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We developed a monoclonal antibody (MAb) to Platynota stultana (Tortricidae, common name omnivorous leafroller), a key pest of grape in California, and used it to detect predation by spiders in San Joaquin Valley vineyards. Using an enzyme-lined immunosorbant assay, we found a MAb with high specificity to P. stultana, with no cross reaction to several non-lepidopteran insects, and minor reaction to other lepidopteran species. We tested the MAb on four spiders: Cheiracanthium inclusum (Hentz, 1847) (Cheiracanthiidae), Trachelas pacificus Chamberlin & Ivie, 1935 (Trachelidae), Oxyopes spp. (Oxyopidae) and Hololena nedra Chamberlin & Ivie, 1942 (Agelenidae), and found for all but C. inclusum, there was reactivity to spiders which had eaten P. stultana larvae in the laboratory. We sampled spiders from two Fresno County vineyards, assaying by species and weight at antigen dilutions of 1:100 and 1:1000. None of the small-sized Oxyopes spp. or H. nedra specimens was positive, but 8.8% of the medium-sized Oxyopes spp. and 33.3% of the medium- and large-sized H. nedra specimens were. 28.5% of the small-, 57.1% of the medium- and 66.6% of the large-sized T. pacificus specimens tested positive. Our interpretation is that the H. nedra positives resulted from P. stultana moth capture, and that Oxyopes spp. prey upon P. stultana larvae, but have a limited ability to capture them. Trachelas pacificus appears to be an effective predator of immature P. stultana, capable of finding and consuming those hidden in their nests, and may play a positive role in lowering its population density.

A new troglobitic species belonging to the genus Paratricommatus Piza, 1943 (Cryptogeobiidae), was found in a cave in the Pains municipality, Minas Gerais state, Brazil, and is described here. Paratricommatus infernalis sp. nov. is distinguished from all other species in the genus by having the IV femur 1.5–2.5 longer than the dorsal shield (instead of the IV femur shorter than the dorsal shield) and small eyes with reduced pigmentation. This new species presents several troglomorphic traits, such as elongated legs and different degrees of reduction in integumentary and ocular pigmentation, in addition to being absent in epigean environments. Thus, it is considered a troglobitic species and may represent a relic, as evidenced by its geographic isolation from other Cryptogeobiidae species.

In the present study, the reproductive behavior of a representative of the Deinopidae family, Deinopis cf. cylindracea C. L. Koch, 1846, is described for the first time. The behavioral aspects observed were the construction of the male's sperm web, male's approach to fertilization, and end of the couple's pairing. As soon as a male found a female, he began sperm induction. The sperm web is a Y-shaped web, whose internal space forms a flat surface onto which the male deposits his gametes. Sperm were then collected by his copulatory bulbs from the opposite side of the web. After transferring the sperm drops to the pedipalp, the male walked towards the female, approaching her from the dorsal-abdominal region using the dragline thread of the web. The male used his legs to touch both the web and female spider, inducing the female to let go, and positioned her ventral region towards his cephalothorax. The couple hung upside down; the female was suspended by a thread, her cephalothorax perpendicular to the floor. In this position, the male inserted the embolus of the copulatory bulb into the female epigynum and transferred the sperm. The male separated quickly by extending his legs and moving away, returning to an uppermost position in relation to the female. The female, in turn, returned to the prey-ready posture, clipping the capture net again and positioning herself in the same manner as before the reproductive behavior.

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.

