We survey spiders from 43 families, 62 genera, and three arachnid outgroups for the presence and diversity of elongated pedicillate setae (EPS)—a complex system of probably sensory setae hitherto undocumented outside Theridiidae. Although not present in all spiders, these setae are sufficiently widespread to suggest they are primitively present in the order. Because they are absent in related arachnids, they appear to be a synapomorphy of spiders. Based on the morphology and orientation of these setae, it has been suggested that they supplement abdominal slit sensilla in proprioception, documenting the position and movement of the abdomen relative to the cephalothorax. Although still poorly known, the presence and distribution of these setae are informative at lower and higher phylogenetic levels.

Troglohyphantes bornensis, a new species from the western Italian Alps, is here described. According to the features of the male palp and female epigynum the new species can be assigned to Fage's III Group, Deeleman-Reinhold's marqueti group and Pesarini's microcymbium complex. All specimens were collected in the stony debris of Pugnetto caves (province of Turin, Italy), a calcschist cave complex, formerly studied by biospeleologists for the presence of several endemic species. All caves have openings into beech woods at an elevation of approximately 800 m.

Nine species of the genus Dysdera were found to occur in central Europe: D. adriatica Kulczyński 1897, D. crocata Koch 1838, D. dubrovninnii Deeleman-Reinhold 1988, D. erythrina (Walckenaer 1802), D. ninnii Canestrini 1868, D. hungarica Kulczyński 1897, D. lantosquensis Simon 1882, D. longirostris Doblika 1853, and D. taurica Charitonov 1956. Two species, D. dubrovninnii and D. lantosquensis, are newly recorded from central Europe. The original description of D. hombergi (Scopoli 1763), the name used for a common species of the genus Harpactea, probably refers to D. ninnii. We retain the name D. ninnii as a nomen protectum. Dysdera hamulata Kulczyński 1897 appears to be a junior synonym of D. maurusia Thorell 1873. This North African species probably does not occur in central Europe, and a previous record from Slovakia is probably based on mislabeled material. A review of all species of Dysdera named from outside the Palearctic region demonstrated that D. australiensis Rainbow 1900 and D. magna Keyserling 1877 are junior synonyms of D. crocata, and that D. bicolor Tatzanovski 1874 and D. solers Walckenaer 1837 are erroneously placed in the genus Dysdera; the former is likely to be an oonopid and the latter a caponiid. In central Europe, Dysdera spiders prefer xerothermic forests, particularly sites enriched by calcium. All species probably have biennal life-cycles. The karyotype of males of seven species were examined, and diploid chromosome numbers were found to be extraordinarily variable, ranging from 9 (D. crocata) to 40 (D. longirostris). Karyotypes consist of holocentric chromosomes.

The venoniine wolf spider genus Allotrochosina Roewer 1960 currently includes two species, A. schauinslandi Simon 1899 from New Zealand (type species) and A. karri Vink 2001 from Western Australia. A third species of this genus, A. walesiana new species from New South Wales, Australia, is here described. Some differences in genital morphology of A. walesiana in comparison to A. schauinslandi and A. karri in combination with a misinterpretation of genitalic characters in previous treatments of the genus require a new diagnosis for Allotrochosina. The genus is characterized by the presence of a distinct apical process on the embolic division of the male pedipalp. Allotrochosina walesiana appears to be winter mature since adult spiders have only been found between June and October. Additional records of A. karri, which was previously only known from the type locality, Crowea in southwest Western Australia, extend the known distribution by more than 600 km to the North.

Dasychernes inquilinus Chamberlin 1929, the type species of the genus, was described from specimens taken from colonies of the stingless honey bee Melipona salti Schwarz 1932 (Hymenoptera, Apidae). For the first time since its description, we report D. inquilinus from a nest of M. compressipes (Fabricius 1804) and, to document intraspecific variation, we also provide descriptive notes on the female pedipalp and leg. We discuss the rareness of D. inquilinus and summarize published information on pseudoscorpion-bee relationships. We found a total of 15 pseudoscorpion species (six genera in three families) reported from colonies of three stingless bee species and two honey bee species. The role of pseudoscorpions within bee nests is still poorly known. Like our notes on D. inquilinus, most records of pseudoscorpion-bee relationships are sporadic observations, sparsely reported in the literature.

Newly emerged crab spiderlings Misumena vatia (Clerck 1757) that recruit to goldenrod Solidago spp. inflorescences are subject to predation by small jumping spiders (Salticidae), principal among them being middle-instar Pelegrina insignis (Banks 1892). I censused goldenrod inflorescences to determine whether the distribution and abundance of crab spiderlings and small jumping spiders were related to one other. The censuses demonstrated a modest negative relationship in the presence of the two species to each other on the inflorescences of goldenrod clones. On inflorescences cleared of spiders and stocked with 20 dyed crab spiderlings, a strongly negative relationship occurred between numbers of recruiting jumping spiders and crab spiderlings on the first two days, but on the third and fourth days a significant positive relationship occurred. A similar pattern occurred on clones cleared of spiders and stocked with 20 spiderlings and three jumping spiders, but the shift to a positive relationship took place after a single day. This shift in behavior apparently occurred after the spiderlings found satisfactory hiding and hunting sites. Seventeen of the 39 jumping spiders captured at these sites during the two experiments had dye on their mouthparts, indicating that they had captured crab spiderlings during this time.

