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The ideal free distribution (IFD) theory predicts that individuals are free to move among habitat patches and distribute among them “ideally,” in order to maximize individual evolutionary fitness. Size and quality of habitat patches then should directly impact the number of individuals occupying them, and connectivity of habitat patches likely plays a role if dispersal is limited. However, habitat patches can be distributed so that movement no longer can be considered free, for example, when patches are isolated. Challenges stemming from patch delimitation and detection rate of occupants further complicate efforts attempting to resolve such patterns. Here, we utilize as habitat patches the orb webs of four different populations belonging to three golden orb weaver spider species, Nephila pilipes (Fabricius, 1793), Nephilingis livida (Vinson, 1863), and Trichonephila clavipes (Linnaeus, 1767), and the obligate spider kleptoparasites (Argyrodinae, Theridiidae) that are associated with their webs. We examine how the IFD predicts the abundance of kleptoparasites under different patterns of patch size and distribution. We found that larger host webs, that is, habitat patches that contain more resources, are occupied by a higher number of kleptoparasitic spiders, regardless of their degree of isolation. Although the free movement prediction is often violated in natural systems, we find no evidence for habitat patch connectivity affecting the abundance of kleptoparasites, indicating that their dispersal ability facilitates the location and colonization of habitat patches regardless of their isolation. Therefore, our results support the interaction between argyrodine kleptoparasitic spiders and the webs of golden orb weavers to be a suitable natural system for studying the IFD. [ABSTRACT FROM AUTHOR]

All animal species, from arthropods to vertebrates, must deal with occasional stressors in their lives, though most research on this has been focused on vertebrates. Meanwhile, our understanding of stress reactions in arthropod species like spiders is nascent. In the United States, a non‐native orb‐weaving spider, Trichonephila clavata (‘jorō’ spider), is spreading as is its already‐established cousin in the United States, T. clavipes (golden silk spider). Prior study has revealed how these two species have a unique behavioural reaction to physical stressors, whereby they remain in a thanatosis state for a prolonged period compared with other species. Here, we investigate the physiological stress reactions of these Trichonephila spiders by evaluating how each species' dorsal vessel contractions (heart rates) become elevated after being subjected to a non‐lethal stressor. For comparison, we also evaluate two similarly‐sized orb weavers, Argiope aurantia (garden spider) and A. trifasciata (banded garden spider). We record baseline heart rates of inactive, resting, spiders in our lab, then restrain them under an electronic, ‘optocardiographic’, sensor for 10 min, to record their ‘stressed’ heart rates. Argiope aurantia has a pronounced heart rate elevation, for reasons unknown. We observe that all spider heart rates increase during restraint, though each has a species‐specific pattern of elevation over time under restraint. Notably, heart rates of both Trichonephila spiders are less variable under stress, since they tend not to struggle during restraint. Meanwhile, both Argiope spiders frequently struggle, leading to marked fluctuations in cardiac output. The stress reactions of Trichonephila spiders could be characterized as ‘even‐tempered’, which may factor into their ability to live in habitats with frequent disturbances. [ABSTRACT FROM AUTHOR]

Simple Summary: Spiders are considered natural polyphagous bio-control agents of agro-ecosystems and the best indicators of environmental health. They have the ability to adapt to different environments and are, therefore, present in almost all types of terrestrial ecosystems. The behavior of spiders is influenced by different biotic and abiotic factors, such as roadside disturbance, which may affect normal web-building behavior. Spiders, Neoscona vigilans, were captured, body measurements were taken, and their web characteristics along the road premises were calculated. Web characteristics had a significant association with spider body characteristics and also with the distance from the road, which changed gradually as the webs were constructed closer to the road. Road disturbance had a negative impact on normal web construction as more defects were observed in the webs constructed closer to the road, while dramatically more perfect webs were observed as the distance from the road increased. We concluded that disturbances such as roadside traffic had diverse effects on spider behavior. The outcomes of this study provide insight into the role of traffic on the livelihood of spiders encountering human-influenced disturbance in the ecosystem. Orb web spiders are common and highly diversified animals found in almost all habitats. They have remarkable plasticity against biotic and abiotic factors, making them excellent indicators of environmental health. The web creation behavior of spiders is influenced by disturbances in the environment. The aim of this research was to observe the alteration in the web-building behavior of Neoscona vigilans caused by human activities, specifically traffic disturbances. Spider webs were located and photographed at nighttime along the roadside, and their web characteristics were calculated. Spiders were captured from webs for their body measurements. Spider fourth leg length, carapace width, and body length had a significant association with web size and diameter, CTL, capture area, and mesh size. The quantity of trapped prey, the height of the plant, and the foliage radius increased with the distance from the road. Conversely, anchor points and web elevation from the ground dropped. The highest and lowest proportions of anomalies (modifications/defects) were recorded as holes (52.7%) in 105 webs (100%) and supernumerary (0.7%) in 55 webs (52.4%), respectively. Road disturbance had a negative influence on the spider's behavior as the webs formed in close proximity to the road had a higher frequency of anomalies, with a gradual decrease distantly. We can gain further insight into how different environmental changes, disruptions, and pollutants lead to this imperfection in the otherwise flawless perfect structure of spider webs. [ABSTRACT FROM AUTHOR]

Temporal change in vegetation complexity and field management may interactively affect the structure of predator–prey networks in agroecosystems and consequently alter the biocontrol potential of predators. There is a limited number of studies that have addressed these questions for generalist predator–prey networks.We investigated how vegetation complexity during crop development and management type (conventional vs. organic) affect the trophic networks of orb‐weaving spiders and their prey in rainfed lowland rice ecosystems in southern Thailand. Specifically, we investigated orb‐weaving spiders and prey composition, prey selectivity and network structure.Overall, orb‐weaving spiders captured mostly detritus‐associated Diptera, aquatic‐associated Ephemeroptera and Hemiptera pests. The increasing vegetation complexity during rice development significantly restructured the network of orb‐weaving spiders and prey, while field management had only a marginal effect. The increased vegetation complexity during rice development led to an increased number of weak trophic interactions in comparison to few but strong interactions in simple vegetation.Our results indicate that increasing the number of spider species per prey taxon (prey vulnerability) in late rice season may enhance their top‐down control of prey including rice pests. This study also highlights that the network complexity and the stability of rice ecosystems increased during the rice growing season as the vegetation became more complex.Future practices could look for a way to support the densities of detritus and aquatic insects and to artificially increase habitat complexity during the early stage of rice development to improve the biocontrol services provided by the orb‐weaving spiders. [ABSTRACT FROM AUTHOR]

