon ripstop beating sheets ( 1 m X 1 m; Bioquip, Inc., Rancho Dominguez, CA), placed in labeled plastic jars and later preserved in 70% ethanol. All spider identifications were confirmed by the first author, and vouchers were deposited at the Field Museum of Natural History, Chicago, Illinois, USA. Brushing continued until no more organisms were observed; our observations suggest this method reduces the possibility of catching more spiders on surfaces where the method works more efficiently, because more time was spent brushing larger trees and trunks with more deeply furrowed bark. Four to five collectors participated in each of the two sampling protocols below. In order to reduce between-collector variability, the first author trained all collectors to use the same technique, and collectors always worked in pairs, rather than sampling trees individually. Selected trees were never resampled during the study. Twenty-one of the 27 subplots within the Mahon Woods Forest Dynamics Plot were randomly assigned to this study objective, and the four most abundant species were selected including Quercus alba , Fraxinus pennsylvanica , Tilia americana , and Carya ovata. Individual trees were ranked by DBH within each species. We calculated the surface area of the part to be sampled of each tree, which was 0.5 to 2.0 m above ground level, assuming trunks are cylinders without bark furrowing, etc., using the formula 1.5 m X circumference. We selected trees starting with the species that had the fourth largest surface area, and sequentially selected trees of the other three focal species, from largest to smallest, until a similar cumulative trunk surface area was obtained (i.e., surface areas were standardized). Furrowing of tree bark (grooves in bark) was determined by measuring the depth of furrows at 15 random locations around each tree. Measurements were averaged for a proxy of furrowing depth (Michel et al. 2011). Drapetisca alteranda was collected from a 1.5 m section on the tree, 0. 5-2.0 m above the ground. Six 20 m X 20 nr subplots within the Mahon Woods Forest Dynamics Plot were randomly selected to test whether D. alteranda microhabitat selection was random with respect to tree trunk height. Plots and trees (>I0 cm DBH) within plots were randomly selected each day of sampling. Focal trees were divided into six 0.5 m sections with flagging, starting where the tree trunk intersected with the forest floor. Sections (from forest to canopy) included: 0-0.5 m, 0.5- 1.0 m, 1.0-1 .5 m. 1 .5-2.0 m, 2.0-2. 5 m, and 2. 5-3.0 m. For the assessment of vertical distribution, the sex of captured individuals was determined in the field using the structure of the genitalia. The effect of explanatory variables including tree species, tree trunk height relative to the forest floor, tree diameter, and furrowing depth on the total number of D. alteranda collected were analyzed using a generalized linear mixed model (GLMM) implemented using the GLIM MIX procedure in SAS (Enterprise Guide 5.1). The GLIM- MIX procedure was selected because unlike other approaches (e.g.. MIXED), GL1MMIX generalizes data analysis in that response variables can have a non-normal distribution (see below). Pair-wise correlations and standard residual analyses (Shapiro-Wilk test, a = 0.05) were conducted between all explanatory variables to detect colinearity, deviations from normality and non-normal residual structure. No evidence of multicolinearity between independent variables was found. The number of D. alteranda collected was considered Poisson distributed due to the low capture rate of spiders, which were skewed heavily towards zero. All possible combinations of model variables (including two-way interactions) were fit, and each statistical model was evaluated using the Akaike Information Criteria (AIC) to select the most parsimo- nious set of variables explaining variation observed in the total number of spiders collected. Statistical significance of variables was declared at P < 0.05 for all tests. Models were also evaluated separately for each sex when the information was available. Post hoc tests were used to determine significant differences between categor- ical variables such as tree height. Sixty-two trees were sampled to test for the effect of tree species, tree diameter and furrowing depth on spider abundance (« = 15, Q. alba\ n = 16, F. pennsylvanica ; n = 16, T. americana ; and n = 15, C. ovata). Total surface area of tree trunk sampled was 317 nr. Average diameter at breast height (± SD) for all trees combined was 1 10.6 ± 33.5 cm (113.3 ± 30.8 cm in Q. alba , 107.3 ± 45.6 cin in F. pennsylvanica. 1 10.3 ±21.3 cm in T. americana , and 1 1 1.3 ± 36.5 cm in C. ovata). Average DBH was not significantly different among species (ANOVA, F 3>57 = 0.08, P = 0.91). Average furrowing depth (± SD) was 5.7 ± 3.7 mm (7.3 ± 4.6 mm in Q. alba , 6.1 ± 4.2 mm in F. pennsylvanica , 3.5 ± 1.4 mm in T. americana. and 5.9 ± 3.1 mm in C. ovata). Furrowing depth was significantly different among tree species, and T. americana had the least furrowed bark on average (ANOVA, F 3j57 = 3.32, P = 0.02). Nineteen D. alteranda were collected for this study objective and generally found in the greatest abundance on the western edge of the Forest Dynamics Plot (Fig. i). Drapetisca alteranda was observed on ~ 20% of the trees sampled. The best fitting GLMM model to the data based on AIC included furrowing depth, tree diameter, and tree species. However, only tree species (GLMM, x~ = 19.30, P = 0.0002) and furrowing depth (GLMM, x~ = 10.98, P = 0.0009) were significant predictors of the total number of Drapetisca collected. The greatest proportion of spiders collected ( — 84%) was found on T. americana , and —5% (n = 1) on each of the other three tree species (Fig. 2). The relationship