In this study we hypothesized that Grammostola rosea Walckenaer 1837, an active predator of large size that depends on its two paired book lungs for respiration, would have a refined low energy strategy based on its thin air-hemolymph barrier. The morphology of book lungs and the oxygen consumption at 20° and 30° C under normal and starvation conditions were studied. The oxygen consumption was low compared to that expected for spiders from the allometric relationship, 0.027 ± 0.01 ml O₂ g⁻¹ h⁻¹ (average ± standard deviation), and it was depressed at 30° C under starvation. The harmonic mean thickness of the air-hemolymph barrier was 0.14 ± 0.03 µm, the respiratory surface density was 122.99 ± 35.84 mm⁻¹, and the book lung volume ranged from 12.2 to 37.5 mm³. With these parameters a high oxygen diffusion capacity was estimated. The combination of low resting oxygen consumption and high pulmonary oxygen conductance results in very low gradients of partial oxygen pressures across the air-hemolymph barrier (0.12–0.16 kPa) required to satisfy the resting oxygen demands.

Salticid spiders are a tractable group for studies of learning. We presented Phidippus princeps Peckham & Peckham 1883 with the challenging task of associating prey with color cues in a T-maze. Experimental spiders were given the opportunity to learn that a cricket was hidden behind a block of a particular color. To eliminate the use of other cues, we randomly assigned both block position within the maze, and maze location within the room. For control spiders, no cues predicted the location of prey. We gave spiders two blocks of trials. Each block consisted of four training trials followed by a probe trial in which no prey was present. Trials lasted an hour, and spiders were given one trial per day. Not all spiders were successful in finding the prey during training trials. In the first probe trial, there was no evidence of learning: there was no effect of treatment, the number of successful training trials, or their interaction on which block the spiders chose first. In the second probe trial, there was a significant interaction between treatment and number of successful training trials: experimental-group spiders with a greater number of successful training trials were more likely to choose the correct block in the probe trial. This study demonstrates that P. princeps can learn the location of prey by color cues alone, a challenging task, and adds to the growing literature on learning in spiders.

Twenty-two interactions between males of Loxosceles gaucho Gertsch 1967 were investigated in order to study its intrasexual interactions and level of aggressiveness. Aggression by lunges or bites was observed in just 22.7% of the trials and three behaviors were identified as aggression-attenuating mechanisms: a hug; fleeing, and a postural pattern (POS). Interactions took place in 59.1% of the trials and the pairs interacted using one or two behavioral patterns (vibratory and/or postural). The vibratory pattern (VIB) consisted of foreleg vibration, palpal drumming, and abdominal pulsation and was used by both resident and intruder opponents. The postural pattern (POS) was used exclusively by resident males and it was similar to the behavioral pattern of sexually receptive L. gaucho females; in these cases the intruder male responded using the VIB. In conclusion, the interaction between adult L. gaucho males is usually non-aggressive. The behaviors described in this study possibly promote group-living and help to explain the gregarious populations of recluse spiders. Intra-specific sexual mimicry can occur in these interactions, but this hypothesis requires further investigation.

Generalist predators hunt a wide range of prey that possess various characteristics affecting the predators' hunting success (e.g., size, ability to detect the threat and defend against it, potential for escape). Therefore, it can be expected that the predator should flexibly react to different prey characteristics, hunting them in prey-specific ways. For a stalking predator a crucial prey feature is its ability to escape. In this study, the alternative prey-catching tactics of a dune-dwelling salticid Yllenus arenarius Menge 1868 were analyzed. Four naturally eaten prey taxa, two with a high ability to escape (Homoptera, Orthoptera) and two with a low ability to escape (Thysanoptera, larvae of Lepidoptera), were used. Numerous differences found between the tactics indicate that Y. arenarius can not only distinguish between different types of prey, but can also employ specific tactics to catch them. The tactics belong to a conditional strategy and are manifested in alternative: a) direction of approach, b) speed of approach, and c) other prey specific behaviors.

