The intraspecific diversity of the few mygalomorph spiders in southern Appalachia has received considerable attention, revealing highly localized and deeply divergent populations and in some cases cryptic species. The araneomorph fauna of the region has received comparatively little study, due to its higher diversity, more tentative taxonomy, and perhaps perception that short-range endemicity might be lower. In this study, we examined this last assumption, surveying patterns of intraspecific diversity across Araneomorphae occurring in the leaf litter of high elevation spruce-fir sky islands of southern Appalachia, as revealed by population level metabarcoding. In most species, intraspecific haplotypic diversity, while high, revealed little geographic pattern, generally supporting assumptions of low regional endemicity. Of 50 spider species found in spruce-fir forest litter, more than 30 occur more widely, and showed little sign of subdivision even over major biogeographic features in the region, such as the French Broad River valley. By analyzing 10 of these well-sampled species with population genetic and phylogeographic methods, we found that only a few showed significant population level subdivisions. We suggest that the ballooning behavior of most immature araneomorph spiders is sufficiently frequent to overcome divergence of otherwise isolated populations, and that in those few exceptions the species are more specialized to particular microhabitats in the spruce-fir forest and such unpredictable dispersal may have been selected against.

Species differ in their reproductive abilities, which may affect their success. In southwest Ohio, populations of Pholcus phalangioides (Fuesslin, 1775) (Araneae: Pholcidae) have largely been replaced by Pholcus manueli Gertsch, 1937 (Araneae: Pholcidae). We suspected that differences in reproductive output underpinned the success of P. manueli. We documented the reproductive success of both species in the laboratory. Female P. phalangioides mated more readily and were more likely to produce eggsacs than P. manueli, but the timing of eggsac production and spiderling emergence were similar. The eggsacs of P. phalangioides contained smaller numbers of larger eggs but similar numbers of spiderlings emerged from the sacs of both species. We uncovered a negative relationship between egg size and number for P. phalangioides, but not for P. manueli. Our results do not explain the relative success of P. manueli, however, we have uncovered differences in the reproductive strategies utilized by these ecologically-similar congeners.

We present the first recorded description of females of the species Dinorhax rostrumpsittaci (Simon, 1877) from solifugae specimens obtained from southern Vietnam. As a result of DNA barcoding using males identified as D. rostrumpsittaci and unidentified females, these female specimens made a highly supported cluster with male D. rostrumpsittaci. Hereby, we describe the female D. rostrumpsittaci and its natural habitats.

Scorpions fluoresce a bright green when under ultraviolet light, but the functional significance of the fluorescence is still unknown. A major challenge in studying scorpion fluorescence is the lack of efficient methods for testing the behavioral photosensitivity of scorpions. We have modified previous assays to produce a more sensitive testing device. The apparatus consists of a circular track made of a small Petri dish nested inside a larger one, with an LED shining from the inner chamber across a small sector of the track. We monitored the scorpions' movements in the arenas under three light wavelengths: ultraviolet (399 nm), yellow-green (566 nm), and red (630 nm); all wavelengths were matched to a nighttime light intensity (0.01 irradians). We also tracked each animal's movements in the absence of light as a control. The animals were attracted to 399 and 566 nm light and also showed some attraction to 630 nm. Furthermore, earlier studies suggest that scorpion photoreceptors form a homogeneous population that has been physiologically shown to be maximally sensitive to green wavelengths. We hypothesize that the photoreceptor population might be somewhat responsive to red light too, suggesting that the photoreceptors may respond to a broad spectrum of light or that the photoreceptor population may not be as homogeneous as previously thought. The strong response to UV light, as has been seen in other behavioral assays, remains enigmatic. Overall, this new assay is more sensitive than previous assays for detecting scorpion photoresponse and will be useful for future studies.

Ecologists are often required to accurately estimate the number of individuals residing in groups of variable sizes inside opaque shelters. Here, we have used x-rays as a non-destructive solution to this problem in social spiders which reside within collectively built opaque, silken, nest-like retreats. Social spiders are model systems for understanding social organization, collective behaviours and population genetics of inbred populations. Such studies often require an accurate determination of the number of individuals, developmental stages and orientation of individuals within the colony which is difficult without compromising the integrity of their retreat or affecting colony behaviour. We demonstrate the effectiveness of x-rays in accurately estimating colony size in the social spider Stegodyphus sarasinorum Karsch, 1892 (Eresidae). This method can also be applied to evaluate body sizes, developmental stages and individual orientation within the colony. We show that this technique does not alter spider prey-capture behaviour or short-term survival compared to control colonies.