between spider abundance and furrowing depth was negative (/) = -0.54). We also found evidence of a weak, but significant, species X furrowing depth interaction (GLMM. x" = 10.62, P = 0.01), indicating that within a species D. alteranda is positively associated with individual trees that are significantly less furrowed. DRANEY ET AL. MICROHABITAT DISTRIBUTION OF D. ALTERANDA 197 Figure 2— The average number (+ SE, per tree) of D. alteranda collected on the four most abundant tree species within the Mahon Woods Forest Dynamics Plot, Green Bay, Wisconsin. Thirty-five trees (surface area = 732 nr) across nine different species (the four focal species from the above study, plus Acer saccharum , Populus tremuloides , Primus serotina, Quercus rubra , and Quercus macrocarpa ) were randomly selected and sampled to test for the effect of tree trunk height on spider abundance. Twenty D. alteranda (14 female and 6 male) were collected on 18 trees from six of the nine tree species (52% of those sampled) from mid-September through mid-October, 2012. The best-fitting GLMM model to the data based on AIC included both tree trunk height and tree species. Tree species was a significant predictor of spider occurrence (GLMM, yj = 16.41, P = 0.03), and T. americana was again the preferred species (55% of the total). Although ~ 45% of D. alteranda collected were found at the 0. 5-1.0 nr height category, the distribution of D. alteranda with respect to distance from the forest floor was non- significant (GLMM, x 2 = 6.61, P = 0.25) or random when sexes were analyzed together. However, when analyzed separately by sex using the same model parameters, tree trunk height was a significant predictor of female D. alteranda occurrence (GLMM, x 2 = 1 1 -84, P = 0.03; Fig. 3), with 52% of the individuals found 0. 5-1.0 m above the forest floor. There was no evidence of such a relationship for males. The interaction between tree species and tree trunk height was also non-significant (P > 0.05), indicating that the behavior of spiders is consistent regardless of tree species. This study is the first to document the microhabitat preferences of Drapetisca alteranda. Our results show that IX alteranda is not randomly distributed either among or within tree trunks. On the plot level, collections of D. alteranda were concentrated toward the western side of the plot. However, examination of the sampled tree species shows that most D. alteranda were sampled from T. americana, and that the selected trees were very much aggregated toward the western side of the plot. Thus, at the plot level, D. alteranda distribution seems to be controlled by the distribution of tree species, and Fig. 1 reflects tree species distribution rather than spatial distribution of D. alteranda per se. Drapetisca alteranda were found significantly more often on Tilia americana than on the other three most abundant tree species examined, and Tilia americana had significantly shallower bark furrowing (i.e., smoother macro-scale bark texture). Furthermore, it was observed that D. alteranda microhabitats were positively correlated with individual trees that are significantly less furrowed within a species. Thus, the data suggest that the spider selects trees with less bark furrowing to locate the web site. There are a number of possible reasons for this. It seems likely that a smoother trunk surface Height above ground surface (m) Figure 3. — The average number (+ SE) of D. alteranda collected across six subsections of tree trunk within the Mahon Woods Forest Dynamics Plot, Green Bay, Wisconsin. 0-0.5 m, 0.5-1 .0 m, 1 .0—1 .5 m, 1. 5-2.0 m, 2.0-2. 5 m, and 2. 5-3.0 m beginning at the interface of the trunk and the forest floor. facilitates construction or function of the reduced signaling web or that smooth bark facilitates foraging using the setal trap (Schiitt 1995, 1997). Height above ground surface is predictive of the catch of female, but not male, D. alteranda. The majority of females were collected at 0. 5-1.0 m above the forest floor. The different vertical distribution patterns of males and females is not altogether surprising, given that males probably wander somewhat randomly over the surface of tree trunks in search of receptive females, whereas females seem to exhibit a high level of microsite fidelity. As demonstrated in other species (Romero & Vasconcellos-Neto 2005), microsite selection is potential- ly strongly related to reproductive success among females, because the web site influences both survival and foraging success. Our results on the microhabitat distribution of D. alteranda are in broad agreement with what is known about the Palearctic species Drapetisca socialis and suggest that the two species are not only morphologically but also ecologically similar. Although tree species choice has not been rigorously tested in D. socialis, Schiitt (1995, 1997) found that the species was strongly associated with Fagus sylvatica, a species that, even more than Tilia americana, has relatively smooth bark. Two studies of vertical distribution of D. socialis are broadly consistent with what we found for D. alteranda. Schiitt (1997) found the majority of specimens at 0.5-1.75 m above ground level. Also in agreement with our study, Schiitt (1997) found no individuals below 0.25 m. Simon (2002) found more than 80% of the individuals of D. socialis at the lowest level (1.5 m), less than 15% at 5 m, less than 3% at 10 m, and no individuals were located at 13 m or in the crown of the tree. Simon (2002) shows very clearly that D. socialis is a specialist on the lower bole of the tree and not the canopy, and our data are consistent with the hypothesis that D. alteranda is similar in that regard. Interestingly, the few known specimens of the Chinese species Drapetisca bicruris (Tu & Li 2006) were