Intraguild predation occurs when an organism preys on a competitor. This ecological interaction can have considerable consequences on the population dynamics of predators and indirectly affect their prey. In arachnids, it is a quite common phenomenon, but it has been poorly documented in the Neotropical region. Here, we present records of 16 species feeding on other 14 species of arachnids. The most common families that acted as predators were Buthidae (Scorpiones) and Salticidae (Araneae), while the most common prey were members of the families Araneidae and Ctenidae (Araneae). In our survey, Drake Bay, in Costa Rica, is overrepresented due to years of systematic observations by two of the coauthors. [ABSTRACT FROM AUTHOR]

In this paper, we provide additional data on the orb-weaver spider fauna (Araneae: Araneidae) of Kosovo. Three species are reported for the first time from this country: Araneus grossus (C.L. Koch, 1844), Argiope lobata (Pallas, 1772) and Cyclosa oculata (Walckenaer, 1802). In consideration of the findings and the updated checklist of Araneidae in this study, the documented number of spider species in Kosovo has now increased to 251. Given that the spider fauna of Kosovo is still not fully explored, our study emphasizes the necessity of ongoing exploration to better comprehend the diversity of spider species within the region. [ABSTRACT FROM AUTHOR]

Many orb-web weaving spiders add highly visible zigzagging silk "decorations" to their webs that are thought to function in prey attraction or predator avoidance. Despite the long history of studies on the form, frequency, and function of these structures, little attention has been paid to their mode of construction. Here, we report for the first time the sequence of construction of decorations by Argiope luzona (Walckenaer, 1841), a common species in the northern Philippines. A disc-shaped decoration built by a juvenile was laid as several continuous loops in a modified figure-eight pattern. The resulting asymmetric design is typical of many Argiope spp., hence suggesting that disc decorations are built similarly across the genus. In a full cruciate decoration of an adult female spider -- consisting of four diagonal arms arrayed around the web's hub -- each two-armed diagonal was laid down in turn, each arm being laid from its outermost portion inward, the lower arm first. The mode of construction of the cruciate device suggests that this type of decoration evolved by duplication and diagonalizing the single two-armed vertical decoration seen in presumptively less derived Argiope. [ABSTRACT FROM AUTHOR]

Orb-weaver spiders produce upwards of seven different types of silk, each with unique material properties. We focus on the adhesive within orb-weaving spider webs, aggregate glue silk. These droplets are composed of three main components: water, glycoproteins, and a wide range of low molecular mass compounds (LMMCs). These LMMCs are known to play a crucial role in maintaining the material properties of the glycoproteins, aid in water absorption from the environment, and increase surface adhesion. Orb-weavers within the Cyrtarachninae subfamily are moth specialists and have evolved glue droplets with novel material properties. This study investigated the biochemical composition and diversity of the LMMCs present in the aggregate glue of eight moth-specialist species and compared them with five generalist orb-weavers using nuclear magnetic resonance (NMR) spectroscopy. We hypothesized that the novel drying ability of moth-specialist glue was accompanied by novel LMMCs and lower overall percentages by silk weight of LMMCs. We measured no difference in LMMC weight by the type of prey specialization, but observed novel compositions in the glue of all eight moth-catching species. Further, we quantified the presence of a previously reported but unidentified compound that appears in the glue of all moth specialists. These silks can provide insight into the functions of bioadhesives and inform our own synthetic adhesives. [ABSTRACT FROM AUTHOR]

Female sperm storage organs in arthropods are used as taxonomic characters since it is assumed that they do not change after maturation. However, in the Golden Silk spider, Trichonephila clavipes, the shape and sclerotization of the spermathecae change with a mating event. Moreover, mating in T. clavipes consists of several hundred copulations, but the male transfers all sperm during the first insertion of each pedipalp. Given this puzzling mating behaviour, we hypothesize that multiple copulations serve purposes other than sperm transfer and uptake, such as further altering the morphology of the storage site and/or transferring substances other than sperm. We compared virgin female T. clavipes with females after two copulations, one for each spermatheca, and after ad‐libitum mating. Each treatment consisted of two sub‐treatments in which the state of the sperm storage organs was inspected after a short (1–3 days) or a long (11 days) time interval after the female's final moult. The size of the spermathecae increased twofold in all mating treatments compared to virgin females. The thickness of the spermathecal wall increased significantly with time in all treatments similarly. The spermathecal epithelium, which releases secretion into the lumen of the spermathecae, seems most active in virgin females during the time when mating would normally occur and turns less active after mating and with age. The spermathecae contain secretion produced by the female before mating; and after mating, sperm and another secretion transferred by the male. The numerous sperm‐less matings in the ad‐libitum treatment resulted in male secretion in the copulatory ducts of the female genitalia, likely impeding sperm transfer by subsequent males. Out study shows that female genitalia can change considerably after having reached maturity and suggests that sperm‐less matings evolved in the context of sperm competition. [ABSTRACT FROM AUTHOR]

Although spiders are one of the most diverse groups of arthropods, the genetic architecture of their evolutionary adaptations is largely unknown. Specifically, ancient genome-wide duplication occurring during arachnid evolution ~450 mya resulted in a vast assembly of gene families, yet the extent to which selection has shaped this variation is understudied. To aid in comparative genome sequence analyses, we provide a chromosome-level genome of the Western black widow spider (Latrodectus hesperus)—a focus due to its silk properties, venom applications, and as a model for urban adaptation. We used long-read and Hi-C sequencing data, combined with transcriptomes, to assemble 14 chromosomes in a 1.46 Gb genome, with 38,393 genes annotated, and a BUSCO score of 95.3%. Our analyses identified high repetitive gene content and heterozygosity, consistent with other spider genomes, which has led to challenges in genome characterization. Our comparative evolutionary analyses of eight genomes available for species within the Araneoidea group (orb weavers and their descendants) identified 1,827 single-copy orthologs. Of these, 155 exhibit significant positive selection primarily associated with developmental genes, and with traits linked to sensory perception. These results support the hypothesis that several traits unique to spiders emerged from the adaptive evolution of ohnologs—or retained ancestrally duplicated genes—from ancient genome-wide duplication. These comparative spider genome analyses can serve as a model to understand how positive selection continually shapes ancestral duplications in generating novel traits today within and between diverse taxonomic groups. [ABSTRACT FROM AUTHOR]

