A third troglobitic species of Brazil is described from three specimens collected within Gruta da Morena, located in the municipal district of Cordisburgo, Minas Gerais. Eukoenenia sagarana new species (Palpigradi: Eukoeneniidae) is highly adapted to subterranean environments, corresponding to the most troglomorphic Palpigradi species described to date. This new species is very close to E. maquinensis Souza & Ferreira 2010, a troglobitic species recently described from Gruta de Maquiné, located in the same municipal district. The differences and similarities between these two species and between E. sagarana and other species of Eukoenenia are presented.

Three new species of the family Anapidae are reported from caves and tropical rainforest of southern China: Gaiziapis encunensis, Minanapis menglunensis and Sinanapis longituba. The genus Minanapis is recorded for the first time from China.

A prior study of molecular phylogenetic relationships in southern Appalachian Hypochilus taxa revealed unusually high intraspecific mitochondrial sequence divergences, but was limited by small intraspecific sample sizes. A subsequent in-depth population genetic study focused on a single species (H. thorelli Marx 1888), revealing genetic patterns consistent with extremely limited female-based gene flow among rock-outcrop limited populations. Here we extend the study of mitochondrial population genetic structuring to four remaining Appalachian Hypochilus species. Genetic inferences are based on a sample of COI mitochondrial sequences generated for over 250 specimens from 85 sampled locations. This geographic sample comprehensively covers the geographic distributions of all described taxa. Phylogenetic, network-based, and genealogical sorting index analyses reveal ubiquitous genetic structuring in all Hypochilus taxa. A majority of sampled locations possess limited genetic variation, with site-specific haplotypes forming genealogically exclusive “microclades”, consistent with limited female-based gene flow at the spatial scales sampled. At deeper phylogenetic levels, four of five described species are recovered as monophyletic on mitochondrial gene trees. Hypochilus pococki Platnick 1987 is recovered as paraphyletic, and is fragmented into five genetically divergent, allopatric phylogroups. These phylogroups, and multiple clades within one of the H. pococki phylogroups, are also recovered as distinct clusters in a generalized mixed Yule-coalescent (GMYC) analysis, suggesting the possibility of multiple cryptic species in the Appalachian fauna. However, a qualitative survey of male palpal variation fails to reveal morphological differences that distinguish these highly divergent genetic lineages. We suggest that a nuclear gene tree perspective is ultimately needed to resolve this contrast.

The new genus Tigrosa is established for five Nearctic species originally described in the genus Lycosa Latreille 1804. Four of the species are transferred from Hogna Simon 1885: H. annexa (Chamberlin & Ivie 1944), H. aspersa, (Hentz 1844), H. grandis (Banks 1894) and H. helluo (Walckenaer 1837). The remaining species, Allocosa georgicola (Walckenaer 1837) is transferred from Allocosa Banks 1900. The presumed synapomorphy that supports Tigrosa is the color pattern on the dorsum of the cephalothorax, which is described and illustrated. In addition to their distinct color pattern, Tigrosa species are very similar in characteristics of the male palpus and epigynum, details of the eye arrangement, leg length in relation to body dimensions, as well as foraging habits. Comparisons made between Hogna, as defined by the type species H. radiata, Latreille 1817, and Tigrosa, as defined in this paper, demonstrate distinct differences in dorsal color pattern, structure of the epigynum, dimensions of the eye rows, color pattern of the venter and habitat preferences.

The brown widow spider, Latrodectus geometricus C. L. Koch 1841, is non-native to North America and has experienced an explosive range expansion in the first decade of the 21^st century. Previously restricted to peninsular Florida, it is now well established in the southeastern United States and southern California. In southern California, brown widow spiders have become ubiquitous around urban homes and are well known to the general public because of their high numbers and distinctive spiked egg sacs. Several insects attack egg sacs of the native western black widow, L. hesperus Chamberlin & Ivie 1935, as either parasitoids or egg predators. We investigated whether and to what degree these insects would attack brown widow egg sacs. We dissected 3,739 brown widow egg sacs finding evidence of the chloropid fly, Pseudogaurax signatus (Loew 1876) in 2.0% and wasp parasitoids in 0.4% of the sacs. For comparison, we also dissected 263 western black widow egg sacs with P. signatus showing a higher level of predation (6.1%). Other brown widow sac inhabitants included larvae and adults of dermestid beetles, psocids, and lepidopterans, which are probably scavengers or incidental occupants. The overall impact of the recorded predators and parasitoids is too low to explore the possibility of a biological control program. Additionally, due to the relatively low number of predators/parasitoids in brown widow egg sacs and the entanglement of small arthropods on the outer surface, we speculate that the spiked egg sac surface might serve as an effective barrier to most predators and parasitoids.