not found specifically on tree trunks, but were collected “from the roots of a tree, and especially the hollow in an old tree” (Shuqiang Li pers. comm.). The present study provides evidence that Drapetisca is a lineage of ecological specialists whose adults inhabit the surface of the lower portion of tree trunks. Our study suggests that even such tree-dwelling “microhabitat specialists” as Drapetisca are highly affected by their adjacent soil and ground layer environment, and that persistence of these specialists requires maintenance of these ecosystem components. These basic findings not only begin to elucidate the ecology of D. 198 THE JOURNAL OF ARACHNOLOGY alteranda, but further allow us to ask more sophisticated questions about their functional role in the forest ecosystem. Additionally, these findings should increase the efficiency by which these somewhat cryptic animals can be sampled, by focusing sampling efforts on smooth-barked trees at 0.5- 1.0 m above ground level. This should enable researchers to better study the animals, and enables the taxon to be included in forest management planning and monitoring activities. ACKNOWLEDGMENTS Thanks to students in Dr. Forsythe and Dr. Draney’s Fall 2012 Ecological and Environmental Methods and Analysis course, including 1. Aulik, S. Denomme, B. Fritsch, S. Greatens, N. Huibregtse, W. Lobner, B. Mader, C. Meyer, W. Piumbroeck, A. Puckhaber, R. Schiller, M. Wentland, K. Wilke, and R. Zelin for help with experimental design, data collection, and preliminary analysis. Thanks to Gary Fewless, curator of UW-Green Bay’s Cofrin Herbarium, for an orientation to the Mahon Woods Forest Dynamics Plot and for information about the vegetation of the site, and to Drs. Amy Wolf and Robert Howe for establishing the Forest Dynamics Plot and for sharing tree census data. LITERATURE CITED Aikens, K.R. & C.M. Buddie. 2012. Small-scale heterogeneity in temperate forest canopy arthropods: stratification of spider and beetle assemblages. Canadian Entomologist 144:526-537. Buckle, D.J., D. Carroll, R.L. Crawford & V.D. Roth. 2001. Linyphiidae and Pimoidae of America north of Mexico: Checklist, synonymy, and literature. Part 2. Pp. 89-191. In Contributions a la Connaissance des Araignees (Araneae) d’Amerique du Nord. (P. Paquin & D.J. Buckle, eds.). Fabreries, Supplement 10. Chamberlin, R.V. 1909. The American Drapetisca. Canadian Entomologist 41:368. Gertsch, W.J. 1949. American Spiders. D. Van Nostrand, Princeton, New Jersey. USA. Kaston, B.J. 1948. Spiders of Connecticut. State Geological and Natural History Survey Bulletin 70. Michel, A.K. & S. Winter. 2009. Tree microhabitat structures as indicators of biodiversity in Douglas-fir forests of different stand ages and management histories in the Pacific Northwest, U.S.A. Forest Ecology and Management 257:1453-1464. Michel, A.K., S. Winter & A. Linde. 2011. The effect of tree dimension on the diversity of bark microhabitat structures and bark use in Douglas-fir (Pseudotsuga menziesii var. menziesii). Canadian Journal of Forestry Research 41:300-308. Platnick, N.I. 2013. The World Spider Catalog, version 13.5. American Museum of Natural History, New York. Online at http://research.amnh.org/iz/spiders/catalog/INTROi .html Romero, G.Q. & J. Vasconcellos-Neto. 2005. Spatial distribution and microhabitat preference of Psecas chapoda (Peckham & Beckham) (Araneae, Salticidae). Journal of Arachnology 33:124-134. Schiitt, K. 1995. Drapetisca socialis (Araneae: Linyphiidae): Web reduction — ethological and morphological considerations. Euro- pean Journal of Entomology 92:553-563. Schiitt, K. 1997. Web-site selection in Drapetisca socialis (Araneae: Linyphiidae). Bulletin of the British Arachnological Society 10:333-336. Simon, U. 2002. Stratum change of Drapetisca socialis re-examined (Araneae, Linyphiidae). Arachnologische Mitteilungen 23:22-32. Stratton, G.E., G.W. Uetz & D.G. Dillery. 1979. A comparison of the spiders of three coniferous tree species. Journal of Arachnology 6:219-226. Szinetar, C. & R. Horvath. 2005. A review of spiders on tree trunks in Europe (Araneae). European Arachnology 1:221-257. Toft, S. 1976. Life-histories of spiders in a Danish beech wood. Natura Jutlandica 1 9:5^40. Tu, L. & S. Li. 2006. A new Drapetisca species from China and comparison with European D. socialis (Sundevall, 1829) (Araneae: Linyphiidae). Revue Suisse de Zoologie 113:769-776. Ziesche, T.M. & M. Roth. 2008. Influence of environmental parameters on small-scale distribution of soil-dwelling spiders in forests: What makes the difference, tree species or microhabitat? Forest Ecology and Management 255:738-752. Manuscript received 9 August 2013, revised 18 February 2014. 2014. The Journal of Arachnology 42:199-201 SHORT COMMUNICATION Diet composition and prey selectivity by the spider Oecobius concinnus (Araneae: Oecobiidae) from Colombia Luis Fernando Garcia 1 - 2 , Mariangeles Lacava 1 and Carmen Viera 1 - 2 - 3 : ‘Laboratorio de Ecologia del Comportamiento, Institute de Investigaciones Biologicas Clemente Estable, Avenida Italia 3318, Montevideo, Uruguay; 2 Secci6n Entomologia, Facultad de Ciencias, Igua 4225, Universidad de la Republica, Montevideo, Uruguay Abstract. The feeding ecology of most Oecobius species is poorly understood; nevertheless, the limited literature available suggests that obligate myrmecophagy is common in this genus. Recent evidence suggests that some species might do not share this trait, but could be locally specialized predators. We describe the diet and prey selectivity of the spider Oecobius concinnus (Simon 1893), a common pantropical species. Samplings of actual and potential prey for this species were made in the city of Ibague, Colombia. Ants were the dominant prey. Other prey included in its diet were dipterans. These results