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Geographical barriers like mountain ranges impede genetic exchange among populations, promoting diversification. The effectiveness of these barriers in limiting gene flow varies between lineages due to each species' dispersal modes and capacities. Our understanding of how the Andes orogeny contributes to species diversification comes from well‐studied vertebrates and a few arthropods and plants, neglecting organisms unable to fly or walk long distances. Some arachnids, such as Gasteracantha cancriformis, have been hypothesized to disperse long distances via ballooning (i.e. using their silk to interact with the wind). Yet, we do not know how the environment and geography shape its genetic diversity. Therefore, we tested whether the Andes contributed to the diversification of G. cancriformis acting as an absolute or semi‐permeable barrier to genetic connectivity between populations of this spider at opposite sides of the mountain range. We sampled thousands of loci across the distribution of the species and implemented population genetics, phylogenetic, and landscape genetic analyses. We identified two genetically distinct groups structured by the Central Andes, and a third less structured group in the Northern Andes that shares ancestry with the previous two. This structure is largely explained by the altitude along the Andes, which decreases in some regions, possibly facilitating cross‐Andean dispersal and gene flow. Our findings support that altitude in the Andes plays a major role in structuring populations in South America, but the strength of this barrier can be overcome by organisms with long‐distance dispersal modes together with altitudinal depressions. [ABSTRACT FROM AUTHOR]

Redbacks are millisecond pulsar binaries with low-mass, irradiated companions. These systems have a rich phenomenology that can be used to probe binary evolution models, pulsar wind physics, and the neutron star mass distribution. A number of high-confidence redback candidates have been identified through searches for variable optical and X-ray sources within the localization regions of unidentified but pulsar-like Fermi -LAT gamma-ray sources. However, these candidates remain unconfirmed until pulsations are detected. As part of the TRAPUM project, we searched for radio pulsations from six of these redback candidates with MeerKAT. We discovered three new radio millisecond pulsars, PSRs J0838−2827, J0955−3947, and J2333−5526, confirming their redback nature. PSR J0838−2827 remained undetected for 2 yr after our discovery despite repeated observations, likely due to evaporated material absorbing the radio emission for long periods of time. While, to our knowledge, this system has not undergone a transition to an accreting state, the disappearance, likely caused by extreme eclipses, illustrates the transient nature of spider pulsars and the heavy selection bias in uncovering their radio population. Radio timing enabled the detection of gamma-ray pulsations from all three pulsars, from which we obtained 15-yr timing solutions. All of these sources exhibit complex orbital period variations consistent with gravitational quadrupole moment variations in the companion stars. These timing solutions also constrain the binary mass ratios, allowing us to narrow down the pulsar masses. We find that PSR J2333−5526 may have a neutron star mass in excess of 2 M⊙. [ABSTRACT FROM AUTHOR]

Mermithid parasitoids are well known to infect spiders; however, their impact on hosts and their taxonomic identity are still poorly analyzed. We present the first record of a mermithid nematode infection in the spider genera Piratula (Lycosidae) and Coelotes (Agelenidae), and in the species Alopecosa pulverulenta and Pardosa paludicola (Lycosidae). We describe the maldevelopment of the spiders' female genitalia induced by the parasitoid and summarize data on the impact of nematode parasitoids on spider development and behaviour. Phylogenetic analysis, based on the 18S rDNA, showed that spider parasitoidism arose independently in different branches of the phylogenetic tree of the family Mermithidae. [ABSTRACT FROM AUTHOR]

Venom plays a crucial role in the defense and predation of venomous animals. Spiders (Araneae) are among the most successful predators and have a fascinating venom composition. Their venom mainly contains disulfide-rich peptides and large proteins. Here, we analyzed spider venom protein families, utilizing transcriptomic and genomic data, and highlighted their similarities and differences. We show that spiders have specific combinations of toxins for better predation and defense, typically comprising a core toxin expressed alongside several auxiliary toxins. Among them, the CAP superfamily is widely distributed and highly expressed in web-building Araneoidea spiders. Our analysis of evolutionary relationships revealed four subfamilies (subA-subD) of the CAP superfamily that differ in structure and potential functions. CAP proteins are composed of a conserved CAP domain and diverse C-terminal domains. CAP subC shares similar domains with the snake ion channel regulator svCRISP proteins, while CAP subD possesses a sequence similar to that of insect venom allergen 5 (Ag5). Furthermore, we show that gene duplication and selective expression lead to increased expression of CAP subD, making it a core member of the CAP superfamily. This study sheds light on the functional diversity of CAP subfamilies and their evolutionary history, which has important implications for fully understanding the composition of spider venom proteins and the core toxin components of web-building spiders. [ABSTRACT FROM AUTHOR]

Spider ballooning is a phenomenon in which spiders employ silk threads to travel through the air for dispersal. While this behaviour has been extensively studied in agricultural areas, limited research has been conducted in urban environments, where green spaces are highly fragmented. However, in cities, aerial dispersal can be advantageous for spiders as it allows them to move to suitable habitat patches. This study aimed to investigate how the urban landscape affects spider ballooning.We collected ballooning spider samples using sticky traps in 10 urban sites within different landscape contexts. By using generalised linear models, we analysed the influence of vegetation cover at both local and landscape scales on spider abundance and family richness.Family composition was similar across the city regardless of the landscape context.More individuals were collected dispersing aerially in areas with low landscape‐level green cover. However, a higher local percentage of vegetation cover led to a substantial increase in aerial dispersal in areas with high landscape‐level green cover. Our findings highlight the significance of the interaction between vegetation cover at these two scales on aerial spider abundance.Our results support the hypothesis that generalist spiders exhibit increased ballooning in highly fragmented landscapes, actively seeking suitable habitats despite the elevated associated risk. Higher aerial dispersal in areas with greater local vegetation cover suggests an increase in short‐distance dispersal, indicating spiders' active search for better habitats nearby upon arrival at a site with potentially greater habitat availability. [ABSTRACT FROM AUTHOR]