Simple Summary: Orb-weaving spiders can learn to avoid eating unpalatable prey, but what happens when they encounter one that they have never seen before? In the United States, a spider from East Asia has become established (the "jorō spider") in recent years, and their webs are most prominent during the late-summer and fall, which is also when migrating monarch butterflies are in abundance. Since monarch butterflies are unpalatable (because of developing on toxic milkweeds), we wondered if jorō spiders would recognize this and avoid eating them, given that these species do not coexist in East Asia. Using field observations of butterflies deposited into jorō spider webs, we found that these spiders do avoid eating monarchs, and even remove them from their webs in some cases. They readily attack other butterflies, even those that are similarly colored to monarchs. This raises many questions about how they perceive the "distastefulness" of monarchs, even without tasting the butterflies first. An invasive spider from East Asia has established in the U.S. southeast (the "jorō spider," Trichonephila clavata) and is rapidly expanding its range. Studies assessing the impact of this species are needed, including how expansive its diet is. An open question is whether monarch butterflies, Danaus plexippus, are a potential prey item for this spider, given that jorō spiders do not coexist with monarchs in their native range. Since monarch larvae feed on milkweed, they sequester cardiac glycosides into their adult tissues, rendering them unpalatable to many predators. At sites within northeast Georgia, we staged a series of trials (n = 61) where we tossed monarchs into jorō spider webs and, for comparison, performed similar trials with another aposematic species, gulf fritillary (Agraulis vanilla), and a palatable species, tiger swallowtail (Papilio glaucus). We recorded the outcome of the trials, which included whether the spider attacked or did not attack the prey. We also conducted a visual survey during the same fall season to look for evidence of jorō spiders consuming monarchs naturally. Our findings revealed that jorō spiders avoided eating monarchs; spiders only attacked monarchs 20% of the time, which was significantly less than the attack rates of similarly sized or larger butterflies: 86% for gulf fritillaries and 58% for tiger swallowtails. Some jorō spiders even removed monarchs from their webs. From our visual surveys of the surrounding area, we found no evidence of natural monarch consumption and, in general, butterflies made up only a fraction of the jorō spider diet. We conclude that jorō spiders appear to recognize monarch butterflies as being unpalatable, even without having a prior history with the species. This invokes questions about how these spiders can immediately recognize their unpalatability without touching the butterflies. [ABSTRACT FROM AUTHOR]

Worldwide, with the decline of natural habitats, species with reduced niche breadth (specialists) are at greater risk of extinction as they cannot colonise or persist in disturbed habitat types. However, the role of thermal tolerance as a critical trait in understanding changes in species diversity in disturbed habitats, e.g., due to forest replacement by tree plantations, is still understudied. To examine the role of thermal tolerance on the responses of specialist and generalist species to habitat disturbances, we measured and compared local temperature throughout the year and thermotolerance traits [upper (CTmax) and lower (CTmin) thermal limits] of the most abundant species of spiders from different guilds inhabiting pine tree plantations and native Atlantic Forests in South America. Following the thermal adaptation hypothesis, we predicted that generalist species would show a wider thermal tolerance range (i.e., lower CTmin and higher CTmax) than forest specialist species. As expected, generalist species showed significantly higher CTmax and lower CTmin values than specialist species with wider thermal tolerance ranges than forest specialist species. These differences are more marked in orb weavers than in aerial hunter spiders. Our study supports the specialisation disturbance and thermal hypotheses. It highlights that habitat-specialist species are more vulnerable to environmental changes associated with vegetation structure and microclimatic conditions. Moreover, thermal tolerance is a key response trait to explain the Atlantic Forest spider's ability (or inability) to colonise and persist in human-productive land uses. [ABSTRACT FROM AUTHOR]

Argiope anasuja Thorell, 1887 is a species of orb-weaving spider found in tropical and subtropical regions of the world. Despite its widespread distribution, little is known about its natural history and mating behavior. In this study, I describe some aspects of the natural history and mating behaviors of A. anasuja in captivity and in natural habitats. The spiders were found to occupy less shady areas close to water bodies, building their webs between 50 to 200 cm above the ground level. Web decorations were common in female webs, primarily in the central area, and consisted of dense zigzag bands of silk. A significant difference in copulation duration was observed between cannibalized and non-cannibalized individuals. Furthermore, a significant difference in copulation duration was found between individuals in natural environments and laboratory conditions. However, no significant difference was observed in courtship duration between individuals in natural environment and laboratory conditions. Understanding the mating behaviors of A. anasuja is important because they play a key role in determining the success of mating. This study highlights the natural history and mating behavior of A. anasuja, contributing to our understanding of this species in Sri Lanka. [ABSTRACT FROM AUTHOR]

Globally, arthropod populations are declining at alarming rates, but the causes are rarely understood. Our research details and examines possible causes for fluctuations in the size of a Costa Rican population of golden silk orbweaver spiders (Trichonephila clavipes (Linnaeus, 1767)). Over a seven-year period from 2013–2019, we noted a sharp decline and then partial recovery of the study population during the wet season (June, July), but then failed to locate any spiders during a brief survey in June 2022 when they would otherwise be abundant. We monitored webs daily during 2013–2019 to test whether variation in prey capture, competitors, female size, male availability, predation, temperature, or rainfall related to population fluctuations. We were unable to explain T. clavipes population trends with the collected data. Future studies are needed to determine whether the extremely low population densities we witnessed in 2017 and 2022 can be interpreted as the lowest values of this species' normal population fluctuation cycle or whether these extremes are part of a long-term spider decline. [ABSTRACT FROM AUTHOR]

The present work deals with the diversity of spiders during the monsoon within the Saurashtra University Campus, Rajkot, Gujarat. A total of 38 species of spiders belonging to 32 genera and 14 families were recorded. Araneidae (25.81%) was found to be the most dominant family, with nine species from five genera. Guild structure analysis revealed seven feeding guilds, among all 31% most dominant feeding guilds represented by orb-web builders and stalkers, followed by ground runners (13%), irregular webs (10%), ambushers (7%), foliage hunters (6%), and space-web builders (2%). Ecological indices reveal high species richness (Margalef's d = 8.97) and diversity (Shannon Index H' = 3.526, Fisher alpha diversity a = 41.73). It concludes that the abundance of spider species at this study site was high and the evenness index was also high (e >0, e = 0.8944). These findings suggest the absence of stress elements in the study area. [ABSTRACT FROM AUTHOR]

