Predation risk affects male activity and mating interactions with well-fed females in the wolf spider Pardosa milvina (Araneae: Lycosidae)

Organisms face numerous biotic and abiotic threats. Behavioural responses to these threats impact individual fitness and often affect population, community and ecosystem outcomes. Although animals face diverse threats, most studies on behavioural responses to danger have focused on responses to either predators or humans. Relatively few have tested for consistent individual differences (CIDs) in response to other common threats (e.g. pathogens, chemical stressors, fire). If behavioural responses to different threats are correlated (i.e. if individuals exhibit fear generalization), this could connect disparate sources of mortality otherwise treated as separate. Despite its potential significance, no studies to date have examined fear generalization in ecological contexts. Here, we assayed behavioural responses of wolf spiders (Schizocosa maxima) to cues associated with predation, fire and pesticide. We provide the first study to quantify CIDs in response to smoke and one of few to document CIDs in response to pesticide. We then document among-individual correlations in behavioural responses to these threats; i.e. fear generalization. We found evidence for across-threat correlations in both the magnitude of response and the type of response (e.g. flee or freeze). These novel results have important implications for the ecological consequences of animal behaviour in the Anthropocene.

Wolf Spiders as ecological models and disturbance indicator species on sandy beaches: A case study from southeastern Brazil

Three new species of Hippasa are described from China and adjacent regions of Thailand and Vietnam: H. modog sp. nov. (♂♀, Xizang, China), H. pulmoniformis sp. nov. (♂♀, Guangxi, China, and Hải Phòng Province, Vietnam), and H. thailandica sp. nov. (♂♀, Suan Phueng, Thailand). A new genus, Pandacosa gen. nov., is established to accommodate Hippasa bifasciata Buchar, 1997 (previously known only from females in Bhutan). The male of Pandacosa bifasciata (Buchar, 1997) comb. nov. is described for the first time based on specimens from Yunnan, China. A distribution map for all treated species is provided.

Recluse spiders are arachnids of potential medical significant due to their necrotic venom. However, in areas populated by the brown recluse, Loxosceles reclusa, bites and necrosis are rare. In Florida, USA, public media reports and medical case studies have propagated three misconceptions about recluse spiders: breeding populations are widespread in Florida, USA; recluse spiders readily bite when encountered; and verified recluse spider bites inevitably produce necrotic wounds. Here, in onsite investigations of 220 Florida properties with alleged infestations of recluse spiders reported to the USDA or the Florida Brown Recluse Project, we found breeding populations of the invasive Mediterranean recluse (L. rufescens) at only 19 sites. In experimental bite assays including non-injurious pressure or pinching to jaws, legs, or abdomen, brown recluse and Mediterranean spiders exhibited negligible bite responses (median = 0%). In contrast, wolf spiders exhibited significant defensive bite responses (median = 80%). Lastly, only one verified bite was reported by an adult female, which did not result in necrosis. In conclusion, our field survey and behavioral assays challenge three long-standing myths specific to Florida. Recluse spiders are scarce. Recluse spiders are reluctant to bite. Recluse spiders are unlikely to account for most necrotic skin wounds attributed to them. In the final analysis, the risk to humans has been overstated, warranting a reevaluation of their role in suspected necrotic lesions by the medical community and the public.

Developmental plasticity enables organisms to adjust life-history strategies to environmental variability. Cohort splitting-where single cohorts divide into rapid- and slow-developing individuals resulting in facultative bivoltinism-allows us to mitigate environmental unpredictability through plastic life-history decisions. We investigated this phenomenon by documenting developmental patterns under controlled photoperiod regimes in the uniquely cohort-splitting wolf spider Pardosa agrestis and a congeneric species with typical univoltine life cycle. We hypothesized that the basis of cohort splitting is rapid growth that realizes a full growth potential, but is inhibited or uninhibited in a plastic manner. Under experimental conditions, both species possessed the capacity for rapid development but differed in regulatory mechanisms. The cohort splitter species exhibited plasticity based on photoperiod and individual condition, while the non-splitter showed a more uniform response to environmental cues, independent of body state. Sibling status minimally influenced developmental outcomes, indicating low genetic determination. Our results suggest that cohort splitting evolved through differential regulation of an ancestral uninhibited growth pattern. Cohort splitting is a bet-hedging strategy that optimizes fitness in variable environments through plastic developmental inhibition. Conversely, the unconditional inhibition of rapid growth in non-splitters probably reflects adaptation to habitats where predation pressure on late-season generations favours univoltinism.

An additional mechanism of HSD3B in regulating maternal care behavior in the wolf spiders, neuropeptides.