Aim: Quantifying the relative contribution of environmental filtering versus limiting similarity in shaping communities is challenging because these processes often act simultaneously and their effect is scale‐dependent. Focusing on caves, island‐like natural laboratories with limited environmental variability and species diversity, we tested: (i) the relative contribution of environmental filtering and limiting similarity in determining community assembly in caves; (ii) how the relative contribution of these driving forces changes along environmental gradients. Location: Europe. Time period: Present. Major taxa studied: Subterranean spiders. Methods: We used data on distribution and traits for European cave spiders (n = 475 communities). We estimated the trait space of each community using probabilistic hypervolumes, and obtained estimations of functional richness independent of the species richness of each community via null modelling. We model functional diversity change along environmental gradients using generalized dissimilarity modelling. Results: Sixty‐three percent of subterranean spider communities exhibited a prevalence of trait underdispersion. However, most communities displayed trait dispersion that did not depart significantly from random, suggesting that environmental filtering and limiting similarity were both exerting equally weak or strong, yet opposing influences. Overdispersed communities were primarily concentrated in southern latitudes, particularly in the Dinaric karst, where there is greater subterranean habitat availability. Pairwise comparisons of functional richness across caves revealed these effects to be strongly scale‐dependent, largely varying across gradients of cave development, elevation, precipitation, entrance size and annual temperature range. Conversely, geographical distance weakly affected trait composition, suggesting convergence in traits among communities that are far apart. Main conclusions: Even systems with stringent environmental conditions maintain the potential for trait differentiation, especially in areas of greater habitat availability. Yet, the relative influence of environmental filtering and limiting similarity change with scale, along clear environmental gradients. The interplay of these processes may explain the assembly of species‐poor subterranean communities displaying high functional specialization. [ABSTRACT FROM AUTHOR]

Mesothelae, or primitively segmented trapdoor spiders, form the most basal clade among living spiders. In Southeast Asia, Liphistius is the only genus recognized in the extant family Liphistiidae. Liphistius taxonomy and species identification are based largely on characters of the genitalia; however, the female genitalia show high intraspecific variation, males are rarely collected, and the phylogenetic relationships among the 69 described Liphistius species are unresolved. Here, we focused on the Liphistius of Thailand, including 37 described and numerous undescribed species in four species groups. We generated sequences from five loci (COI , 16S, H3 , 28S, and ITS2) for 162 specimens from 52 sites in Thailand and Myanmar to reconstruct phylogenetic relationships, infer historical biogeography, and delimit species. The five-locus data set resolved nearly all species and species group relationships and was mostly congruent with morphology-based classifications. Ancestral area reconstruction suggested that Liphistius originated in Sibumasu (Siam–Burma–Malaysia–Sumatra) and diversified into several species groups, four (birmanicus , bristowei , linang , and trang) of which are found in Thailand. Speciation within Liphistius occurred in the area corresponding to their current distribution. All delimitation methods tested (ASAP, GMYC, PTP, STACEY and BFD) delimited specimens from discrete locations as separate species; variation in the number of species proposed (ranging from 53 to 72) stemmed from variation in delimitation of sympatric cryptic species. [ABSTRACT FROM AUTHOR]

We report a case of predation by a larger ctenid spider, Ancylometes terrenus, on a giant tadpole of Pseudis paradoxa. This event was observed in a temporary pond at the Ariri community, north of the municipality of Macapá, state of Amapá, eastern Brazilian Amazonia. This is the first record of A. terrenus preying upon P. paradoxa and the first record of this spider for the state of Amapá. This observation provides an interesting addition to prey-predator interactions between anurans and spiders. [ABSTRACT FROM AUTHOR]

that the plants exposed to red and blue light had higher growth rates and biomass compared to those exposed to white light. Continuous light exposure also resulted in increased growth and biomass. The study suggests that manipulating light conditions can enhance the growth and development of chamomile plants, potentially improving their cultivation and production.The fifth article discusses a study on the impact of climate change on the distribution of bird species in the Carpathian Mountains. The researchers used species distribution models to predict the potential range shifts of bird species under different climate change scenarios. The results show that many bird species are projected to experience range contractions and shifts to higher elevations. The study emphasizes the need for conservation efforts to mitigate the negative effects of climate change on bird populations.Overall, these articles provide valuable insights into various aspects of biology, including mammal diversity, wolf behavior, spider fauna, plant development, and bird distribution. The studies contribute to our understanding of biodiversity, conservation, and the impacts of environmental factors on different organisms. [Extracted from the article]

Habitat fragmentation is among the greatest threats to arachnids present in the forests, especially to Enoploctenus cyclothorax (Ctenidae), which is widely distributed in the Atlantic Forest of southern and southeastern Brazil. Fragmented populations, whether due to anthropic or stochastic factors, tend to be more susceptible to extinction, since genetic diversity is reduced in small and isolated populations. Considering this, the current work aimed to understand how the genetic variability is distributed in six populations of E. cyclothorax (120 individuals sampled), sampled in fragments of the Atlantic Forest in Paraná (Brazil), based on Single Nucleotide Polymorphism (SNP) genotyping. The results obtained support the separation of E. cyclothorax into two distinct genetic groups in the state, based mainly on analyses of genetic structure and connectivity. A strong and significant genetic structure was observed in the species, supported by the k = 3 estimated using Bayesian analysis, by the high values of FST genetic differentiation, and by the low gene flow identified between the genetic groups. Corroborating these results, isolation by distance and the presence of a genetic barrier in the evaluated populations were evidenced. Population genomic analysis also revealed non-homogeneous genetic diversity in E. cyclothorax (HE = 0.14 to 0.31). The hypothesis that population fragmentation could possibly impact the genetic variability of E. cyclothorax throughout the state was confirmed by the inferred data, which point to phytophysiognomy, geographical distance, and forest fragmentation as factors that shaped the current genetic structure identified in the evaluated populations. [ABSTRACT FROM AUTHOR]