Se reporta por primera vez a Tromatobia sp. (Hymenoptera: Ichneumonidae) asociada con Neoscona oaxacensis (Araneae: Araneidae), araña que exhibe cuidados maternos prolongados de sus sacos de huevos u ovisacos, en Toluca, Estado de México. El ichneumónido infestó 24% de los ovisacos individuales. No se documentó la presencia de huevos del ichneumónido en los ovisacos infestados. Las larvas de Tromatobia sp. consumieron la totalidad de los huevos de N. oaxacensis y próximas a pupar construyeron cocones individuales, colocándolos uno al lado del otro. Por cada ovisaco individual infestado de N. oaxacensis se encontraron dos a tres pupas y/o adultos de Tromatobia sp. Los adultos abandonaron el interior de los cocones a través de orificios de 2 mm de diámetro. Este estudio representa la primera interacción trófica que ocurre entre Tromatobia sp. y la araña Neoscona oaxacensis en México. Tromatobia sp. (Hymenoptera: Ichneumonidae) is reported for the first time associated with Neoscona oaxacensis (Araneae: Araneidae), a spider that exhibits prolonged maternal care of its egg sacs or ovisacs, in Toluca, State of Mexico. The ichneumonid infested 24% of individual ovisacs. The presence of ichneumonid eggs was not documented in the infested ovisacs. Larvae of Tromatobia sp. consumed all the eggs of N. oaxacensis and, close to pupating, built individual cocoons, placing them side by side. For each individual ovisac infested of N. oaxacensis, two to three pupae and/or adults were counted. Adults left the interior of the cocoons through 2 mm diameter holes. This study represents the first trophic interaction occurring between Tromatobia sp. and N. oaxacensis in Mexico. [ABSTRACT FROM AUTHOR]

Orb-web construction behaviour, a classic example of 'innate' behaviour, is highly flexible. Determining which cues guide construction behaviour is complicated by the strong correlations between some variables, and the difficulty of manipulating of some web variables in biologically realistic ways. This study utilized a new experimental technique, adding sticky lines to webs during construction, to examine cues that guide sticky spiral spacing. Deflections and subsequent reductions in spacing produced by experiments that involved relatively long radii resembled the reduced spacing pattern on short radii in control webs; radius length was thus not the cue eliciting reduced spacing in control webs. An alternative, that smaller inter-radius distances elicited reduced spacing, was supported by experimentally removing radii to increase the distances between radii. The new technique also elicited variation in responses that suggested that spiders may use mental cues such as memories or expectations of line positions to guide sticky spiral placement. [ABSTRACT FROM AUTHOR]

An invasive orb-weaving spider from east Asia is now spreading through the southeastern United States; Trichonephila clavata (the "jorō spider") makes large, imposing webs seemingly everywhere, including in urban landscapes, and even next to busy roads. However, areas near roads come with frequent disturbances, including auditory and vibrational, which for many animals, leads to physiological or behavioral changes. Here we tested if varying levels of road traffic affect the prey–capture behavior of jorō spiders in northeast Georgia. We visited roadsides that ranged in traffic density and exposed nearby jorō spiders to a simulated prey (a tuning fork at 128 hz frequency, touched to the web), and recorded whether or not the spider attacked it. Out of 357 total trials across 20 different roads, jorō spiders attacked the simulated prey 59% of the time, but at the local scale, there was high variability in this rate; at some roadsides, over 80% of the spiders attacked, while at others, less than 30% did. When all roads were considered collectively, there was a small but significant (negative) correlation between daily road traffic and spider attack rates. Put another way, spiders near moderate- to heavy-traffic roads were slightly less likely to attack than those near low-traffic roads (51% vs. 65%). Jorō spiders appear to be able to live near roads, but this does come with a cost in terms of prey capture. However, spiders near busier roads did not weigh less than those in other sites, suggesting they may be able to compensate for the disturbance. These findings add to the accumulating evidence around this species that points to its ability to exist in human-dominated landscapes, which will likely aid its spread in the introduced range. [ABSTRACT FROM AUTHOR]

The orb-weaver spider genus Gea C.L. Koch, 1843 from China is revised, and three species including one new species, are recognized: Gea jingdong Mi, Wang & Gan, sp. nov. (♂♀) from Yunnan; Gea spinipes C.L. Koch, 1843 (♂♀) from Guangdong, Guangxi, Guizhou, Hainan, Taiwan, and Yunnan; and Gea subarmata Thorell, 1890 (♂♀) from Guangxi and Hainan. Gea subarmata is newly recorded in China. [ABSTRACT FROM AUTHOR]

Simple Summary: Predators and prey have direct interactions that influence their short-term behaviors, including resource allocation and strategies for moving through habitats. However, the presently observed behaviors are the products of coevolutionary interactions, posited to be a history of measures and countermeasures between the predator and prey. We found that Argiope (orb-weaver) spiders in the continental USA appear to use a pheromone lure that mimics the mating pheromone of the day-flying Hemileuca moth (buck moth) to entice male moths into their webs. We found evidence that different phylogenetic groups of Hemileuca moths respond to the Argiope pheromone lure with a broad range of responses, ranging from indifferent to acutely strongly attracted, suggesting a coevolutionary history of predator–prey countermeasures. One of these countermeasures may be the potential evolution of moth developmental timing (adult emergence) to avoid Argiope predation in areas where the ranges of the moths and spiders overlap. Predator–prey coevolution, particularly chemo-ecological arms races, is challenging to study as it requires the integration of behavioral, chemical ecology, and phylogenetic studies in an amenable system. Moths of the genus Hemileuca (Saturniidae) are colorful, diurnal, and fast and often fly well above the vegetation canopy layer. However, several Hemileuca species have been reported as being captured in spider webs, specifically Argiope species (Araneidae). Female Hemileuca are known to produce mating pheromones and spiders of the Araneidae family are known to use pheromone lures to attract lepidopteran prey. We presented primarily female Argiope aurantia, which are attractive to male Anisota pellucida (Saturniidae), to different populations of Hemileuca species across the southern and western United States to categorize the homing response strength of different species of male Hemileuca. When we mapped these Argiope lure attraction strength categories onto the most recently published Hemileuca phylogeny, the behavioral patterns suggested a potential co-evolutionary arms race between predators and prey. Males of Hemileuca maia, H. grotei, and H. nevadensis (all in the same clade) appeared to have no attraction to A. aurantia, while H. magnifica and H. hera (within a different, separate clade) appeared to be strongly attracted to A. aurantia, but H. nuttalli (also within the H. hera and H. magnifica clade) displayed no attraction. Furthermore, Hemileuca eglanterina (yet a different clade) displayed strong, weak, and no attraction to A. aurantia, depending on the population. These apparent clade partitioning patterns of Argiope lure effectiveness and within-species variation in Hemileuca lure responses suggest a predator–prey coevolutionary history of measures and countermeasures. [ABSTRACT FROM AUTHOR]