suggest that O. concinnus is not an obligate myrmecophagous spider. Nevertheless, further studies will evaluate other aspects of the biology of this species to reveal its trophic strategy. Keywords: Stenophagy, prey selection, natural diet, synanthropic Ants, being very abundant organisms in almost all terrestrial environments, are a potential food source for a wide range of predators (Holldobler & Wilson 1990), but also have an arsenal of defenses that deter many potential natural enemies. Predators that routinely feed on ants (myrmecophages) are of particular interest in the context of understanding how the defenses of ants can be circumvented. Among spiders, 14 of 112 of the known families contain species that include ants on their diet (Cushing 2012). Yet, important questions remain concerning the level to which myrmeco- phagous spiders have become adapted to feeding specifically on ants. When a spider is found to be myrmecophagous, it also becomes of interest to determine whether it feeds occasionally on ants (oppor- tunistic ant feeders) or includes them as the only prey in its diet (obligate ant feeders). The approaches for the study of myrmeco- phagy in spiders include observations of the natural diet and laboratory trials where adaptations for the consumption of ants can be tested (Huseynov et al. 2008). Nevertheless, studies about the diet composition of myrmecophagous spiders are scarce (Jackson & Nelson 2012). Spiders of the genus Oecobius have been traditionally known for their extreme ant-eating habits, since some observations suggest that these spiders reject other arthropods as prey. Some authors even propose that this family presents modified structures like the gnathocoxae and reduced chelicerae as adaptations for ant consump- tion (Glatz 1967). Nevertheless, a recent study on the diet and feeding behavior of different populations of the spider Oecobius navus (Blackwall 1859), performed by Liznarova et al. (2013), showed that this species consumes other prey beside ants, and the frequency of consumption of certain prey items varies locally, contradicting the previous hypothesis about ants as the only prey. In spite of this, the information about natural diet and feeding behavior of Oecobius spiders is limited, so it is unknown how prevalent extreme myrmecophagy is in this genus. In order to test whether other spiders of the genus Oecobius feed predominantly on ants or, as in the case of O. navus, catch a variety of arthropods, we analyzed the natural diet and studied the prey selectivity of Oecobius concinnus (Simon 1893), a pantropical species mainly associated with urban zones. If O. concinnus feeds only on ants, as suggested for other Oecobius species, we expected a diet composed exclusively of ants. A Corresponding author. E-mail: anelosimus@gmail.com marked selectivity of certain ant groups or subfamilies by O. concinnus could indicate whether it is a strict ant specialist, since a common trait of obligate ant specialists suggests that they prey more frequently on a certain ant subfamily, as has been shown for certain zodariid spiders, which feed mainly on formicine ants (Pekar 2004). We evaluated the diet composition (i.e., actual prey) in populations of O. concinnus present in the urban area of Ibague, Colombia, between November 2010 and January 2011. Spiders and their potential prey were sampled during 12 h, which were randomly distributed (one hour per day) on building walls at six different sites in the city; together, all the sampling points comprised an area of 6 m. Captured prey were removed from webs of adult females and subadult individuals (identified by size or presence of eggsacs inside the web), a procedure performed only once per web. Since carcasses of captured prey may remain attached next to oecobiid webs for some time (Voss et al. 2007), they most likely reflect prey consumed by the spider. Because some prey might become ensnared on the web without being consumed, and taking into account that Oecobius spiders always wrap their prey before feeding on them (Glatz 1967; Liznarova et al. 2013), only wrapped prey were considered in the diet analysis. Well-preserved specimens were deposited in the entomolog- ical collection of Southcolombian University (Universidad Surco- lombiana). The sampling protocol for potential prey followed the procedure used for actual prey. All arthropods found on the walls next to O. concinnus webs were sampled by two collectors during one hour. We searched crevices and other possible hiding places and placed the collected individuals in vials of ethanol (70%). Sampling hours of potential prey were randomly distributed at different daytime hours (one sampling hour per day); namely in the morning between 10:00- 12:00 a.m., at noon, between 4:00-6:00 p.m. and in the night between 7:00-9:00 p.m. We used this procedure to collect potential prey with different circadian activities. We selected this sampling method since other techniques such as sticky traps, which ants can easily avoid, may not sample ants and other crawling arthropods adequately (Voss et al. 2007). Since Oecobius spiders build a sensing web (Cardoso et al. 2011) and mostly capture walking arthropods (Liznarova et al. 2013), our sampling method was focused towards crawling insects. In spite of this, we collected some Hying insects that were found walking on the walls. Prey captured by web were classified to the lowest taxonomic level allowed by their condition and grouped into morphospecies when the 199 200 THE JOURNAL OF ARACHNOLOGY Table 1. — Percent of captured and available prey found in the same microhabitats as Oecobius concinnus. The category “others” includes arthropods of the groups Araneae, Blattodea, Collembola and Coleoptera. Prey order Captured (%) Available (%) Hymenoptera 99 94 