It is important to have reliable information on the presence/absence, population structure, and density of animals across their natural range. Detecting small organisms, however, such as the Nearctic tree trunk sheetweaver spider Drapetisca alteranda Chamberlin 1909 (Araneae: Linyphiidae), presents challenges due to its diminutive size and cryptic nature. We used a capture/recapture study to determine the detection and recapture probabilities of this spider using a standard beat sheet technique adopted for surveying tree trunks. Spiders were released on 3 different tree species that provided a range of microhabitats, including variable bark surface area and furrow depth/width. Microhabitat features played a small role in the timing of spider recapture (i.e. slower rate of recapture as furrowing increased). However, our results demonstrated 100% detection across replicate experiments and individual recapture probabilities exceeding 90% in most situations, with no significant differences in recapture observed among tree species and with respect to tree circumference. Furthermore, we show that most spiders could be recaptured within 2 sampling revolutions around the tree trunk, and there was no difference in the probability of collecting male and female spiders (although they differ markedly in size). Finally, we found no difference among brushers, supporting the idea that this method is replicable across collectors and studies. Collectively, we establish confidence in the ecological knowledge obtained with this technique and encourage its application with similar species and systems. [ABSTRACT FROM AUTHOR]

Predatory arthropods play a crucial role in mitigating the impact of insect pests. However, the use of broad-spectrum insecticides in pest management methods can pose a threat to predator populations. In response to the need for safer and more selective insecticides that spare natural enemies, an effort was made to know the diversity of predatory fauna and effect of seed dressers and foliar spraying insecticides on coccinellids and spiders at the Main Agricultural Research Station in Dharwad, Karnataka, during the summer 2021 and 2022. The treatments included four seed treatments, four seed treatments in combination with foliar spray, two foliar sprays alone, and an untreated control. Predator numbers were recorded at 45 and 65 days after sowing (DAS), selecting 20 plants randomly in all treatments. The results demonstrated that during the summer 2021 and 2022, seed treatment with chlorpyriphos 20EC was identified as safe, exhibiting the highest number of coccinellids (0.55 and 1.33 per plant) and spiders (0.54 and 1.62 per plant), respectively. These results were statistically comparable to other treatments like, seed treatment with imidacloprid 60 FS (0.49 and 1.00 coccinellids per plant) (0.48 and 1.38 spiders per plant), thiamethoxam 30 FS (0.45 and 0.95 coccinellids per plant) (0.44 and 1.22 spiders per plant) during 2021 and 2022 summer, respectively, ranking just below the untreated control. A significant difference in the population of coccinellids and spiders was observed among all the treatments, with seedtreated plants recording the highest predatory populations compared to foliarsprayed plants. Consequently, the study concludes that seed treatment chemicals prove to be safer for predators while still effectively providing necessary pest control. This highlights the potential of integrating such seed treatment methods into pest management strategies to enhance overall efficacy while minimizing adverse effects on beneficial predator populations. [ABSTRACT FROM AUTHOR]

Arthropod faunas have become impoverished in recent years in abundance as well as in diversity, but so far little evidence exists concerning spiders. In 2022, we repeated pitfall trap collections of spider assemblages completed 25 years previously in coastal dune habitats of the Hanstholm Reserve of National Park Thy, Denmark. Traps were placed approximately at the same spots, i.e. the habitats (white dune, grey dune, dry dune heathland, wet dune heathland, low pine plantation) were represented approximately as before. Contrary to most previous reports of insect decline, we found only weak evidence of reduction in abundance, but strong indications of reductions in faunistic value based on changes in ecological traits. Within the same period of spring and with the same number of traps, we collected 12% fewer spider individuals and 13% fewer species; rarefaction indicated that the lowered species richness was real. Species diversity had decreased and dominance increased. Changes in indices of ecological traits showed that the fauna had changed into decreased contribution of habitat specialists and species of restricted Danish distribution; the proportion of aeronauts had increased; the average body size had decreased. Indices of assemblage microclimatic niche positions and niche widths showed increased representation of shade and humidity loving species. Most of these changes were repeated in each of the habitats. Finally, we found evidence of a phenological shift towards activity earlier in spring in some species. Implications for insect conservation: We discuss possible management measures to counteract the observed trend towards reduced faunistic value. [ABSTRACT FROM AUTHOR]

Studies on the effects of grazing disturbances in grasslands have shown mixed results for spider diversity, mainly regarding their guilds. While ungrazing, low, and moderate grazing potentially enhance the diversity of orb-weavers in spider communities, heavy grazing seems to reduce species' richness. On the population level though, studies of orb-weavers are scarce, and the effects of grazing in natural grasslands are unknown. In this way, we investigated the effects of different grazing levels on population persistence of orb-weaver spiders, hypothesizing that low to intermediate disturbances benefit populations. We predict that high grazing, due to the removal of vegetation structure, will negatively affect the occupancy and abundance of orb-weavers. For that, we experimentally controlled grazing pressure and obtained population occurrence and counts of two orb-weaver spider species, Argiope argentata and Alpaida quadrilorata. We found that A. argentata was negatively affected by grazing, as it relies on higher vegetation for web-building. In contrast, A. quadrilorata, which occurs in cattle-resistant rosette plants, showed no effects of grazing. Implications for insect conservation: Our study emphasizes the need for balanced grazing practices and habitat conservation to protect orb-weaver spiders and other arthropods, as well as species-specific effects for species from the same guild, underscoring their ecological significance in maintaining ecosystem stability. [ABSTRACT FROM AUTHOR]

Background: Only two Otacilia Thorell, 1897 species with troglobitic characteristics have been recorded from Laos and no records of troglobitic Otacilia species from China. New information: A new troglobitic species is reported from Guangxi, China: Otacilia khezu Lin & Li, sp. nov. (♂♀). Photos and morphological descriptions of the new species are presented; the type specimens of the new species are deposited in the Institute of Zoology, Chinese Academy of Sciences (IZCAS), Beijing. [ABSTRACT FROM AUTHOR]