In order to produce artificial silk fibers with properties that match the native spider silk we likely need to closely mimic the spinning process as well as fiber architecture and composition. To increase our understanding of the structure and function of the different silk glands of the orb weaver Larinioides sclopetarius, we used resin sections for detailed morphology, paraffin embedded sections for a variety of different histological stainings, and a histochemical method for localization of carbonic anhydrase activity. Our results show that all silk glands, except the tubuliform glands, are composed of two or more columnar epithelial cell types, some of which have not been described previously. We observed distinct regionalization of the cell types indicating sequential addition of secretory products during silk formation. This means that the major ampullate, minor ampullate, aciniform type II, and piriform silk fibers most likely are layered and that each layer has a specific composition. Furthermore, a substance that stains positive for polysaccharides may be added to the silk in all glands except in the type I aciniform glands. Active carbonic anhydrase was found in all silk glands and/or ducts except in the type I aciniform and tubuliform glands, with the strongest staining in aggregate glands and their ductal nodules. Carbonic anhydrase plays an important role in the generation of a pH gradient in the major ampullate glands, and our results suggest that some other glands may also harbor pH gradients. [ABSTRACT FROM AUTHOR]

Urban environments represent a theatre for life history evolution. Species able to survive in urban areas can adapt to the local and often divergent environmental conditions compared to rural or (semi‐)natural environments. Dispersal determines establishment, gene flow, and thus the potential for local adaptation. Since habitats in urban environments are highly fragmented, and showing substantial turnover, contrasting adaptive effects on dispersal are expected. Fragmentation selects against dispersal while patch turnover is expected to promote the evolution of dispersal. We here show both processes to act in concert when different scales are considered. Dispersal behavior of juvenile, lab‐reared garden spiders from three mid‐sized European cities were tested under standardized conditions. While long‐distance dispersal showed to be overall rare, short‐distance dispersal strategies increased with urbanization at small scales but declined when urbanization was quantified at large scales. We discuss the putative drivers behind these differences in natal dispersal and highlight its importance for urban evolution and ecology. [ABSTRACT FROM AUTHOR]

Climatic seasons have been shown to determine the temporal fluctuations in species communities of different ecosystems. Here, we assessed the diversity of spider assemblages in dry, transition and rainy seasons in the "Guillermo Piñeres" Botanical Garden (GPBG), Turbaco, Colombia. We collected spider assemblages between June 2018 and April 2019 through standardized day and night sampling methods for tropical ecosystems: looking up, looking down, beating and leaf litter sieving. In total, we collected 1585 individuals, belonging to 28 families and 112 (morpho) species. We calculated the effective species richness (Hill numbers) to evaluate the changes in diversity across seasons and used clustering and ordination methods (Jaccard index-based nMDS) to identify differences in the composition of the assemblages. Also, we compared the abundance and species richness of predatory guilds of the three seasons. The transition season showed the highest diversity with 94 morphospecies, an effective number of species of 48.7 and a dominance of 32.4 effective species. The clustering and ordination methods grouped the sampling events into three groups, each corresponding to a climatic season. The most abundant guild was the orb web weavers, with the highest value in the rainy season, while "other hunters" were the most species rich. Our results indicate that the spider assemblages in GPBG present a seasonal variation in diversity, probably influenced by climatic conditions. Understanding how these seasonal changes occur is necessary to develop forest management strategies for monitoring and management projects on the conservation of species assemblages according to the Convention on Biological Diversity. [ABSTRACT FROM AUTHOR]

We complement and expand the existing descriptions of the Australian araneid spider Paraplectanoides crassipes Keyserling, 1886, and provide the first detailed analysis of the male palpal homologies to include examination of the expanded organ and scanning electron micrographs of the palpal sclerites. We study the placement of Paraplectanoides and the classification of the family Araneidae by combining ultraconserved elements with Sanger markers. We also added Sanger sequences of the Australian araneid genus Venomius to the molecular dataset of Scharff et al. (2020) to explore the phylogenetic placement and implications for classification of the family. We evaluate a recent proposal on the classification of the family Araneidae by Kuntner et al. (2023) in which a new family is erected for P. crassipes. Paraplectanoides is monotypic. Examination of the type material shows that Paraplectanoides kochi O. Pickard-Cambridge, 1877 is misplaced in the genus and the name is a senior synonym of the araneid Isoxya penizoides Simon, 1887 (new synonymy) that results in the new combination Isoxya kochi (O. Pickard- Cambridge, 1877). The classification of Araneidae is revised and the following nomenclatural acts are introduced: Paraplectanoididae Kuntner, Coddington, Agnarsson and Bond, 2023 is a junior synonym of Araneidae Clerck, 1757 new synonymy; phonognathines and nephilines are subfamilies of Araneidae (Subfamily Phonognathinae Simon, 1894 rank resurrected; and Subfamily Nephilinae Simon, 1894 rank resurrected). The results of our analyses corroborate the sister group relationship between Paraplectanoides and the araneid subfamily Nephilinae. Venomius is sister to the Nephilinae + Paraplectanoides clade. The placement of the oarcine araneids and Venomius renders the family Araneidae non-monophyletic if this were to be circumscribed as in Kuntner et al. (2023). In light of the paucity of data that the latter study presents, and in absence of a robust, stable and more densely sampled phylogenetic analysis of Araneidae, the changes and definitions introduced by that classification are premature and could lead to a large number of new families for what once were araneid species if the maximum-crown-clade family definitions were to be used. Consequently, we argue for restoring the familial and subfamilial classification of Araneidae of Dimitrov et al. (2017), Scharff et al. (2020) and Kallal et al. (2020). [ABSTRACT FROM AUTHOR]

The orb-weaving spider Argiope trifasciata (Forsskål, 1775) was scientifically described in Egypt while it has been considered native to North America. The aim of this study was to analyse the phylogenetic relationships of the Egyptian population and shed light on its introduction and migration history. The COX1 gene (mtDNA) of 49 samples from Egypt and Cyprus was analysed with 168 additional COX1 sequences available in GenBank and BOLD originating from nineteen other countries. Selected ecological parameters were also studied in an Egyptian desert habitat for comparison with North American populations. We found that spiders oriented their webs in relation to the sun's position (South and South-East) most likely to regulate their body temperature. The life cycle of A. fasciata in Egypt was found to be extended from what has been reported from other populations, partly possible because some individuals may survive throughout the winter. The phylogenetic analysis revealed that the sequences from Egypt and Cyprus clustered with Afro-Eurasian populations. Thirty haplotypes were found in Egypt and Cyprus of which 21 were unique. The analysis further revealed that the nearest American COX1 sequence was separated by 18 mutations. The high COXI divergence (5.1%) as well as the low gene flow (Fst = 0.75) between Afro-Eurasian and American populations, indicated that A. trifasciata has not been recently dispersed from America to Africa and other continents, but the genetic isolation was estimated to have happened around 2.04 My ago. If these spiders represent unique species or subspecies will need further research. [ABSTRACT FROM AUTHOR]