Diptera 1 3 Others 0 3 N 223 527 species could not be identified. We measured selectivity for each species using the Savage selectivity index (Wi). This index measures selectivity as the ratio of each consumed prey, divided by the proportion of this prey among available prey. Statistical significance for this index was found using a chi-square test with a sequential Bonferroni Correction (Manly et al. 2002). Significant values for the chi-square test indicate a biased selectivity toward a certain prey species, while non-significant values indicate no selectivity. In order to evaluate similarity between species composition on actual and potential prey, we used the Morisita index (Krebs 1999). Statistical analyses for the Savage selectivity index were made within the software R for Windows 2.13.1 (R Development Core Team 2012). The Morisita similarity index was computed using the software Past 2.17c (Hammer et al. 2001). We sampled 223 individuals and found the same number of captured prey (only one prey per web was found and collected). All collected prey belonged to the orders Hymenoptera and Diptera. For hymenopterans, the only recorded family was Formieidae, while for dipterans it was Chironomidae. We observed a marked prevalence of hymenopterans, which composed about 99% of the diet as opposed to dipterans, with only \%. Potential prey were represented by 572 individuals grouped into six orders. The order Hymenoptera (Formieidae) was the most frequent, representing 94%, followed by Diptera with 3%. Other prey orders that showed a very low abundance (e.g., Araneae, Blattodea, Collembola and Coleoptera) were grouped in the category “others” and collectively represented 3% of available prey (Table 1 ). Species composition was very similar (82%) between the actual and potential prey according to the Morisita index. There was a higher consumption of certain ant species like Paratrechina sp. and Pseudomyrmex sp. when compared to their availability; nevertheless, we did not find a marked selectivity for any of the prey consumed (Table 2). Although the sampling period in our study was short compared to other descriptions of the diet composition in spiders, it sufficed to identify several prey species in the diet of O. concinnus, such as the dipterans, which had only been recorded for O. navus (Liznarova et al. 2013; Voss et al. 2007). The high capture frequency of ants by O. concinnus can be explained by the pronounced local abundance of this group compared to other prey. A similar tendency has been found in some theridiid spiders of the genus Latrodectus, which commonly include ants in their diet due to their high local abundance (Hodar & Sanchez-Pihero 2002; Salomon 2011). The high capture frequency of four ant species is explained by their availability; since Oecobius builds a web on the wall surface, the possibility of capturing crawling prey is higher than that of flying prey. Additionally, the predatory behavior of Oecobius, which consists of wrapping prey with silk and biting it once it is immobilized, allows them to capture dangerous prey like ants (Glatz 1967). Interestingly, some of the ant species consumed by O. concinnus, namely Camponotus sp. and Paratrechina sp., are considered invasive urban pests and show a wide pantropical distribution (Bolton 1995; Wilson 1973; Hansen & Klotz 2005) similar to that of O. concinnus (Santos & Gonzaga 2003; Brazil et al. 2005). For this reason we suspect that these ant species are a common prey for several populations of O. concinnus. The capture of other prey beside ants indicates that O. concinnus is not a strict myrmecophagous spider; nevertheless, the high capture frequency of ants suggests that they are an important prey in the diet of this species. This tendency is also shared by some spiders of the families Theridiidae and Salticidae, which do not prey exclusively on ants, but include them commonly in their diet (Cushing 2012). Other traits, such as locating the web next to places where ants are very common, are shared by O. concinnus and the occasional ant feeding spider Steatoda Julva ( Keyserling 1884; Holldobler 1970), suggesting that the presence or abundance of ants could influence the web location of the former species. Additional studies should explore this aspect. Since diet analysis by itself cannot reveal the complete trophic strategy of an organism, further experiments that analyze feeding choice and specialized predatory adaptations are needed to reveal whether the species is a trophic specialist. Future studies may assess whether the diet of O. concinnus varies locally like that of O. navus. ACKNOWLEDGMENTS We are indebted to Alejandro Brazeiro, Miguel Simo, Stano Pekar, Jose A. Hodar and Robert R. Jackson for literature and suggestions. David Wise provided very useful feedback on the paper’s structure and improved the English. Wolfgang Nentwig provided literature, and Adalberto Santos confirmed the identity of this species. Paola Gonzalez Vanegas and John Lapolla assisted with arthropod identification, and Miguel Hernandez helped with fieldwork. We also thank two anonymous referees for comments that improved this manuscript. Financial support was provided by the postgraduate program (PEDECIBA) and National Agency of Research and Innovation (ANII). LITERATURE CITED Bolton, B. 1995. A taxonomic and zoogeographical census of the extant ant taxa (Hymenoptera: Formieidae). Journal of Natural History 29:1037-1056. Brazil, T.K., L.M. Almeida-Silva, C.M. Pinto-Leitel, R.M. Lira-da- Silva, M.C. Lima Peres & A.D. Brescovit. 2005. Aranhas sinantropicas em tres bairros da cidade de Salvador, Bahia, Brasil (Arachnida, Araneae). Biota Neotropica 5:163-169. Cardoso, P., S. Pekar, R. Jocque & J.A. Coddington. 