We investigated abundance and web characteristics (web elevation and spiral area) of the spiny orb weavers Micrathena gracilis (Walckenaer 1805) and Micrathena mitrata (Hentz 1850) using transect surveys in oak-hickory forest stands in west-central Illinois. Surveys resulted in 153 collected individuals or observations of adult females (70 M. gracilis and 83 M. mitrata). Peak abundance of both species occurred in late July, with a density of 0.03 females per m² for each species. Web spiral area and web elevation were both greater for M. gracilis than M. mitrata. Micrathena mitrata web spiral area was larger in plots in which spiders had been previously removed than in plots without removal. These results suggest that the two species have different vegetation structure or microclimate preferences, and may respond to availability of unoccupied habitat differently.

Habitat structure is of great importance for the distribution and abundance of various organisms. Spiders are especially sensitive to structural features of their environment. Although spiders are influenced by habitat structure, it remains unclear whether spiders respond to architecture, to differences in prey availability associated with different architectures, or both. Here, we investigated the effects of shrub architecture and prey availability and their interactions on a spider community in a shrub-steppe environment in northern Utah, USA. Big sagebrush shrubs, matched by size, were randomly assigned to six experimental treatments: two levels of prey attractant (shrubs were either baited or not baited) and three levels of foliage density (low, natural/control, or high). We found that spider abundance and species richness were affected by both prey availability and shrub architecture, while variation in spider species diversity (Shannon-Wiener index) was governed by changes in shrub architecture. Spider species and family compositions were also associated with changes in shrub architecture, although guild composition was not. We discuss the implications and limitations of these findings and present suggestions for future research.

We examined differences in predatory behavior between two age groups (newly hatched spiders vs. spiders over 12 weeks old) of Yllenus arenarius Menge 1868 (Araneae: Salticidae). The spiders hunted three prey taxa (leafhoppers, caterpillars and thrips) for which they possess pre-programmed predatory behavior. The aim of the study was to check the influence of age and experience on pre-programmed predatory behavior and predatory success. Age-dependent changes occurred in four aspects of predation: direction of approach, mode of approach, distance of attack and predatory success.

Many species use autotomy, the self-amputation of an appendage, as a last-gasp method to escape a predator. Although this behavior can have immediate survival benefits, it can also negatively affect future survival or reproduction. The wolf spider Pardosa valens Barnes 1959 occurs along small mountain streams in southeastern Arizona, where it moves both on cobble along the stream and on top of the water's surface. Autotomy of legs is common in this species, and we hypothesized that such leg loss could lead to decreased sprint speed in both terrestrial and aquatic locomotion. We examined burst speed in the laboratory on artificial terrestrial and aquatic racetracks during 2005 (both males and females) and 2006 (females only). In 2005 terrestrial trials, intact spiders were faster than autotomized spiders, but there was no effect of sex on speed. In contrast, 2005 aquatic trials revealed that females ran faster than males, but that autotomy had a negative impact on the speed of females only. Additionally, female spiders generally ran faster on the terrestrial track later in the day than earlier in the day, suggesting that environmental variables such as temperature may have some influence on spider locomotion. Males were less likely to run on water than were females, and ran shorter distances when they did run. Results for females during 2006 also showed a decline in speed with autotomy, and an increase during later trials, although the results were weaker than during 2005, with only the aquatic trials showing a significant difference. These results suggest that leg autotomy in this spider does have a cost, but that the magnitude of this cost depends on aspects of the spider (e.g., sex) and habitat (e.g., substrate and environmental conditions).

Behavioral evidence suggests that, in some scorpion species, females deposit a pheromone that attracts mates. To date, however, no pheromone has been identified. The goal of our study was to isolate a pheromone from female desert grassland scorpions, Paruroctonus utahensis (Williams, 1968) (Scorpiones:Vaejovidae). We took in situ cuticular washes from female P. utahensis in a chloroform-methanol solution; the extract stratified into aqueous and organic layers. In controlled laboratory experiments, most males exposed to female extract (aqueous and organic fractions combined) exhibited pre-courtship behavior, whereas those exposed to the solvent control (2∶1 chloroform-methanol) showed no change in behavior. When extract fractions were separately tested, males initiated pre-courtship behavior when exposed to the organic fraction but not when exposed to the aqueous fraction. These data are the first experimental evidence of a female pheromone in this species and are important early steps toward characterizing any scorpion pheromone.