This spider survey of a semidecidual forest area in the city of Mendes, in Rio de Janeiro state, Brazil, aims to increase the scant knowledge about spider communities in this Brazilian ecosystem. Samples were taken over a year, once every three months, in four different sites with seven sampling methods. An overall of 457 species/morphoespecies were recorded in 47 families, corresponding to 10,541 individuals sampled. Families with highest number of species were Theridiidae (91), Araneidae (72), and Salticidae (55). Families with highest abundance were Theridiidae (2,829 specimens), Pholcidae (2,328), and Araneidae (1,263). Most abundant species were Mesabolivar togatus(534), Carapoia lutea(499 individuals), and Cryptachaea digitus (387). Species accumulation curves indicate a minimum of 513 (Bootstrap) and a maximum of 653 species (Jackknife2) for sampled areas. Total Berger-Parker dominance index was low, 0.051, varying from 0.042 to 0.076, while total Pielou equitability Index was high, 0.805, ranging from 0.744 to 0.800. Total Shannon-Wiener diversity index was relatively high, 4.931, ranging from 4.559 to 4.899. The complex, very diverse and relatively well-structured spider community found in Mendes is remarkable, especially in an area with predominantly secondary forests and high anthropic influence. [ABSTRACT FROM AUTHOR]

The Okkarai area of Pachamalai hills, Eastern Ghats, Tiruchirappalli district, Tamil Nadu, India, was studied for spider diversity in the current study. In total, 178 spiders were recorded, belonging to 12 distinct families (Araneidae, Desidae, Linyphiidae, Nephilidae, Oxyopidae, Pholcidae, Pisauridae, Salticidae, Sparassidae, Tetragnathidae, Theridiidae and Thomisidae), and 17 and 20 different genera and species, respectively. Araneidae family dominated the spider population, and the family dominance curve was in the ascending order of Araneidae (25.28%) > Oxyopidae (14.04%) > Pholcidae (14.04%) > Thomisidae (10.11%) > Tetragnathidae (7.86%) > Linyphiidae (6.74%) > Nephilidae (6.17%) > Sparassidae (5.05%) > Theridiidae (4.49%) > Pisauridae (3.37) > Salticidae (2.24%) > Desidae (0.56%). Araneidae (17.64%) had the most genera per family, and Araneidae and Oxyopidae (20.00%) had the most species per family; and about species composition, Pholcus phalangioides dominated with 14.04%. Spider guilds were represented by web patterns as well as hunting patterns. Web pattern comprised orb web (60.86%), cobweb (34.78%) and sheet web (4.34%). Orb web was represented by families Araneidae, Nephilidae and Tetragnathidae; cobweb by Desidae, Pholcidae, Pisauridae and Theridiidae; while Linyphiidae for sheet web. Ambushers (53.22%) and stalkers (46.77%) represented the hunting pattern wherein Pisauridae, Sparassidae and Thomisidae represented ambushers, and Oxyopidae and Salticidae represented stalkers. Araneidae and Oxyopidae had high species richness indicated by Hill's (4), Margalef's (1.33), and Menhinick's (0.299) indices. Salticidae had high species evenness denoted by Alatalo's (0.578), Pielou's (0.488), Shannon's (1.471) and Sheldon's (1.413) indices; while Linyphiidae represented Heip's index (1.347). Araneidae scored high on other indices, viz., Berger-Parker dominance (25.28%), community dominance (1.24), and relative dominance (20.00%); while Salticidae had a high Hill's number abundance (1.413%), and Pholcidae had a high relative frequency (0.55). This study will contribute to the data on spider biodiversity, taxonomy, it's abundance, distribution, and community organization. [ABSTRACT FROM AUTHOR]

Economic and ecological consequences of invasive species make biological invasions an influential driver of global change. Monitoring the spread and impacts of non‐native species is essential, but often difficult, especially during the initial stages of invasion. The Jorō spider, Trichonephila clavata (L. Koch, 1878, Araneae: Nephilidae), is a large‐bodied orb weaver native to Asia, likely introduced to northern Georgia, U.S. around 2010. We investigated the nascent invasion of T. clavata by constructing species distribution models (SDMs) from crowd‐sourced data to compare the climate T. clavata experiences in its native range to its introduced range. We found evidence that the climate of T. clavata's native range differs significantly from its introduced range. Species distribution models trained with observations from its native range predict that the most suitable habitats in North America occur north of its current introduced range. Consistent with SDM predictions, T. clavata appears to be spreading faster to the north than to the south. Lastly, we conducted surveys to investigate potential ecological impacts of T. clavata on the diversity of native orb weaving spiders. Importantly, Trichonephila clavata was the most common and abundant species observed in the survey, and was numerically dominant at half of the sites it was present in. Our models also suggest that there is lower native orb weaver species richness and diversity closer to where T. clavata was initially found and where it has been established the longest, though human population density complicates this finding. This early study is the first to forecast how widely this spider may spread in its introduced range and explore its potential ecological impacts. Our results add evidence that T. clavata is an invasive species and deserves much more ecological scrutiny. [ABSTRACT FROM AUTHOR]

A checklist of 2265 spider species and subspecies, 495 genera and 71 families is provided. Data were extracted from the South African National Survey of Arachnida database and over 200 taxonomic revisions, ending December 2022. Global distributions, endemicity and conservation assessment using IUCN Criteria are provided for each species. A total of 1325 spp. are endemic to South Africa (58.5%), 126 spp. (5.6%) are of special concern and 693 spp. (30.6%) are Data Deficient (DD), while 15 species were described without exact locality data. Most species (1444 spp., 63.8%) are widely distributed with no known threats and are of Least Concern. A total of 1316 spp. (57.6%) are known from both sexes and 23 spp. (1.0%) were described from juveniles. Salticidae is the most speciesrich family (354 spp.), followed by Gnaphosidae (195 spp.), Thomisidae (143 spp.) and Araneidae (100 spp.) and ten families are represented by a single species. [ABSTRACT FROM AUTHOR]