Abstract In species with male multiple matings, males may transfer sperm differentially according to several factors such as their reproductive status and body condition, and those of their sexual partners. Spiders provide exceptional models for studying sexual selection due to their unique reproductive system, sperm storage capabilities, and diverse mating strategies. However, the factors influencing male sperm transfer in this group remain underexplored. We examined the sperm transfer patterns in the Neotropical wolf spider Allocosa senex, males of which construct and donate burrows as reproductive and paternal investment. We investigated whether male and female traits such as age and body condition (i.e. the residuals of a linear regression between prosome width and weight), and male investment in burrow construction (burrow length) influence sperm transfer. Finally, we tested the relationship between sperm transfer, the number of ejaculations, and mating duration. Our results show that sperm transfer increased with burrow length, which serves both as an advertisement to attract mates and as paternal effort in this species, suggesting this trait probably serves as an honest signal of overall male quality. Interestingly, longer mating duration showed lower sperm transfer, indicating that mating serves multiple functions beyond sperm transfer, while the positive relation among sperm transfer and the number of ejaculations support using ejaculation count as a measure of sperm transfer in this species. These findings offer new insights into the diverse factors shaping ejaculate transfer in A. senex, contributing to the understanding of factors driving the evolution of reproductive strategies in spiders and other arthropods.

Combined effects of cadmium and antibiotics on the immune defense system of the wolf spider Pardosa pseudoannulata.

The Malagasy endemic wolf spider Hippasosa ghost (Jocque & Jocqué, 2017), previously known from a single small patch of sandy habitat adjacent to a permanent lake in the Mariarano Classified Forest in northwestern Madagascar, is recorded from two additional localities with similar habitat along the Mariarano River, 10 km and 45 km from the type locality. These finds indicate the possibility that this highly specialized species could have a larger distribution than originally thought, but also they show the importance of protecting such vulnerable habitats.

ABSTRACT The pressing demand for arthropod preservation, coupled with a decline in taxonomic expertise and available resources, calls for innovative strategies in assessing biodiversity. Metabarcoding and more recently environmental DNA (eDNA) metabarcoding have been shown to be a promising technique for identifying terrestrial arthropods. This research evaluated the efficacy of two conventional sampling approaches, adapted for metabarcoding surveys, in monitoring the diversity of spiders (Araneae) and beetles (Coleoptera) within salt marsh environments. The methods tested were suction sampling (G‐vac) and modified pitfall traps (NDC, a non‐destructive DNA collector). Through two pilot experiments in salt‐marsh environments, we found that both methods successfully identified diverse arthropod communities, though discrepancies with traditional morphological identification highlighted the strengths and limitations of molecular approaches. Suction sampling excelled in detecting taxa such as Lepidoptera and Salticidae, which are often overlooked by physical collections, whereas modified pitfall traps performed well for dung beetles but faced challenges with wolf spiders (Lycosidae). Our findings underscore the importance of tailoring eDNA protocols to specific taxonomic groups and ecosystems, particularly through strategic primer and DNA fragment selection. While traditional methods remain indispensable for comprehensive biodiversity inventories, eDNA metabarcoding offers a powerful complementary approach for detecting cryptic or undersampled taxa. This study emphasizes the need for the targeted adaptation of eDNA techniques to specific taxonomic groups and ecosystems. Primer choice and DNA fragment selection significantly influenced detection efficiency, with broader primers reducing taxonomic resolution and amplifying bias. Although traditional methods remain critical for comprehensive biodiversity inventories, bulk and eDNA metabarcoding offer a complementary tool. These findings contribute to advancing arthropod monitoring tools and aiding conservation efforts amidst declining entomological resources.

T-maze navigation by juvenile wolf spiders provides evidence for learning.

ABSTRACTAssessing how elements are transferred through ecosystems provides key insights into nutrient cycling, food web interactions, and ecosystem functioning. However, studies investigating the effects of intraspecific variation on organismal elemental composition remain limited, especially for trace elements. This study investigated sex‐based differences in the elemental content of whole body and excreta of Hogna carolinensis (Carolina wolf spiders). We hypothesized that males and females would differ in whole‐body and excreta elemental composition due to divergent life history strategies. Our findings partially supported our hypothesis. Male spiders had significantly higher whole‐body concentrations of Fe, Ni, and S, whereas females had significantly more Sr. In excreta, males excreted significantly greater concentrations of Ca, Mn, Si, and Zn, while females excreted significantly higher concentrations of K and P. Principal component analysis revealed distinct elemental profiles between excreta and whole‐body samples, with both sexes exhibiting higher concentrations of Ba, Ca, Fe, K, N, Na, P, S, and Si in excreta, and lower concentrations of Cu, Li, and Ni than in their whole body. These results suggest that sex‐specific excretion patterns may influence micronutrient cycling and ecosystem function, particularly regarding the deposition of nutrients such as Ca, K, Mn, P, Si, and Zn. Given the potential ecological implications of sex‐based nutrient fluxes, future research should further examine how intraspecific variation and sexual dimorphism shape stoichiometric phenotypes and trophic interactions.

Repellent effect of selected essential oils against the wolf spider Pardosa hortensis (Araneae: Lycosidae).