2011. Global patterns of guild composition and functional diversity of spiders. PLoS ONE 6:e2 1710. Table 2. — Savage’s selectivity analysis (Wi) of Oecobius concinnus Only one morphospecies from the family Chironomidae was found. over different prey types (ant subfamilies are indicated inside brackets). Prey species Captured (%) Available (%) Wi P Camponotus sp. (Formicinae) 27 30 0.92 0.70 Neivamyrmex sp.( Dolichoderinae) 27 45 0.60 0.40 Paratrechina sp. (Formicinae) 23 14 1.67 0.54 Pseudomyrmex sp. (Pseudoyrmicinae) 21 7 3.06 0.14 Chironomidae 1 4 0.33 0.76 GARCIA ET AL. DIET AND PREY OF OECOBIUS 201 Cushing, P.E. 2012. Spider-ant associations: an updated review of myrmecomorphy, myrmecophily, and myrmecophagy in spiders. Psyche 2012 (Art. ID ! 5 1989): 1-23. Glatz, L. 1967. Zur biologic und morphologic von Oecobius annulipes (Araneae: Oecobiidae). Zoomorphology 64:185-214. Hammer, O., D. Harper & P. Ryan. 2001. PAST: Paleontological statistics software for education and data analysis. Paleontologia Electronica 4:1-9. Hansen, L. & J. Klotz. 2005. Carpenter Ants of the United States and Canada, first edition. Comstock Publishing Associates, Ithaca, New York, USA. Hodar, J.A. & F. Sanchez-Pinero. 2002. Feeding habits of the black widow spider Latrodectus lilianae (Araneae: Theridiidae) in an arid zone of southeast Spain. Journal of Zoology 257:101-109. Holldobler, B. 1970. Steatoda fulva (Theridiidae), a spider that feeds on harvester ants. Psyche 77:202-208. Holldobler, B. & E.O. Wilson. 1990. The Ants. Springer- Verlag, Berlin, Germany. Huseynov, E.F.O., R.R. Jackson & F.R. Cross. 2008. The meaning of predatory specialization as illustrated by Aelurillus m-nigrum , an anteating jumping spider (Araneae: Salticidae) from Azerbaijan. Behavioural Processes 77:389-399. Jackson, R.R. & X.J. Nelson. 2012. Specialized exploitation of ants (Hymenoptera: Formicidae) by spiders (Araneae). Myrmecological News 17:33^19. Krebs, C.J. 1999. Ecological Methodology, second edition. Benjamin/ Cummings, Menlo Park, California, USA. Liznarova, E., L. Sentenska, L.F. Garcia, S. Pekar & C. Viera. 2013. Local trophic specialisation in a cosmopolitan spider (Araneae). Zoology 116:20-26. Manly, B.F.J., L.L. McDonald, D.L. Thomas, T.L. McDonald & W.P. Erickson. 2002. Resource Selection by Animals: Statistical Design and Analysis for Field Studies, second edition. Kluwer Academic Publishers, Boston, Massachusetts, USA. Pekar, S. 2004. Predatory behavior of two European ant-eating spiders (Araneae, Zodariidae). Journal of Arachnology 32:31-41. R Core Team. 2012. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Santos, A.J. & M.O. Gonzaga. 2003. On the spider genus Oecobius Lucas, 1846 in South America (Araneae, Oecobiidae). Journal of Natural History 37:239-252. Salomon, M. 2011. The natural diet of a polyphagous predator, Latrodectus hesperus (Araneae: Theridiidae), over one year. Journal of Arachnology 39:154-160. Voss, S.C., B.Y. Main & I.R. Dadour. 2007. Habitat preferences of urban wall spider Oecobius navus. Australian Journal of Entomol- ogy 46:261-268. Wilson, E.O. 1973. The ants of Easter Island and Juan Fernandez. Pacific Insects 15:285-287. Manuscript received 11 November 2013, revised 9 February 2014. 2014. The Journal of Arachnology 42:202-203 INSTRUCTIONS TO AUTHORS (revised August 2014) General: The Journal of Arachnology publishes scientific articles reporting novel and significant observations and data regarding any aspect of the biology of arachnid groups. Feature articles and short communications must be scientifically rigorous and report substantially new information. 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All review articles will be subject to the same review process as other submissions. Submission: Submissions must be sent electronically in Microsoft Word format (not PDF) to the Managing Editor of the Journal of Arachnology. Richard S. Vetter, Managing Editor, Department of Entomology, University of California, Riverside, CA USA 92521 [E-mail: rick.vetter@ucr.edu]. The entire manuscript should be submitted as one Word document. Figures, included in the Word document, should be at low resolution for the initial review. The Managing Editor will acknowledge receipt of the manuscript, assign it a manuscript number and forward it to an Associate Editor for the review process. Correspondence relating to manuscripts should be directed to the Associate Editor and should include the manuscript number. If the manuscript is accepted, the author will be asked to submit the final copy electronically to the Associate Editor. Submission of final illustrations is detailed below. Authors are expected to return revisions promptly. Revised manuscripts that are not returned in a reasonable time period (no longer than six months for minor revisions and one year for major revisions) will be considered new submissions. Voucher Specimens: Specimens of species used in your research should be deposited in a recognized scientific institu- tion. All type material must be deposited in a recognized collection/institution. FEATURE ARTICLES Title page. The title page includes the complete name, address, and telephone number of the corresponding author; a FAX number and electronic mail address if available; the title in sentence case, with no more than 65 characters and spaces per line in the title; each author’s name and address; and the running head. Running head. -The author’s surname(s) and an abbreviat- ed title should be typed in all capital letters and must not exceed 60 characters and spaces. The running head should be placed near the top of the title page. Abstract. — Length: < 250 words for Feature Articles; ^ 150 words for Short Communications. Keywords. — Give 3-5 appropriate keywords or phrases following the abstract. Keywords should not duplicate words in the title. Text. — Double-space