Spider webs, and in particular orb webs, are among the most iconic characteristics of spider biology. The evolution of, and developmental changes in, orb webs have been well studied, but we still have a limited understanding of allometric relations between the size of orb webs and spider body size. In this study, we investigate this relationship using measurements from 55 individuals of two common orb-weaving spider (Araneidae) species in South Wales, UK. We recorded body size using two methods: direct measurements with calipers, and estimations from photographs using ImageJ software. We found that these two methods give almost identical measurements, supporting the use of image-based size measurement in many situations where this is advantageous. We also found evidence for negative allometry of orb web size (relative to spider body length), such that larger spiders build proportionately smaller webs. This implies that the 'giant webs' in some orb-weaver species must be the result of a fundamental shift in the constraints or advantages which result in the allometric relationships described here. [ABSTRACT FROM AUTHOR]

Female chemical signals are crucial for sexual communication in spiders and convey detailed information about females' mating status or age. However, evidence for chemical communication in spiders is largely behavioral. Only a few spider pheromones are known and quantitative chemical analyses of individual spiders are especially scarce. In the European wasp spider, Argiope bruennichi (Scopoli, 1772), females emit the volatile trimethyl methylcitrate, which attracts males from a distance. A recent study on the role of this pheromone in close-range male mate choice revealed that older virgin females approaching oviposition produce higher amounts of pheromone than younger ones, thereby increasing their attractiveness to males, and stop pheromone signaling shortly after copulation. Here we provide more detailed analyses of temporal dynamics in pheromone production in both virgin and mated female A. bruennichi. Our results corroborate previous observations indicating that male mating behavior in this species is guided by variation in female signaling effort. [ABSTRACT FROM AUTHOR]

The expressions of parental care can vary in space and time because factors driving offspring mortality depend on variable abiotic and biotic conditions. Manogea porracea is a spider that exhibits biparental care and widespread distribution in the Neotropical region. Parents can protect their offspring against abiotic conditions that may damage their webs, or compromise their egg sacs, and against araneophagic spiders that prey on their eggs. However, the current knowledge of the parental care in the species is restricted to a population located in areas covered by Eucalyptus plantations. This study investigates parental care efficiency in a new ecological context, a protected area of Brazilian savanna. We described the substrates in which M. porracea built webs and the agents of egg mortality. We also performed a parent removal experiment to test the effect of parental care on the integrity of nursery webs, offspring survival, and the presence of egg predators. Spiders built webs at variable heights and many distinct substrates but were mainly associated with the bromeliad Ananas ananassoides. We found two previously reported egg predators, Faiditus caudatus and Argyrodes elevatus (Araneae Theridiidae), and a new one emerging from the egg sacs, the insect Zeugomantispa virescens (Neuroptera Mantispidae). The presence of parents in the webs of M. porracea prevented the webs from collapsing and effectively increased offspring survival. However, the occurrence of egg predators was not reduced by the presence of parents. Overall, parental care increased offspring survival in both populations, but variation in biotic and abiotic factors between areas influenced offspring mortality and the efficiency of parental behaviours. Our results emphasise the importance of investigating multiple populations in behavioural studies of parental care. We investigated the efficiency of parental care of the spider M. porracea in a protected area of Brazilian savanna. Parents were efficient in increasing offspring survival and their presence assured the integrity of most nursery webs. Egg predators were found in webs regardless of the presence of parents and we registered for the first time the insect Zeugomantispa virescens within egg sacs. We discuss the implications of population variation for the ecology and evolution of parental care efficiency in M. porracea. [ABSTRACT FROM AUTHOR]

To explore the spider species diversity and its environmental associations on artificial grasslands in karst areas, we investigated the species diversity of spider in the New Zealand pasture of the Youshanhe in northwestern Guizhou Province, using sampling, trap, and line sampling methods, and further assessed species diversity–environment relationship. The results of the study showed: (1)1642 spiders, belonging to 15 families, 53 genera, and 69 species, were collected. The order of different functional groups was: Round-web spiders > Ambush spiders > wandering-spiders > Net-type spiders. The dominant four families were Araneidae (25.15% of all species), Theridiidae (20.52% of all species), Philodromidae (15.1% of all species), and Thomisidae (13.28% of all species). Furthermore, the two dominant species were Araneus diffinis (17.17% of all individuals) and Philodromus fallax (14.49% of all individuals). (2) The number of individual spiders, the number of species, and the Shannon-wiener index were the smallest in December, which was significantly lower than that in September, October, November and January. The spider richness index decreased first and then increased, and was the smallest in December, significantly lower than in September, October and January. (3) The linear fitting showed that altitude, air humidity, and number of vegetation species had significantly positive associations with spider abundance. (4) Canonical correspondence analysis revealed that 9 environmental factors accounted for 70.98% of the variation for spider species diversity. The vegetation Pielou index had a significantly negative associations with spider species diversity, and soil temperature and air temperature had a significant and positive effect on spider species diversity. Among them, soil temperature had the greatest impact on spider composition, with a contribution rate of 78.52%. The species diversity of spider communities on artificial grasslands in karst areas had a strong correlation with factors such as seasons, climate, and vegetation. Spiders must be closely integrated with local vegetation, climatic and soil factors to control grassland pests and diseases. [ABSTRACT FROM AUTHOR]

As a worldwide taxon inhabiting a diverse range of habitats and environmental conditions, bats also demonstrate some of the greatest variation in reproductive strategies of any mammalian order. Whilst monoestry is the predominant mating pattern of bats within the temperate zone, polyoestry and variants of this mode are more prevalent at tropical latitudes. As a tropical species occurring in a temperate climate in the southern extent of its range, the reproductive phenology of the golden-tipped bat (Phoniscus papuensis) is poorly understood. Here we present the first evidence of polyoestry in this species, an uncommon reproductive trait in Australian bats. The influence of weather and increase in prey density (orb-weaving spiders) are suggested as potential drivers for what appears to be a positive facultative breeding response to a pulse of resources. This observation demonstrates that there is still much to learn about the basic natural history and reproductive strategies of Australian bats. The reproductive traits in many Australian species of bat remain poorly known. We present the first evidence for multiple litters (polyoestry) in the golden-tipped bat. We discuss the tropical origins of golden-tipped bats and conditions which may have facilitated multiple births in the first breeding season following the 2019/2020 Black Summer fires. [ABSTRACT FROM AUTHOR]

Larinia elegans Spassky, 1939 is an orb-weaver (Araneidae) inhabiting reeds growing from shallow water bodies from central Europe to China. In Europe, it was previously only found in Austria, Hungary, Czechia, Ukraine and southern part of European Russia. In this study, we present the first record of this species for North Macedonia as well as further records from Czechia. We also provide a synthesis of the ecological data, supported by our observations. Additionally, we highlight its cryptic way of life and prompt arachnologists in surrounding countries to search for this species, which may have been overlooked in the past. [ABSTRACT FROM AUTHOR]