Coalition military bases in Afghanistan are increasing in area, infrastructure and population due to increased military efforts. From 2004 to 2010, a 40-hectare base in Ghazni, Afghanistan transitioned from a montane shrubland to a small, modern “village.” This shift comprised an over 50-fold increase in hardcover and a 20-fold increase in the human population. I searched the base with UV light (n  =  43.6 h) for scorpions, especially Mesobuthus Vachon 1950, an established, opportunistic scorpion found in Ghazni City, 5 km north. I completed my searches along two tracks (> 5 km total length) and considered all habitats for this scorpion. Anthropogenic microhabitats comprised concrete walls, concrete barriers, gabions or sandbags, each in contact with a dirt or gravel substrate (eight possible); all were thermally appealing (mean  =  2.3°C warmer than ambient temperature). Despite the population of Mesobuthus caucasicus Nordmann 1840 in Ghazni City and the increase in thermally attractive microhabitats on the base, I found no scorpions. I propose that the rapid anthropogenic change due to base improvements outpaces the capacity of this scorpion to disperse to a new, albeit satisfactory, environment. Here, I report my observations of scorpion diversity and abundance in east-central Afghanistan and the Hindu Kush Mountains, with a focus on the impact of increasing anthropogenic change upon the environment.

In general, spiders that build long-lasting webs invest a larger amount of silk and consequently a larger amount of energy in their construction than those species that build ephemeral webs. It is expected that spiders that build long-lasting webs choose rigid substrates for web construction to help preserve their investment. I experimentally tested this prediction by confining Cyrtophora citricola (Forsskål 1775) (Coddington 1989) spiders (n  =  32) in containers provided with firm and unstable substrates for the spiders to construct their webs. This experiment confirms that C. citricola strongly prefers firm substrates to which to attach its web when it must choose between a firm and an unstable substrate.

Microstigmatidae are small ground-dwelling and free-living spiders. The present study reports on the copulatory behavior of Xenonemesia platensis Goloboff 1989, constituting the first report on sexual behavior of the Microstigmatidae. Our findings in X. platensis did not show evidence of pheromones associated with silk. The courtship behavioral units of males was comprised of quivers by legs I and II, brusque movements of the palps, and leg tapping with legs II. During mating, a novel courtship behavior by males was observed that consisted of tapping and scraping with legs II on the female legs. The present study not only gives a description of mating behavior in Microstigmatidae for the first time, but also reports strong evidence of nongenital copulatory courtship activity in mygalomorph spiders.

We present the first record and description of the gregarious behavior of the Neotropical harvestmen Serracutisoma proximum (Mello-Leitão 1922) and Serracutisoma spelaeum (Mello-Leitão 1933) (Opiliones: Gonyleptidae: Goniosomatinae) (DaSilva & Gnaspini 2010). We followed and described the pattern of these aggregations over a period of 17 months in a cave in southeastern Brazil. Individuals of the two species aggregated with both conspecifics and heterospecifics during the non-reproductive season (i.e., from October to March, the cool and dry season). Aggregations contained up to 81 individuals, usually with a female-biased adult sex ratio. Multispecific aggregations were usually composed mainly of representatives of one of the two species, suggesting that although these species also aggregate with heterospecifics, there is a preference for aggregating with conspecifics. This study provides novel information on the social behavior of harvestmen, specifically regarding the composition of multispecific aggregations.

We describe multiple observations of epizoic cyanobacteria occurring on external surfaces of a species of sclerosomatid harvestman (Prionostemma sp.) in Costa Rica. In the field we collected four adults (three males, one female) that had green films growing upon the dorsal surfaces of the carapace and abdominal scutum. Examination by SEM revealed dense clusters of what appeared to be small prokaryotic cells (1–5 µm in diameter) covering the external surfaces of the carapace, abdominal scutum and coxae. We extracted DNA from the films of two specimens. The DNA was used as a template to amplify the intergenic spacer region (IGS) between the beta and alpha phycocyanin subunits (a signature DNA sequence, unique to cyanobacteria) by PCR. We successfully amplified an approximately 700 base pair product using DNA extracted from the film and did not obtain any product from the harvestman lacking the film. Our observation represents the second confirmed occurrence of epizoic cyanobacteria on Neotropical harvestmen. This is the first report of cyanobacteria associated with a sclerosomatid anywhere and the first known case from Central America.