Background: China exhibits remarkable diversity of the spider genus Belisana Thorell, 1898, with 62 species recorded to date. However, the largest number of Belisana species was found in Yunnan Province (23 ssp.), while only seven species were found in Guizhou Province. New information: In this paper, Belisana wangchengi sp. nov. as a new species is described from Guizhou Province, China. [ABSTRACT FROM AUTHOR]

Background: Domitius lusitanicus (Fage, 1931) is a troglobiont spider, endemic from caves in the largest karst massif in Portugal, the Estremenho. It was the first described cave-adapted species from Portugal, but the male of the species was only described in 1988. New information: Over the last two decades, the knowledge on the distribution of D. lusitanicus increased significantly. We assess the conservation status of D. lusitanicus, providing new information on its extent of occurrence and the anthropogenic threats and present a IUCN Red List profile. D. lusitanicus faces various anthropogenic threats, such as habitat loss, agriculture, pollution and tourism impacts. Despite a large part of its distribution is included in a Natural Park, it expands outside of the areas deemed for protection in the Natura 2000 network. This species has the widest spread distribution of all troglobionts in the Estremenho Massif; therefore, it may be used as an umbrella species for the protection of other cave-adapted species of invertebrates of the massif. [ABSTRACT FROM AUTHOR]

Background: Urbanisation is a rapidly growing global phenomenon leading to habitat destruction, fragmentation and degradation. However, urban areas can offer opportunities for conservation, particularly through the presence of green spaces which can even provide important habitats for imperilled species. Spiders, which play crucial roles in ecosystem functioning, include many species that can successfully exploit urban environments. Placed in the middle of the Mediterranean global biodiversity hotspot, Italy possesses an exceptionally rich spider fauna, yet comprehensive data on urban spider communities are still limited. More information on urban spiders in Italy would be extremely beneficial to support conservation efforts, especially in central and southern Italy, where knowledge on the spider fauna is largely incomplete. New information: The current study focused on the spider diversity of a large protected area (Appia Antica Regional Park) in urban Rome, Italy. A total of 120 spider species belonging to 83 genera and 28 families were identified, with 70 species being new records to the Province of Rome, 39 to the Latium Region and two (Pelecopsis digitulus Bosmans & Abrous, 1992 and Palliduphantes arenicola (Denis, 1964)) to Italy. Forty-one species were recorded during autumn/winter sampling and 107 in spring/ summer. The spider fauna recorded from the study area included about 37% of the total spider fauna known from the Province of Rome, 28% of that of the Latium Region and 7% of the entire Italian territory. The most represented families in terms of species richness were Gnaphosidae and Linyphiidae, which accounted for more than 40% of the sampled fauna. Lycosidae were the most abundant family (29% of captured individuals), followed by Zodariidae (16% of captured individuals), Linyphiidae (13% of captured individuals) and Gnaphosidae (7.5% of captured individuals). From a biogeographical point of view, most of the collected species belonged to chorotypes that extend for large areas across Europe and the Mediterranean. The research highlights the role of urban green spaces as refuges for spiders and the importance of arachnological research in urban areas as sources of information on spider biodiversity at larger scales. [ABSTRACT FROM AUTHOR]

Elevational gradients constitute excellent systems for understanding the mechanisms that generate and maintain global biodiversity patterns. Climatic gradients associated with elevation show strong influence on species distribution in mountains. The study of mountains covered by the same habitat type is an ideal scenario to compare alternatives to the energy hypotheses. Our aim was to investigate how changes in climatic conditions along the elevational gradient drive α- and β-diversity of four taxa in a mountain system located within a grassland biome. We sampled ants, spiders, birds and plants, and measured climatic variables at six elevational bands (with 10 sampling sites each) established between 470 and 1,000 masl on a mountain from the Ventania Mountain System, Argentina. Species richness per site and β-diversity (turnover and nestedness) between the lowest band and upper sites were estimated. For most taxa, species richness declined at high elevations and energy, through temperature, was the major driver of species richness for ants, plants and birds, prevailing over productivity and water availability. The major β-diversity component was turnover for plants, spiders and birds, and nestedness for ants. The unique environmental conditions of the upper bands could favour the occurrence of specialist and endemic species. [ABSTRACT FROM AUTHOR]

Three modules viz., M1 - integrated pest management (IPM) module, M2 - bio-intensive pest management (BIPM) module and M3 - farmer’s routine pest management module formulated against insect pests of okra were evaluated simultaneously at two locations to know their impact on spider and coccinellid predators. Seven and two species of spiders and coccinellids, respectively, were recorded. Pooled data revealed that BIPM module was found to be safe for the predators. [ABSTRACT FROM AUTHOR]

The Burmese lynx spider, Oxyopes birmanicus Thorell (Araneae: Oxyopidae) is one of the endemic and entomophagous predatory arthropod species in India. This present study describes the seasonal abundance, vertical distribution, and feeding behaviour of O. birmanicus on nymph (4th/5th instar) and the adults of the tea mosquito bug, Helopeltis theivora Waterhouse (Hemiptera: Miridae) under laboratory conditions. The seasonal abundance of the O. birmanicus spider was considerably high from June to November and low from January to April. The abundance of O. birmanicus significantly correlated with the TMB infestation percentage. In a vertical distribution study, the O. birmanicus spider largely preferred the top level of the tea bush, the observed population was shared by the top and middle levels with 76% and 24% respectively. The feeding potential of the female O. birmanicus spider was significantly higher than the male and egg-guarding female. Both, male and egg-guarding female O. birmanicus showed on-par feeding efficacy. The study found that O. birmanicus was an efficient predator against TMB and the results may be useful in developing an integrated pest management strategy for TMB. [ABSTRACT FROM AUTHOR]