Systemic optimization of RNA extraction protocols in non-model arachnids is indispensable for gene expression studies, including transcriptome sequencing and analyses. Spinnerets of the Neotropical tarantula Grammostola actaeon (Pocock, 1903) (family Theraphosidae) were used to evaluate the performance of two RNA extraction reagents and three commercially available kits for isolating total RNA from small eukaryotic tissue samples. Total RNA was extracted from spinneret tissues, using two samples for each method. We used the commercially available reagents TRIzol and NucleoZOL and the RNA extraction kits NucleoSpin and NucleoSpin XS (Macherey Nagel) and Total RNA Purification Kit (Norgen Biotek Corp). Quantification using Qubit revealed that NucleoSpin, Norgen, and NucleoSpin XS resulted in the highest RNA yields respectively, while Nanodrop analysis ranked Norgen, TRIzol, NucleoSpin, NucleoSpin XS in descending order. Bioanalyzer analysis indicated that Nucleospin, and NucleoSpin XS delivered the best results for our samples. While each method successfully yielded sufficient RNA for RNA-seq experiments, variations in RNA quality among methods indicate differences in their suitability for specific applications. Our data provide further evidence that RNA integrity number (RIN)-based assessments in G. actaeon may not be reliable for evaluating RNA quality due to a widespread occurrence of the ‘gap deletion’ phenomenon in arthropods. RNA from species with 28S rRNA collapsed can yield high-quality transcriptomes, suggesting that current RIN-based assessments may not be reliable for evaluating RNA quality in many non-model invertebrates. Overall, differences in results of commercially available RNA extraction reagents/kits should be considered when selecting the most appropriate RNA extraction method for gene expression analysis.

Spiders possess multiple types of silk glands, producing silk materials with contrasting properties, which are deployed in distinct behavioral contexts, such as locomotion, prey capture and egg casing. Whereas the diversity of silk glands and spigots across different spider families is relatively well described, their biological functions (i.e., with which behavior each gland type is activated) are poorly known. Here we provide an overview about available methods and approaches to determine the biological function of spider silk glands, and evaluate their advantages and disadvantages based on our experiences and a test study on Pholcus phalangioides (Fuesslin, 1775) (Pholcidae) and Kukulcania hibernalis (Hentz, 1842) (Filistatidae).

Orb web weaving spiders, like Argiope trifasciata (Forsskål, 1775), rely on sticky aggregate glue droplets on the capture spiral of their web to retain prey. Here, we compared the protein composition of the glue droplets placed at the bottom of the web early in capture spiral construction, to those placed at the inside of the web late in web construction. We found a lower abundance of aggregate proteins in the inner web, where the droplets are smaller, are less extensible, and contain a higher proportion of water. Interestingly, we also found that pyriform spidroin, which anchors bridging lines of the web to the substrate, was more abundant in the inner region of the web, which has a higher density of capture spiral-radial line junctions. We propose that pyriform spidroin has a previously unidentified role in orb webs: anchoring the capture spiral to radial lines.

Among the variety of wolf spiders in Europe, there are some uncommon and poorly known species. An example is Pardosa paludicola (Clerck, 1757), which is classified as endangered and rare in some countries. We used a capture-mark-recapture method to examine the biology of mature P. paludicola individuals, focusing on the movement ranges of this spider. We marked 714 individuals and more than 10% of them were recaptured (♂ 4.5% and ♀ 14.7%). The median movement range was calculated at 5–6 m for both sexes and the maximum distances reached 58–69 m in 3–4 days. In the context of conservation efforts for this species, it seems important to provide large open areas of high humidity, with low human interference.

In this study, we provide an update on the knowledge of vertebrate-eating jumping spiders. Twenty-four reports of jumping spider predation on vertebrates are known, which are attributed to seven species: Hyllus diardi (Walckenaer, 1837), H. semicupreus (Simon, 1885), H. treleaveni GW Peckham & EG Peckham, 1902, Paraphidippus cf. aurantius, Phidippus bidentatus FO Pickard-Cambridge, 1901, P. regius CL Koch, 1846, and an unknown species apparently related to Hasarius Simon, 1871. In addition, several unsuccessful predation attempts by Phidippus audax (Hentz, 1845) on hummingbird and chickadee nestlings are documented. Furthermore, an incident of Phidippus otiosus (Hentz, 1846) feeding on an oversized gecko carcass (likely a case of scavenging) is reported. Overall, incidents of vertebrate predation by salticids are likely to be, in most cases, very rare chance encounters between a tiny vertebrate and a hungry spider. In contrast, the case of Phidippus regius is unique for salticids as—to the current state of knowledge—this is the only salticid species in which vertebrate consumption has been reported numerous times (n = 18) and in many different locations (11 different Florida counties, USA).