text, tables, legends, etc. throughout. Except for titles and headers, all text should be left-justified. Add line numbers, continuous from the first page. Three levels of heads are used. • The first level (METHODS, RESULTS, etc.) is typed in capitals and centered on a separate line. • The second level head begins a paragraph with an indent and is separated from the text by a period and a dash. • The third level may or may not begin a paragraph but is italicized and separated from the text by a colon. Use only the metric system unless quoting text or refe- rencing collection data. If English measurements are used when referencing collection data, then metric equivalents should also be included parenthetically. All decimal fractions are indicated by a period (e.g., -0.123). Include geographic coordinates for collecting locales if possible, using one of the following formats: 0°12'32"S, 29°52'17"E or 0.2089°S, 29.8714°E. Citation of references in the text: Cite only papers already published or in press. Include within parentheses the surname of the author followed by the date of publication. A comma separates multiple citations by the same author(s) and a semicolon separates citations by different authors, e.g., (Smith 1970), (Jones 1988; Smith 1993), (Smith & Jones 1986, 1987; Jones et al. 1989). Include a letter of permission from any person who is cited as providing unpublished data in the form of a personal communication. Citation of taxa in the text: Include the complete taxonomic citation (author & year) for each arachnid taxon when it first appears in the abstract and text proper. For Araneae, this information can be found online at http://research.amnh.org/iz/ spiders/catalog/. For example, Araneus diadematus Clerck 1757. Citations for scorpions can be found in the Catalog of the Scorpions of the World (1758-1998) by V. Fet, W.D. Sissom, G. Lowe & M.E. Braunwalder. Citations for pseudoscorpions can be found at http://www.museum.wa.gov.au/catalogues/pseudoscorpions/. Citations for some species of Opiliones can be found in the Annotated Catalogue of the Laniatores of the New World (Arachnida, Opiliones ) by A.B. Kury. Citations for other arachnid orders can be found in Catalogue of the Smaller Arachnid Orders of the World by M.S. Harvey. Literature Cited. -Use the following style and formatting exactly as illustrated; include the full unabbreviated journal title. Personal web pages should not be included in Literature Cited. These can be cited within the text as (John Doe, pers. website) without the URL. Institutional websites may be 202 INSTRUCTIONS TO AUTHORS 203 included in Literature Cited. If a citation includes more than six authors, list the first six and add “et al.” to represent the others. Binford, G. 2013. The evolution of a toxic enzyme in sicariid spiders. Pp. 229-240. In Spider Ecophysiology. (W. Nentwig, ed.). Springer-Verlag, Heidelberg. Cushing, P.E., P. Casto, E.D. Knowlton, S. Royer, D. Laudier, D.D. Gaffin et al. 2014. Comparative morphology and functional significance of setae called papillae on the pedipalps of male camel spiders (Arachnida, Solifugae). Annals of the Entomological Society of America 107:510-520. Harvey, M.S. & G. Du Preez. 2014. A new troglobitic ideoroncid-pseudoscorpion ( Pseudoscorpiones: Ideoroncidae) from southern Africa. Journal of Arachnology 42:105-1 10. Platnick, N.I. 2014. The World Spider Catalog, Version 15.0. American Museum of Natural History, New York. Online at http://research.amnh.org/iz/spiders/catalog/ Roewer, C.F. 1954. Katalog der Araneae, Volume 2a. Institut Royal des Sciences Naturelles de Belgique, Bruxelles. Rubio, G.D., M.O. Arbino & P.E. Cushing. 2013. Ant mimicry in the spider Myrmecotypus iguazu (Araneae: Corinnidae), with notes about myrmecomorphy in spiders. Journal of Arachnology 41:395-399. Footnotes. — Footnotes are permitted only on the first printed page to indicate current address or other information concern- ing the author. All footnotes are placed together on a separate manuscript page. Tables and figures may not have footnotes. Taxonomic articles. — Consult a recent taxonomic article in the Journal of Arachnology for style or contact the Subject Editor for Taxonomy and Systematics. Papers containing original descriptions of focal arachnid taxa should be listed in the Literature Cited section. Tables. — Each table, with the legend above, should be placed on a separate manuscript page. Only horizontal lines (no more than three) should be included. Tables may not have footnotes; instead, include all information in the legend. Illustrations. — Original illustrations should be sent electron- ically as part of the Word document when the manuscript is submitted. Distribution maps should be considered figures and numbered consecutively with other figures. (Authors wishing to submit figures as hard copies should contact the Editor-in-Chief for specifications.) Al the submission and review stages, the resolution should be low while still allowing editors and reviewers to view figures effectively. Final illustrations must be submitted to the Editor-in-Chief, typically by e-mail or on a CD, to ensure that the electronic versions meet publication standards and that they match the printed copy. All figures should be 10-18 cm (4-7 inches) wide and no more than 23 cm (9 inches) high. The resolution should be at least 300 dpi (or ppi) for halftone or color figures and 1200 dpi for line drawings. A Guide to the Digital Art Specs for Allen Press is available as a PDF online at: http://allenpress.com/resources/library. At the discretion of the Editor-in-Chief, a figure can be rendered in color in the online version but in monochrome in the journal’s printed version, or in color in both versions if warranted by the figure’s context and content. Most figures will be reduced to single-column width (9 cm, 3.5 inches), but large plates can be printed up to two- columns width (18 cm, 7 inches). Address all questions concerning illustrations to the Editor- in-Chief of the Journal of Arachnology. Robert B, Suter, Editor-In-Chief Biology Department, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604-0731, USA [E-mail: suter@vassar.edu] Legends for illustrations should be placed together on the same page(s) and also with each illustration. Each plate must have only one legend, as indicated below: Figures 1-4. A-us x-us , male from Timbuktu. 