Selecting high-quality commercial ingredients is crucial for success in arthropod mass-rearing and laboratory research, yet chemical labels often provide incomplete information for predicting in vivo performance. A gap exists for rapid, cost-effective functional assessment tools. This study proposes and validates a pragmatic bio-assay framework to address this need, using two commercial brown sugars (a common dietary supplement) with different labeled protein contents [high-protein brown sugar (HPBS), 28 g kg-1; low-protein brown sugar (LPBS), 7 g kg-1) as a case study. In starvation survival assays, wolf spider (Pardosa pseudoannulata) juveniles provided with the HPBS solution showed significantly prolonged survival compared to those on the LPBS solution. In life-cycle assays with fruit flies (Drosophila melanogaster), flies reared on a HPBS-supplemented diet exhibited significantly higher cumulative fecundity and superior climbing ability compared to those on the LPBS diet. By contrast, no significant difference in total developmental time was observed among the dietary treatments. The proposed bio-assay framework successfully distinguished the functional quality of the two commercial ingredients based on key performance metrics. The consistent superiority of the HPBS product, despite the 'black box' nature of commercial products (i.e. potential confounding factors), validates this approach as a powerful tool. It provides practitioners in applied arthropod nutrition with a rapid, accessible, and functionally relevant method for ingredient quality control, complementing or even preceding more complex chemical analyses. © 2025 Society of Chemical Industry.

Plant-derived pesticides (PDPs) are increasingly promoted as 'eco-friendly' alternatives to agrochemicals because of their low vertebrate toxicity, yet their safety for non-target arthropod natural enemies is rarely tested, especially the enrichment effect via trophic transfer. We cultured fruit flies using media supplemented with two widely applied Chinese PDPs in tea plantations, matrine or azadirachtin, under commercial concentration, which were fed to newly emerged spiderlings of wolf spider Pardosa laura (Araneae: Lycosidae) throughout their entire life cycle. We examined the effect of these two PDPs on their survival, developmental parameters and reproduction. The results showed that developmental traits remained unaffected, but both PDPs markedly suppressed male mating success and female fecundity. Histological examination of paraffin sections revealed markedly impaired ovarian maturation. Microbiome profiling indicated that pesticide exposure disrupted ovarian microbial communities, with azadirachtin exerting the strongest effect, whereas gut and testicular communities remained largely unchanged. Transcriptomic analysis of ovaries showed significant enrichment of pathways related to ovarian development. Ten representative differentially expressed genes (DEGs) within these pathways were selected and validated by RT-qPCR. PDPs may not compromise the development of spiders in the first generation, yet they can severely affect reproduction of the spiders, thereby precipitating substantial declines in population size of future generations. This result challenges the conventional wisdom of botanical pesticides, inspiring re-consideration of their rational use in integrated pest management. © 2025 Society of Chemical Industry.

ABSTRACTEgg-sac brooding is a costly maternal strategy for which evolutionary persistence hinges on clear offspring benefits and effective maternal tactics to offset those costs. Using the wolf spider Pardosa pusiola, we examined (1) whether hatchling emergence depends on the presence of a conspecific mother, (2) whether egg sac opening is a flexible response to embryonic cues, and (3) how mothers modulate locomotor performance under different ecological risks (sun exposure, flooding, predation). Conspecific foster mothers matched biological mothers in synchronizing egg-sac opening with embryonic development, whereas interspecific foster mothers (Pardosa astrigera) mistimed opening in most cases. Motherless egg sacs contained fully developed but un-emerged hatchlings, confirming that maternal presence is indispensable for emergence, not for hatching itself. Under moderate sun exposure, egg-sac-carrying females escaped slower than non-carrying females. Under high sun exposure or predator stimulus, carrying females escaped as fast as or faster than non-carrying females. Under simulated flooding, carrying females suffered higher mortality, yet survivors showed no difference in escape speed compared to non-carrying females. These results demonstrate flexible egg-sac management coupled with adaptive maternal locomotion, illustrating how costly parental care can be maintained when parents adjust their behavior according to environmental risk.

Arachidonic acid regulates hormonal crosstalk to promote molting success and mediate a life-history trade-off in a wolf spider.

Tissue-resident microbiomes shape stress resilience and dispersal behavior in an agrobiont spider.

ABSTRACT Female wolf spiders (Lycosidae) are characterized by their multifaceted offspring care, including carrying the egg sac attached to their spinnerets. The factors determining this care may be related to both the physiology of the female and chemical signals from the egg sac. In this study, we analysed behavioural and chemical aspects of maternal care in Pardosa paludicola. The behaviour of females who carried egg sacs was analysed for the time spent on different activities, and their frequency. Chemical compounds from egg sacs at various ages were identified by gas chromatography–mass spectrometry. It has been shown that the more time that has passed after the egg sac was made, the less time the female spends resting, and the more time it spends moving. Egg sac manipulation is a significant activity on the first day after making the egg sac, and females carrying egg sacs containing already moving juveniles show more dynamic and variable activity. The chemical profile of the egg sac contains more than 140 chemical compounds, i.e. alcohols, hydrocarbons, fatty acids, and esters, the content of which changes with the days of care. The greatest changes in the content of many of these compounds occur on day 20, associated with the development of mobile juveniles in the egg sac. Among the identified compounds, fatty acids and sterols have a broad spectrum of antibacterial and antifungal properties.