Myotis emarginatus seems fond of spiders and flies, a unique feeding style among European bats. The importance of each prey type varies among studies, so this paper aims to expand on the knowledge to unveil the trophic niche of M. emarginatus by studying its diet changes throughout the maternity season. We sampled five maternity colonies in the Basque Country every 2 weeks for the whole duration of the maternity season and studied their diet using DNA metabarcoding methods. We observed significant changes in diet diversity and composition. At the beginning of the season, M. emarginatus consumed a variety of prey orders, Diptera being the most abundant; but as the season progressed, the relative consumption of Araneae increased. By August, 80% of the weighted percentage of occurrences (wPOO) corresponded to the orb-web-building spider Araneus diadematus. Orb-web-building spiders need habitats of high vertical complexity to grow in abundance. Therefore, conserving them is essential to preserve attractive hunting grounds for colonies of M. emarginatus. Besides, diurnal flies, mainly Stomoxys calcitrans, were also considerably consumed in the colonies studied, which can become detrimental to the well-being of cattle, and can act as a vector of many diseases. [ABSTRACT FROM AUTHOR]

Six new species of the genus Araneus Clerck, 1757 from Fanjingshan National Nature Reserve in Guizhou Province, China are described: Araneus chenjingi sp. nov. (♂♀), and A. yuboi sp. nov. (♂♀) are assigned to the A. diadematus group; A. lihaiboi sp. nov. (♂♀), A. shii sp. nov. (♂♀), A. wanghuai sp. nov. (♂♀), and A. yangchuandongi sp. nov. (♂♀) are assigned to the A. sturmi group. Araneus colubrinus Song & Zhu, 1992 is redescribed. A new synonym of Araneus colubrinus Song & Zhu, 1992 is proposed: Araneus octodentalis Song & Zhu, 1992 syn. nov. [ABSTRACT FROM AUTHOR]

The eggs laid by the orb web spider Trichonephila clavata must overwinter in bitterly freezing and dry conditions before hatching, but there does not seem to be any protection like a compact silk case covering the entire eggmass. Instead, the surface of the eggmass is completely coated with a milky coating called chorionic microspheres (CM). Therefore, we investigated the fine structural characteristics of CM to demonstrate their ecological importance. Although the diameter of CM in outer eggmass exhibits a significant variation, the chorionic surface is coated with a single layer of CM, characterized by a consistent diameter of approximately 2.3 µm. The surface structure of aggregated CM shows short papillary projections demonstrating segmental adhesion of mucous components. CM is insoluble in water but partially soluble in anhydrous ethanol, and its spherical structure is completely decomposed by hexafluoroisopropanol (HFIP), a strong organic solvent. Since our fine structural observations clearly show that CM is not derived from vitellogenic or choriogenetic processes, the CM adhesive coatings during ovipositional process appears to be equivalent to cocoon silk for various protective functions in silken eggcase. [ABSTRACT FROM AUTHOR]

The large orb-weaving spider genus Araneus consists of numerous species with highly variable morphologies and behaviors, and phylogenetic analyses have suggested that the genus is polyphyletic. Here, we investigated the specimens of Araneus viridiventris Yaginuma 1969, A. noegeatus (Thorell 1895), and an undescribed species. They were morphologically similar to each other but differed from the type species of Araneus. Following our molecular phylogenetic analysis using the sequencing data of five genes, we describe a new genus, Leviaraneus n. gen., which contains these species. They are small spiders with a broad, green abdomen. Moreover, we described the unknown species as a new species, Leviaraneus halabala n. sp. Additionally, Leviaraneus noegeatus n. comb. is newly recorded from Thailand, and its male is described for the first time [ABSTRACT FROM AUTHOR]

Several traits of adult female Allocyclosa bifurca, including the forms and the colours of the dorsal and the ventral sides of the abdomen that match bumpy and smooth surfaces and associated colours of the two sides of the egg sac, the colours and positions of the spider's legs and the spiders' prey wrapping behaviour and their orientation of prey packages while they feed all increase the match with the overall shapes and colours of the egg sacs, visually camouflaging the spider at the hub of its orb. This camouflage is partially broken in two contexts: apparent attempts to avoid overheating in direct sunlight, and feeding. Neither a predatory bird nor a parasitoid wasp showed signs of being fooled by the camouflage. [ABSTRACT FROM AUTHOR]

Spiders have become a model group for sexual selection and mating system studies, but our understanding of courtship behavior in the group is heavily biased towards the infraorder Araneomorphae ('modern' spiders, such as orb weavers, jumping spiders, wolf spiders, crab spiders and many more). In the Mygalomorphae (tarantulas, trapdoor spiders, funnel‐web spiders and relatives), only a few descriptions of courtship are available and recent developments in the phylogenetics of the group offer an opportunity to remap and investigate the evolution of mating behaviors. Using 81 trials filmed in captivity, we report on the courtship behaviors of the iconic Sydney funnel‐web spider (Atracidae: Atrax robustus), which belongs to a large clade of biologically understudied mygalomorphs. Thirteen distinct behaviors are described for males, out of which at least two seem new to mygalomorphs, while four female behaviors are described. Moreover, the sequences of male behaviors are presented for when they come into contact with females inside or outside of their burrows. The mating positions of the pair, including details of how males use their legs and clasping spurs to grasp the females, are also presented. We discuss our results in a modern phylogenetic context, filling a gap in the understanding of sexual selection in the Mygalomorphae where such studies are rare and biased towards tarantulas. Finally, we attempt to consolidate descriptions of potentially homologous behaviors from several families in the group and offer insights into the evolution of cannibalism, male clasping spurs and female catalepsis (quiescence while mating). [ABSTRACT FROM AUTHOR]

Climate-driven changes in hydrological regimes are of global importance and are particularly significant in riparian ecosystems. Riparian ecosystems in California provide refuge to many native and vulnerable species within a xeric landscape. California Tetragnatha spiders play a key role in riparian ecosystems, serving as a link between terrestrial and aquatic elements. Their tight reliance on water paired with the widespread distributions of many species make them ideal candidates to better understand the relative role of waterways versus geographic distance in shaping the population structure of riparian species. To assist in better understanding population structure, we constructed a reference genome assembly for Tetragnatha versicolor using long-read sequencing, scaffolded with proximity ligation Omni-C data. The near-chromosome-level assembly is comprised of 174 scaffolds spanning 1.06 Gb pairs, with a scaffold N50 of 64.1 Mb pairs and BUSCO completeness of 97.6%. This reference genome will facilitate future study of T. versicolor population structure associated with the rapidly changing environment of California. [ABSTRACT FROM AUTHOR]