Higher-level classifications often must account for monotypic taxa representing depauperate evolutionary lineages and lacking synapomorphies of their better-known, well-defined sister clades. In a ranked (Linnean) or unranked (phylogenetic) classification system, discovering such a depauperate taxon does not necessarily invalidate the rank classification of sister clades. Named higher taxa must be monophyletic to be phylogenetically valid. Ranked taxa above the species level should also maximize information content, diagnosability, and utility (e.g., in biodiversity conservation). In spider classification, families are the highest rank that is systematically catalogued, and incertae sedis is not allowed. Consequently, it is important that family-level taxa be well defined and informative. We revisit the classification problem of Orbipurae, an unranked suprafamilial clade containing the spider families Nephilidae, Phonognathidae, and Araneidae sensu stricto. We argue that, to maximize diagnosability, information content, conservation utility, and practical taxonomic considerations, this splitting scheme is superior to its recently proposed alternative, which lumps these families together as Araneidae sensu lato. We propose to redefine Araneidae and recognize a monogeneric spider family, Paraplectanoididae fam. nov. to accommodate the depauperate lineage Paraplectanoides. We present new subgenomic data to stabilize Orbipurae topology which also supports our proposed family-level classification. Our example from spiders demonstrates why classifications must be able to accommodate depauperate evolutionary lineages, for example, Paraplectanoides. Finally, although clade age should not be a criterion to determine rank, other things being equal, comparable ages of similarly ranked taxa do benefit comparative biology. [Classification, family rank, phylogenomics, systematics, monophyly, spider phylogeny.].

(1) Urbanization threatens biodiversity, yet urban native plants support native biodiversity, contributing to conservation and ecosystem services. Within urban agroecosystems, where non-native plants are abundant, native plants may boost the abundance and richness of beneficial arthropods. Nevertheless, current information focuses on pollinators, with little attention being paid to other beneficials, like natural enemies. (2) We examined how the species richness of native plants, garden management, and landscape composition influence the abundance and species richness of all, native, and non-native bees, ladybeetles, ants, and ground-foraging spiders in urban agroecosystems (i.e., urban community gardens) in California. (3) We found that native plants (~10% of species, but only ~2.5% of plant cover) had little influence on arthropods, with negative effects only on non-native spider richness, likely due to the low plant cover provided by native plants. Garden size boosted native and non-native bee abundance and richness and non-native spider richness; floral abundance boosted non-native spider abundance and native and non-native spider richness; and mulch cover and tree and shrub abundance boosted non-native spider richness. Natural habitat cover promoted non-native bee and native ant abundance, but fewer native ladybeetle species were observed. (4) While native plant richness may not strongly influence the abundance and richness of beneficial arthropods, other garden management features could be manipulated to promote the conservation of native organisms or ecosystem services provided by native and non-native organisms within urban agroecosystems.

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.

The paper reports on spiders captured in various heathland, bog and forest habitats during an expedition to the islands of Hitra and Frøya and the Froan archipelago in coastal parts of Central Norway by the Museum of Natural History and Archaeology. A total of 81 species from 17 families were found, based on material from both pitfall traps and manual collecting. No less than 14 species have never before been found in Trøndelag and two new families are also recorded (Liocranidae and Mimetidae). The species associations of the remote archipelago of Froan show large similarities to the fauna of the larger islands and the mainland and an island effect is not clearly seen. Typical forest species are established on the only forested island of the Froan archipelago, the majority of which were not found in other sites. The spider fauna of the bogs, heaths and forests are largely similar in composition to that reported from coastal islands in western parts of Hordaland.

Abstract Background The knowledge about the species of a habitat (both resident and transient/dominant and rare) is a vital step to plan the conservation measures. Being generalist predators, spiders help controlling the population of their prey and maintain ecosystem stability. This makes spiders excellent bio-indicators for assessing the impact of anthropogenic disturbance factors on natural ecosystems (De, Siliwal, Uniyal and Hussain in Trop. Ecol. 63: 1–7, 2021). The aim of this study was to assess the dominance structure and constancy of spiders in three different habitats (Sand dunes, Riparian and Rocky) of the Thar desert. Study was conducted from March 2017 to February 2019 covering all seasons. Results The eudominant species in sand dunes and rocky desert belonged to the family Thomisidae. These species were Tmarus sp. 1 and Tmarus kotigeharus Tikader, 1963, respectively. There were two eudominants in Riparian habitat (Oecobius putus O. Pickard-Cambridge, 1876 and Menemerus bivittatus (Dufour, 1831)). Through the analysis of constancy of all the species in the Thar desert, it was revealed that three species were constant in all the three habitats. The number of accessory and accidental species was far higher than constant species in all the habitats. Conclusions The number of accessory and accidental spider species in all habitats was far higher than constants due to the unstability of spider population. Therefore, this study highlights the necessity for conservation of these habitats of the Thar desert.

ABSTRACTMelting glaciers give a unique possibility to study how life colonizes newly exposed ground. Research during the last two decades has shown that arthropods play a key role in establishing the first functioning ecosystems. However, there are still gaps in our knowledge about this succession process and a need to identify key research directions. Good case studies are the basis for a general understanding of patterns and driving forces in primary succession. We present remarks and advice on this topic, using examples from European studies. We explore the driving forces supporting the early ecosystem, discuss the ability of certain micro- and macroarthropods to be pioneers, and highlight the autecology of pioneer species and their role in building early trophic networks. Relevant research questions are identified. Different colonization patterns are discussed, and we stress the importance of a geoecological approach to the succession. We discuss relevant methods to collect sufficient material, how to tackle the scale problem and “ecological noise,” and the importance of a good taxonomic resolution. The present “package” of updated knowledge, research questions, and advice about fieldwork practice is meant especially for ecologists who are in their early phase of investigating succession in glacier forelands.

