We examined the role of lycosid eye rows and the pairs of eyes within each row in prey detection and mate recognition by Schizocosa ocreata (Hentz, 1844) using two approaches: (1) occluding anterior or posterior eye rows; and (2) occluding all but a single eye pair. In response to live prey, females took longer to orient and approach crickets when the posterior eye row was occluded; responses were intermediate when the anterior eye row was occluded. With six of eight eyes occluded, spiders that could see with posterior lateral eyes (PLE-only) detected the cricket as quickly as the fully sighted spiders (controls), while spiders limited to seeing from other eye pairs took longer to orient towards prey. Orientation distance varied significantly as well, with Control, ALE-only, PME-only and PLE-only spiders responding at greater distances than AME-only spiders. To analyze the functions of the eye rows involved in mate preference in S. ocreata, we conducted an additional study with presentation of video playback of a courting male to females with different eye rows occluded. Females with their posterior eyes occluded took longer to orient and respond compared to controls and anterior eye row occlusion. The sum of female receptivity displays was also significantly reduced when posterior eyes were occluded, suggesting the posterior eyes may be involved in mate recognition. Taken together, these data suggest that the posterior (secondary) eyes may have an important role in detection and identification of both prey and courting males.

Antibiotic resistance is a global health crisis. Our current arsenal of antibiotics—drugs meant to kill bacteria and stop their population growth—is becoming less effective at treating bacterial infections as resistant bacteria emerge, fueling the dire need to discover new antibiotics. Most antibiotics in use today have been discovered from bacteria. To increase the chances of finding potentially novel antibiotic molecules, we studied the relatively unexplored microbial environment of scorpion tissues, using the giant sand scorpion, Smeringurus mesaensis (Stahnke, 1957). Bacterial symbionts were isolated and cultured from the mesosoma and metasoma, and isolates were tested in a functional assay for production of antibiotics. Under the culture conditions utilized, most scorpion-derived bacteria were from the phyla of Firmicutes, Proteobacteria and Actinobacteria. Fifty-five percent of the clonal isolates tested produced antibiotics, with most being Bacillus species. None of the bacterial conditioned media were cytotoxic to mammalian cells. This study suggests scorpion tissues may provide a rich source of antimicrobial molecules to help combat the antibiotic resistance crisis.

Cold temperatures can cause injury and death, and thermal tolerance influences organismal abundance, distribution, and physiology. We characterized cold tolerance and supercooling point (SCP) in the broadly distributed jumping spider Phidippus audax (Hentz, 1845). We found that P. audax is freeze-avoidant, surviving chilling but not freezing. Freeze-avoidant organisms can reduce harm by lowering their supercooling point (SCP), the temperature at which they freeze. We assayed fall/winter SCP in field-acclimated spiders from Michigan and compared lab-acclimated spiders from Texas, Oklahoma, and Michigan. Field-acclimated Michigan spiders decreased their SCP from –4.7 °C in September to –12.9 °C in November. In the lab, Michigan spiders had the lowest SCP (–7.65 °C) followed by Oklahoma (–6.21 °C) and Texas (–5.50 °C). In December and January, nearly all the spiders from Texas and Oklahoma died in the simulated freezing conditions while the Michigan spiders survived at high rates, further suggesting that the Michigan spiders were hardiest followed by Oklahoma and Texas. The lab-acclimated spiders did not consistently reduce their SCP from October to December. Smaller spiders had lower SCPs than larger spiders, and the Michigan spiders were significantly smaller than those from Texas or Oklahoma, suggesting that smaller overwintering size or delayed molting to mature size/sexual maturity may be favored by selection in colder climates. This could help explain differences in size and life cycle between northern and southern P. audax, as well as a previously described trend for smaller spiders to be more common in colder areas or Europe.

Harvester species exhibit a diverse array of defenses against predators. In this article, we briefly cover chemical defenses, coloration patterns, autotomy, aggregations, freezing behavior, bobbing, body vibration, and the production of sounds that might be used to avoid predators' attacks. Those defenses are not present in all harvester species and may not deter all kinds of predators. We discuss how prey-predator interaction may shape the evolution of defenses. Here we focus on studies that have been done after 2007, and we aim to give a general idea of the knowledge about prey-predator interactions in Opiliones to date, especially to the general public.

In this paper the findings of a global literature and social media survey of spider mycoses are presented. Our survey revealed that spider mycoses occur in the geographic belt between latitude 78°N and 52°S, and that more than 40 out of the known 135 spider families (ca. 30%) are attacked by fungal pathogens. Jumping spiders (Salticidae), cellar spiders (Pholcidae), and sheet-web spiders (Linyphiidae) are the families most frequently reported to be attacked by fungal pathogens (combined >40% of all reported cases). Ninety-two percent of the infections of spiders can be attributed to pathogens in the order Hypocreales (phylum Ascomycota), and almost exclusively the families Cordycipitaceae and Ophiocordycipitaceae. Within the Hypocreales, the asexually reproductive genus Gibellula is an historically species-rich and widespread genus of specific spider-pathogenic fungi. For ca. 70 species of spider-pathogenic fungi their hosts could be identified at least to family level. The data presented here reaffirm the findings of previous studies that spider-pathogenic fungi are most common and widespread in tropical and subtropical forested areas, with free-living cursorial hunters – dominated by Salticidae – being the most frequently infected. Cursorial hunters (especially Salticidae) and subterranean cellar spiders (Pholcidae) are the most frequently fungus-infected spiders in North America, whereas web-weavers (especially Linyphiidae and Pholcidae) are the most common spider hosts in Europe. Our survey implies that spider-pathogenic fungi are an important mortality factor for spiders which has hitherto been underestimated.

Ants are among the most ecologically dominant animals in several terrestrial ecosystems. Some myrmecophile species use ants to transport themselves, a behavior known as phoresy or phoresis. Although phoresis is commonly reported in arachnids such as pseudoscorpions or acari, it is very unusual among spiders. Phoresis on ants has only been reported in one genus of spiders, the sac-spider Attacobius Mello-Leitão, 1925 and for only two Brazilian species. In this report, we describe this amazing behavior in Attacobius nigripes (Mello-Leitão, 1942) for the first time in association with a new host, the leaf-cutting ant Acromyrmex lobicornis Emery, 1888. This record extends the geographic distribution of this spider species to the southwest of Argentina, from the Chaco into the Monte Desert region. We briefly describe the riding behavior of spiders and discuss the myrmecophile association between this species and A. lobicornis. More studies are needed to understand the evolutionary context of this association.