Birds are common predators of arthropods in many ecosystems but their impact on spiders has not been assessed. Therefore, the experimental evidence for bird predation effects on spider populations was examined. In particular, the present review focuses on the questions: what are the ecological mechanisms and what are the evolutionary consequences? Data from 17 field experiments, mainly in forest ecosystems, showed that spider communities were often significantly affected by bird predation. Comparisons of experimental effects were based on the ratio of mean density on experimentally enclosed vegetation and on controls. In 27 tests, a significant effect was detected (mean ratio 3.03) but in 9 tests the effect was non-significant (mean ratio 1.03). Furthermore, field experimental studies on bird predation effects on certain spider species or certain genera were reviewed. In three investigations, significant predation effects were found on agelenid, linyphiid and theridiid spiders but there were no significant effects on lycosids. Selective bird predation on large individuals has been shown in studies on spider communities and single species. Data on bird predation effects on species richness were lacking although impact on large species was expected to be important. Three field experiments showed that different spider families may experience differences in bird predation pressure. An aviary experiment showed that frequently moving spiders had a higher risk of predation than sedentary individuals, but the evidence from field experiments supporting the hypothesis of high predation pressure on moving spiders was limited. This included sex-specific differences in size and movement, although at least one experiment showed that males had higher winter mortality than females. One experiment showed that bird predation can affect anti-predator behavior. In conclusion, the present evidence showed that bird predation on spiders in several contrasting forest ecosystems is strong. However, there are many hypotheses regarding bird predation on spider populations that should be examined in future field experiments.

Nephila clavipes (Linnaeus 1767) and N. pilipes (Fabricius 1793) juveniles exposed to a novel and potentially dangerous prey item frequently attack using thrown silk. To quantify the frequency with which N. clavipes opt to use thrown silk, naïve hand-reared small N. clavipes juvenile females were observed attacking a new prey type, stingless bees. Repeated exposure to the stingless bees suggests that the spiders incorporate prior experience into prey attack strategies, as experienced spiders attacked using the more usual Nephila long-bite.

The type specimens of ten of Nicolet's species of jumping spider from Chile were examined. In this paper we present seven new synonymies and two new combinations for these nominal species as well as a redescription and illustrations where necessary. Attus iricolor Nicolet 1849, Attus scalaris Nicolet 1849, Attus superbus Nicolet 1849 and Attus zonarius Nicolet 1849 are synonymized with Dendryphantes mordax (C.L. Koch 1846); Euophrys quilpuensis Simon 1901, Attus vanus Nicolet 1849 and Attus vestitus Nicolet 1849 are synonymized with Euophrys rusticana (Nicolet 1849) comb. nov.; Attus legibilis Nicolet 1849 is tentatively transfered to Dendryphantes C.L. Koch 1837.

We describe a simple protocol for digesting the internal soft tissues of spiders using an enzyme complex known as pancreatin. This technique is preferred over digestions with caustic agents because it better preserves the cuticle surface, allowing its study by means of scanning electron or transmitted light microscopy. In addition, we describe a technique for mounting spider body parts for scanning electron microscopy using an acryloid polymer.

The female of Camptocosa texana Dondale, Jiménez & Nieto 2005 is described from Arizona. Females of C. texana are compared to those of C. parallela (Banks 1898), which differ from C. texana females in the color morphology of the carapace and the shape of the median septum.

This study reports on some observations on the biology of the Central Asian solifuge, Galeodes caspius subfuscus Birula 1937. Solifuges were active only during summer months. At other times, they were found in burrows located in sandy soils on southeast facing slopes. They were strictly nocturnal in their activity patterns. Small specimens (juveniles) were observed to forage only in the bush using a “sit-and-wait” strategy, while large specimens (subadults and adults) foraged actively only upon the ground. Their prey included various insects including Trichoptera, Coleoptera, and Ensifera. Mating behavior appeared aggressive as several females consumed males either before or after copulation. The mating is described in detail. After mating, females deposited eggs in a burrow and guarded them, presumably until hatching.

The putative fossil whipscorpion Thelyphonus hadleyi Pierce 1945 (Arachnida: Uropygi) from the middle to late Miocene Monterey Formation of Cabrillo Beach, San Pedro, California is reassessed. It is shown here to be nothing more than a fortuitously shaped stain on the rock, apparently partly algal in nature. The fossil record of whipscorpions can thus be restrained to six Pennsylvanian and one Cretaceous species.

Spiders of the family Prodidomidae are widely distributed and at least three synanthropic species have been reported. In this work we present the first record of Zimiris doriai Simon 1882 from Brazil, appartently introduced accidentally, with specimens recorded in urban areas in the states of Amazonas, Bahia, and Sergipe.

The use of carrion to feed spiderlings has never previously been observed in spiders. Here we show that the theridiid Theridion evexum Keyserling 1884 stored dead insectan prey for up to one week prior to the emergence of spiderlings from the egg sac, and continued to feed spiderlings dead prey for six weeks until spiderlings molted to the fourth instar. Spiderlings survived and molted on an experimental diet of exclusively rotten insects.

The name Araneus beebei Levi 1941 is replaced by Araneus aragua. Araneus raui Levi 1973 is replaced by Araneus missouri. The species Araneus phrygiatus (Walckenaer 1842) is not recognizable based on the original description and considered a nomen dubium.