Brown spider envenomation results in dermonecrosis, characterized by an intense inflammatory reaction. The principal toxins of brown spider venoms are phospholipase-D isoforms, which interact with different cellular membrane components, degrade phospholipids, and generate bioactive mediators leading to harmful effects. The Loxosceles intermedia phospholipase D, LiRecDT1, possesses a loop that modulates the accessibility to the active site and plays a crucial role in substrate. In vitro and in silico analyses were performed to determine aspects of this enzyme's substrate preference. Sphingomyelin d18:1/6:0 was the preferred substrate of LiRecDT1 compared to other Sphingomyelins. Lysophosphatidylcholine 16:0/0:0 was preferred among other lysophosphatidylcholines, but much less than Sphingomyelin d18:1/6:0. In contrast, phosphatidylcholine d18:1/16:0 was not cleaved. Thus, the number of carbon atoms in the substrate plays a vital role in determining the optimal activity of this phospholipase-D. The presence of an amide group at C2 plays a key role in recognition and activity. In silico analyses indicated that a subsite containing the aromatic residues Y228 and W230 appears essential for choline recognition by cation-π interactions. These findings may help to explain why different cells, with different phospholipid fatty acid compositions exhibit distinct susceptibilities to brown spider venoms.

The introduction of new species can have unpredictable effects on native communities. Understanding the potential for competitive interactions between widow spiders (Theridiidae: Latrodectus), and how they may have shaped species’ geographic distributions, is critical for predicting the impacts of biological invasions in this historically cryptic group. North America is home to three native widows (L. hesperus, L. mactans, L. variolus) and one invasive widow (L. geometricus) with distributions that are at least partly sympatric. Given the relative novelty of L. geometricus in native communities as they expand their range, it is unclear if and how they share resources with their congeners, and competition for climatic resources (space) could result in ecological impacts to native widows. Here we aim to model niche differentiation and niche dynamics between native widows, that have coevolved over time, and between native and brown widows to assess the potential for ecological impact. We investigated the potential for climatic niche partitioning to shape sympatric geographic distributions of native widows compared to each other and to L. geometricus. We aggregated photographed occurrences from social media communities and online repositories to quantify climatic niche overlap for all four species on a continental scale, to assess niche dynamics among native species and between invasive and nativespecies. We found that native species had distributions that were more strongly partitioned, showing weaker niche overlap, except for the two eastern widows, which showed strong overlap and niche equivalency. Conversely, we found greater niche overlap between L. geometricus and native widows, possibly because it is too soon to see the effect of competition on species’ geographic distributions, or because differences in diet or partitioning of urban versus nonurban microhabitats promote coexistence.

Background: The knowledge about the species of a habitat (both resident and transient/dominant and rare) is a vital step to plan the conservation measures. Being generalist predators, spiders help controlling the population of their prey and maintain ecosystem stability. This makes spiders excellent bio-indicators for assessing the impact of anthropogenic disturbance factors on natural ecosystems (De, Siliwal, Uniyal and Hussain in Trop. Ecol. 63: 1–7, 2021). The aim of this study was to assess the dominance structure and constancy of spiders in three different habitats (Sand dunes, Riparian and Rocky) of the Thar desert. Study was conducted from March 2017 to February 2019 covering all seasons. Results: The eudominant species in sand dunes and rocky desert belonged to the family Thomisidae. These species were Tmarus sp. 1 and Tmarus kotigeharus Tikader, 1963, respectively. There were two eudominants in Riparian habitat (Oecobius putus O. Pickard-Cambridge, 1876 and Menemerus bivittatus (Dufour, 1831)). Through the analysis of constancy of all the species in the Thar desert, it was revealed that three species were constant in all the three habitats. The number of accessory and accidental species was far higher than constant species in all the habitats. Conclusions: The number of accessory and accidental spider species in all habitats was far higher than constants due to the unstability of spider population. Therefore, this study highlights the necessity for conservation of these habitats of the Thar desert. [ABSTRACT FROM AUTHOR]

Although urbanisation is one of the greatest threats to biodiversity, its effect on particular invertebrate groups remains ambiguous on local and landscape scales. We aimed to analyse the effect of urban grassland management on spiders (Araneae) and carabids (Coleoptera: Carabidae), as well as other local and landscape parameters. We investigated 27 grasslands of two different management intensities (‘extensive’: one to two late cuts with removal of biomass [n = 18]; ‘intensive’: three to five mulching cuts [n = 9]) in the city of Karlsruhe, Germany. Pitfall trapping and sweep netting were performed to sample carabids and spiders. Results indicate that urban grasslands in Karlsruhe are inhabited by species‐rich assemblages, including several species of conservation concern (cc). Latter remain mostly restricted to dry grassland. The number of total specimens and of those belonging to species of cc were negatively affected by intensive management. The number of specimens of species of cc further decreased with increasing humidity and in spiders, additionally, by vegetation height. Landscape factors had limited effects, and only isolation of meadows negatively influenced the species richness of carabids (total and of species of cc). Our results demonstrate that conservation of dry grasslands in urban areas is crucial for sustaining local arthropod communities. Dry urban grassland may also act as a refugium for species of cc and mitigate the global insect crisis on a local and regional scale. In conclusion, biodiversity‐friendly mowing regimes should be applied on a broader scale in urban areas and target especially dry grassland plots. In addition, increasing connectivity and permeability of the urban matrix assist the colonisation by species of cc. [ABSTRACT FROM AUTHOR]