Gonyleptes curvipes Kollar, in C.L. Koch, 1839 has taxonomic problems: it is a primary junior homonym of Gonyleptes curvipes Guérin-Méneville, 1837; the holotype of G. curvipes Kollar was cited twice by Roewer (1913) under two genera, one being a misidentification of an undescribed species and a new combination under Discocyrtus Holmberg, 1878; Koch labeled another unreported specimen as Gonyleptes curvipes. However, this specimen belongs to a species described later by Roewer as D. crenulatus Roewer, 1913. In 2003, Kury transferred G. curvipes sensu Roewer to Discocyrtus and, to avoid homonymic collision with D. curvipes sensu Roewer, proposed the new name D. confusus as a replacement name. Discocyrtus confusus was later considered an invalid replacement name and was used to newly describe the species named by Kollar and Koch. Discocyrtus flavigranulatus B. Soares, 1944 is here considered a new junior subjective synonym of G. curvipes Kollar, but which is the next oldest available synonym. Discocyrtus confusus thus also becomes a junior synonym of D. flavigranulatus. Here we discuss the history and identity of three species of Discocyrtus: D. flavigranulatus B. Soares, 1944; D. crenulatus Roewer, 1913; and D. fenax sp. nov. from Santa Catarina state, Brazil (misidentified by Roewer as D. curvipes).

We describe the remarkable egg sac of Benoitia lepida (O.P.-Cambridge, 1876) (Agelenidae) from the Negev Desert, Israel. It consists of four layers: (from outside) a papery envelope, an outer loose silk layer, a “dirt layer”, and an inner flocculent silk layer surrounding the eggs. The dirt layer consists of loess soil, and may include stones, snail shells, or twigs from the surroundings. Some sacs hang from a silken string over the female's web sheet, attached to barrier threads or overhanging vegetation. In these “hanging sacs”, the outer papery wall is shiny white and covers the inner layers completely. Other sacs (“attached sacs”) are attached to a top branch of a shrub, away from the female's web. These sacs often have little or no outer papery envelope; the outer silk wrapping encloses the branch, and the sac may be dull brown in color. We studied the species at two sites; at one the hanging sac type predominated, while at the other the attached type was most common. A field experiment revealed that the dirt layer is effective in protecting the sacs against predation from ants but had no effect on spider predators of the egg sacs.

The wasp spider Argiope bruennichi (Scopoli, 1772) is of Mediterranean-Pontian origin, but for decades it has been expanding northwards, including into the territory of Poland. Based on well-documented expansion records, we can distinguish “old” (south-eastern and south-western) and “new” populations (north-eastern), respectively, from the 1930s to the 2000s. In Poland, some populations of A. bruennichi were expected to be more genetically isolated from others, due to distance effects or differential times of arrival. We evaluated whether the oldest populations were in a state of Hardy-Weinberg equilibrium (HWE), and whether recently founded populations were in an expansion phase. Specimens of A. bruennichi (n = 184) were collected at six localities in Poland and single sampling sites in Italy and Japan. Nine microsatellite loci were amplified although only five were useful in the final analyses. Based on the genotypes obtained, we estimated basic measures of genetic diversity and tested for deviation from HWE. The results showed a low level of polymorphism amongst the investigated markers, and accordingly, we found a low genetic diversity in populations. Only populations from Italy and Japan, and one population from Poland, were in HWE. The level of genetic differentiation among sampling sites from Poland was also very low. The high dispersal ability of the wasp spider appears to have facilitated high gene flow among populations. The peripheral and recently settled populations were characterized by the highest heterozygosity and the lowest inbreeding coefficient (FIS). The remaining Polish populations are therefore still in the expansion phase, as indicated by deviations from HWE.

A new species of the lycosid subfamily Evippinae is introduced and preliminarily assigned to the genus Evippomma Roewer, 1959. It was found in the Erg Chebbi Desert in Morocco. Evippomma rechenbergi sp. nov. is a wolf spider with unusual morphological and behavioural features, e.g., having exceptional scales on most of its body and carrying sand by interconnecting sand grains with silk threads. A detailed description and delimitation of this species is given. Its genus-affiliation is found uncertain. We conclude that a comprehensive revision and phylogenetic study of all African genera of the subfamily Evippinae are needed to enable unambiguous identification (including unambiguous genus identification) and for a better understanding of phylogenetic relationships among these genera.

Based on studies of adult behavior, the desert spider Agelenopsis aperta (Gertsch, 1934) is considered exemplary of a species exhibiting an aggressive syndrome. This study offers a first examination of the nature of interactions that juvenile A. aperta engage in during the period when sibs are clustered on a group web. We test the hypothesis that early instar A. aperta lack the aggressiveness noted for older instars. Our data set is comprised of observations of five weekly feedings offered to 818 sibling pairs, constituting an average of 4.6 replicate sib pairs from each of 174 families. At each weekly feeding, a worker termite was offered to each sib in the shared container in which they had built web retreats. We observed no cooperative foraging during the course of these feedings. Rather, most families exhibited a mix of independent foraging and non-injurious contests over prey. We present a brief overview of the occurrence and initiation of contests over prey, with particular reference to the weekly feeding in which contests first occur versus the feeding in which a seminal contest takes place (i.e., where sibs earn permanent winner versus loser status).