1, Left leg; 2, Right chelicera; 3, Dorsal aspect of genitalia; 4, Ventral aspect of abdomen. Scale = 1.0 mm. The following alternate Figure numbering is also acceptable: Figures la-e. A-us x-us , male from Timbuktu, a. Left leg; b. Right chelicerae; c. Dorsal aspect of genitalia; d. Ventral aspect of abdomen. Scale = 1.0 mm. Assemble manuscript. The manuscript should appear in separate sections or pages in the following sequence: title page, abstract, text, tables with legends, figure legends, figures. Send entire manuscript, including figures, as one Microsoft Word document. Note: please downsize the figures if the document is too large to conveniently send by e-mail. Supplemental materials.— Authors may submit for online publication materials that importantly augment the contents of a manuscript. These may be audio files (e.g., .mp3, .m4a, .aif, .wav), video files (e.g., .mov, ,m4v, .flv, .avi), or Word documents (e.g., .doc, .docx) for large tables of data. Consult with the Editor in Chief if you are considering submitting other kinds of files. Audio and video files should be carefully edited before submission to eliminate leaders, trailers, and other extraneous content. Individual files may not exceed 10MB; no more than five files may be included as supplemental materials for a manuscript. Supplemental materials will be considered by reviewers and therefore must be submitted at the time of manuscript submission. Supplemental materials are published online at the discretion of the editors. Page charges, proofs and reprints. Page charges are voluntary, but non-members of AAS are strongly encouraged to pay in full or in part for their article ($75 / journal page). The author will be charged for excessive numbers of changes made in the proof pages. Hard copy or PDF reprints are available only from Allen Press and should be ordered when the author receives the proof pages. Allen Press will not accept reprint orders after the paper is published. The Journal of Arachnology also is available through www.bioone.org and www.jstor.org. Therefore, you can download the PDF version of your article from one of these sites if you or your institution is a member. PDFs of articles older than one year will be made freely available from the AAS website. SHORT COMMUNICATIONS Short Communications are usually limited to three journal pages, including tables and figures (11 or fewer double-spaced manuscript pages including Literature Cited; no more than 2 small figures or tables). Internal headings (METHODS, RESULTS, etc.) are omitted. Short communications must include an abstract and keywords. COVER ARTWORK Authors are encouraged to send high quality color photographs to the editor-in-chief to be considered for use on the cover. Images should be at least 300 dpi. CONTENTS Journal of Arachnology SMITHSONIAN LIBRARIES 3 9088 01790 2552 Volume 42 Number 2 Papers from the 19th International Congress of Arachnology (Taiwan) The effect of forest stand characteristics on spider diversity and species composition in deciduous-coniferous mixed forests by Ferenc Samu, Gabor Lengyel, Eva Szita, Andras Bidlo, & Peter Odor 135 Progress and prospects in taxonomy: what is our goal and are we ever going to reach it? by Bernhard A. Huber 142 Note from the Editors Participants in the 19th International Congress of Arachnology submitted only nine manuscripts for possible inclusion in this proceedings issue of the Journal of Arachnology . By comparison, that is less than a sixth of the number (62) that were submitted after the 17th ICA in Brazil in 2007 and a quarter of the number (36) that were submitted after the 18th ICA in Poland in 2010. The other papers in this issue (below) were received by the journal as non-ICA submissions. Featured Articles Discovery of two new species of eyeless spiders within a single Hispaniola cave by Trevor Bloom, Greta Binford, Lauren A. Esposito, Giraldo Alayon Garcia, Ian Peterson, Alex Nishida, Katy Loubet-Senear & Ingi Agnarsson 148 A new species of Charinus from Minas Gerais State, Brazil, with comments on its sexual dimorphism (Arachnida: Amblypygi: Charinidae) by Ana Caroline O.Vasconcelos, Alessandro P. L, Giupponi & Rodrigo L. Ferreira 155 Scorpion diversity of the Central Andes in Argentina by F. Fernandez Campon, S. Lagos Silnik & L. A. Fedeli 163 Juvenile experience and adult female mating preferences in two closely related Schizocosa species by Jenai M. Rutledge & George W. Uetz 170 Nocturnal, diurnal, crepuscular: activity assessments of Pisauridae and Lycosidae by Robert B. Suter & Kari Benson 178 Short Communications Submersion tolerance in a lakeshore population of Pardosa lapidicina (Araneae: Lycosidae) by Carl N. Keiser & Jonathan N. Pruitt 192 Microhabitat distribution of Drapetisca alteranda , a tree trunk specialist sheet web weaver (Araneae: Linyphiidae) by Michael L. Draney, Jennifer A. Hegnet, Ashley L. Johnson, Brooke C. Porter, Clarissa K. Justmann & Patrick S. Forsythe 195 Diet composition and prey selectivity by the spider Oecobius concinnus (Araneae: Oecobiidae) from Colombia by Luis Fernando Garcia, Mariangeles Lacava & Carmen Viera 199 Instructions to Authors . . 202 A- \ . ..... j ./ rh. f USERNAME: leach 14 PASSWORD: nephilal4