An accurate assessment of species diversity is a cornerstone of biology and conservation. The lynx spiders (Araneae: Oxyopidae) represent one of the most diverse and widespread cursorial spider groups, however their species richness in Asia is highly underestimated. In this study, we revised species diversity with extensive taxon sampling in Taiwan and explored species boundaries based on morphological traits and genetic data using a two-step approach of molecular species delimitation. Firstly, we employed a single COI dataset and applied two genetic distance-based methods: ABGD and ASAP, and two topology-based methods: GMYC and bPTP. Secondly, we further analyzed the lineages that were not consistently delimited, and incorporated H3 to the dataset for a coalescent-based analysis using BPP. A total of eight morphological species were recognized, including five new species, Hamataliwa cordivulvasp. nov., Hamat. leporaurissp. nov., Tapponia auriolasp. nov., T. parvasp. nov. and T. rarobulbussp. nov., and three newly recorded species, Hamadruas hieroglyphica (Thorell, 1887), Hamat. foveata Tang & Li, 2012 and Peucetia latikae Tikader, 1970. All eight morphological species exhibited reciprocally monophyletic lineages. The results of molecular-based delimitation analyses suggested a variety of species hypotheses that did not fully correspond to the eight morphological species. We found that Hamat. cordivulvasp. nov. and Hamat. foveata showed shallow genetic differentiation in the COI, but they were unequivocally distinguishable according to their genitalia. In contrast, T. parvasp. nov. represented a deep divergent lineage, while differences of genitalia were not detected. This study highlights the need to comprehensively employ multiple evidence and methods to delineate species boundaries and the values of diagnostic morphological characters for taxonomic studies in lynx spiders. [ABSTRACT FROM AUTHOR]

Spiders are a diverse order of chelicerates that diverged from other arthropods over 500 million years ago. Research on spider embryogenesis, particularly studies using the common house spider Parasteatoda tepidariorum, has made important contributions to understanding the evolution of animal development, including axis formation, segmentation, and patterning. However, we lack knowledge about the cells that build spider embryos, their gene expression profiles and fate. Single-cell transcriptomic analyses have been revolutionary in describing these complex landscapes of cellular genetics in a range of animals. Therefore, we carried out single-cell RNA sequencing of P. tepidariorum embryos at stages 7, 8 and 9, which encompass the establishment and patterning of the body plan, and initial differentiation of many tissues and organs. We identified 20 cell clusters, from 18.5 k cells, which were marked by many developmental toolkit genes, as well as a plethora of genes not previously investigated. We found differences in the cell cycle transcriptional signatures, suggestive of different proliferation dynamics, which related to distinctions between endodermal and some mesodermal clusters, compared with ectodermal clusters. We identified many Hox genes as markers of cell clusters, and Hox gene ohnologs were often present in different clusters. This provided additional evidence of sub- and/or neo-functionalisation of these important developmental genes after the whole genome duplication in an arachnopulmonate ancestor (spiders, scorpions, and related orders). We also examined the spatial expression of marker genes for each cluster to generate a comprehensive cell atlas of these embryonic stages. This revealed new insights into the cellular basis and genetic regulation of head patterning, hematopoiesis, limb development, gut development, and posterior segmentation. This atlas will serve as a platform for future analysis of spider cell specification and fate, and studying the evolution of these processes among animals at cellular resolution. [ABSTRACT FROM AUTHOR]

Oil palm plantations are typically managed in a monoculture system over large areas. This system contributes to biodiversity loss and promotes pest outbreaks by reducing natural enemies. However, ecosystem functions in oil palm plantations vary spatially and temporally and can still support biodiversity under certain conditions. We conducted a study on the species richness, abundance and species composition of natural enemies in oil palm plantations and investigated the factors influencing natural enemy communities in oil palm plantations at both local and landscape scales. We selected 12 sites in an oil palm plantation in Central Borneo, Indonesia, which were grouped into 4 sub‐areas based on the presence of natural habitats, which varied in local and landscape characteristics. Arthropods were sampled using canopy knockdown fogging with a pyrethroid insecticide. Different taxa of natural enemies responded differently to changes in habitat characteristics within oil palm plantations. Species richness of spiders was not affected by either local or landscape scale, but their species composition was affected by oil palm tree age (local scale) and the total edge of dominant oil palm tree age (landscape scale). Ant species richness was influenced by the class area of natural habitat (landscape scale), whereas their species composition was not influenced by either local or landscape scale. On the other hand, species richness of parasitoid wasps was influenced by light intensity (local scale) and the variation of oil palm tree age within a landscape (landscape scale). However, their species composition was only affected by light intensity. The results suggest that oil palm management practices need to consider both local and landscape scales to maintain biodiversity and biological control and to achieve sustainable management of oil palm plantations. [ABSTRACT FROM AUTHOR]

Spiders host a diverse range of bacteria in their guts and other tissues, which have been found to play a significant role in their fitness. This study aimed to investigate the community diversity and functional characteristics of spider-associated bacteria in four tissues of Heteropoda venatoria using HTS of the 16S rRNA gene and culturomics technologies, as well as the functional verification of the isolated strains. The results of HTS showed that the spider-associated bacteria in different tissues belonged to 34 phyla, 72 classes, 170 orders, 277 families, and 458 genera. Bacillus was found to be the most abundant bacteria in the venom gland, silk gland, and ovary, while Stenotrophomonas, Acinetobacter, and Sphingomonas were dominant in the gut microbiota. Based on the amplicon sequencing results, 21 distinct cultivation conditions were developed using culturomics to isolate bacteria from the ovary, gut, venom gland, and silk gland. A total of 119 bacterial strains, representing 4 phyla and 25 genera, with Bacillus and Serratia as the dominant genera, were isolated. Five strains exhibited high efficiency in degrading pesticides in the in vitro experiments. Out of the 119 isolates, 28 exhibited antibacterial activity against at least one of the tested bacterial strains, including the pathogenic bacteria Staphylococcus aureus, Acinetobacter baumanii, and Enterococcus faecalis. The study also identified three strains, GL312, PL211, and PL316, which exhibited significant cytotoxicity against MGC-803. The crude extract from the fermentation broth of strain PL316 was found to effectively induce apoptosis in MGC-803 cells. Overall, this study offers a comprehensive understanding of the bacterial community structure associated with H. venatoria. It also provides valuable insights into discovering novel antitumor natural products for gastric cancer and xenobiotic-degrading bacteria of spiders. [ABSTRACT FROM AUTHOR]

Four new species of Yunguirius B. Li, Zhao & S.Q. Li, 2023 are described from China, namely: Yunguirius parvus Wei & Liu, sp. nov. (♀), Yunguirius trigonus Wei & Liu, sp. nov. (♀), Yunguirius wangqiqiae Wei & Liu, sp. nov. (♀), and Yunguirius xiannushanensis Wei & Liu, sp. nov. (♀). [ABSTRACT FROM AUTHOR]

Large‐scale barcoding projects help to aggregate information on genetic variability of multiple species throughout their ranges. Comparing DNA sequences of both non‐conspecific and conspecific individuals from distant parts of their ranges helps to compare level of genetic isolation‐by‐distance patterns in different species and adaptive types. We compared mitochondrial CO1 gene sequences of 223 spiders from Georgia (Caucasus), representing 124 species and eight families, with 3097 homological sequences from spiders mostly from Europe, but also from other parts of the World. In most families, a significant isolation‐by distance pattern was observed on family level. On species level, a significant isolation‐by‐distance was observed in 40 species, although this low proportion is most likely related to a lack of data. Simultaneously, remarkable differences in spatial structure were shown for different species. Although the majority of the studied species have a broad western Palearctic range, web‐building spiders from families Araneidae, Theridiidae, and Linyphiidae are less isolated spatially than flower spiders (Thomisidae), jumping spiders (Salticidae), wolf spiders (Lycosidae), sac spiders (Clubionidae), and ground spiders (Gnaphosidae). This pattern is related with more common ballooning in web building than in actively hunting spiders, which commonly remain isolated since preglacial time. Ground spiders build the most isolated populations in the Caucasus. [ABSTRACT FROM AUTHOR]

Chelicerae, distinctive feeding appendages in chelicerates, such as spiders, scorpions, or horseshoe crabs, can be classified based on their orientation relative to the body axis simplified as either orthognathous (parallel) or labidognathous (inclined), exhibiting considerable diversity across various taxa. Among extinct chelicerates, sea scorpions belonging to the Pterygotidae represent the only chelicerates possessing markedly elongated chelicerae relative to body length. Despite various hypotheses regarding the potential ecological functions and feeding movements of these structures, no comprehensive 3D kinematic investigation has been conducted yet to test these ideas. In this study, we generated a comprehensive 3D model of the pterygotid Acutiramus, making the elongated right chelicera movable by equipping it with virtual joint axes for conducting Range of Motion analyses. Due to the absence in the fossil record of a clear indication of the chelicerae orientation and their potential lateral or ventral movements (vertical or horizontal insertion of joint axis 1), we explored the Range of Motion analyses under four distinct kinematic settings with two orientation modes (euthygnathous, klinogathous) analogous to the terminology of the terrestrial relatives. The most plausible kinematic setting involved euthygnathous chelicerae being folded ventrally over a horizontal joint axis. This configuration positioned the chelicera closest to the oral opening. Concerning the maximum excursion angle, our analysis revealed that the chela could open up to 70°, while it could be retracted against the basal element to a maximum of 145°. The maximum excursion in the proximal joint varied between 55° and 120° based on the insertion and orientation. Our findings underscore the utility of applying 3D kinematics to fossilized arthropods for addressing inquiries on functional ecology such as prey capture and handling, enabling insights into their possible behavioral patterns. Pterygotidae likely captured and processed their prey using the chelicerae, subsequently transporting it to the oral opening with the assistance of other prosomal appendages. [ABSTRACT FROM AUTHOR]

The behavioral avoidance test (BAT) is a well-known diagnostic tool assessing fear by directly measuring avoidance behavior. For instance, in spider phobia, participants or patients gradually approach a live spider until they feel too uncomfortable to continue. However, the use of different BAT protocols in various studies hampers the comparability of results. Moreover, conducting the test requires considerable preparation by researchers and clinicians. Thus, we have developed an open-access online BAT (vBATon). We validated its efficacy in measuring avoidance behavior and eliciting feelings of anxiety and disgust by comparing it to a real-life BAT (rl-BAT). Spider-fearful (N = 31) and nonfearful (N = 31) individuals completed a rl-BAT and vBATon on two separate dates within a 1-week interval. As expected, both tests successfully distinguished between spider-fearful and nonfearful individuals. Crucially, equivalence tests confirmed that vBATon captures avoidance behavior, anxiety, and disgust equal to the rl-BAT. Assessing validity, we found moderate to high correlations between vBATon and (a) the rl-BAT and (b) self-report measurements of spider fear (Spider Phobia Questionnaire, Fear of Spiders Questionnaire). Overall, our study displayed initial evidence of validity of vBATon and suggests that it is a standardized, efficient, and user-friendly alternative to rl-BATs for measuring spider fear. It can be utilized in both research and clinical practice. Public Significance Statement: We developed a software-based, open-access online alternative for the behavioral avoidance for spider fear called vBATon. The test directly measures avoidance behavior by assessing the degree to which an individual can approach a live spider. Our study found that vBATon functions comparably well as the real-life behavioral avoidance test; thus, providing a feasible alternative for researchers and practitioners. [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]

The niche variation hypothesis states that the population niche width expands with increasing interindividual differences in prey utilization (i.e., individual dietary specialization). The main ecological drivers forming this relationship include a) ecological opportunity, b) food limitation and exploitative competition, and c) intraguild interference. Only a limited number of empirical studies have tested the impact of these drivers on the niche variation–width relationship and focused only on vertebrates. Using molecular gut content analysis, we investigated how prey diversity (proxy for ecological opportunity), prey abundance (proxy for exploitative competition / food-limitation), and activity density of guild members (proxy for intraguild interference) affect the short-term individual dietary specialization and consequently the population niche width in local communities of 13 species of predatory beetles and spiders. The study took place in 10 spring barley fields in Sweden in 2011. We found that the niche variation and consequently the average population niche width of the species in the predator community decreased with prey abundance but increased with activity density of guild members. The results indicate that intraguild interference and exploitative competition / food limitation increased dietary variation. The increased diet variation led to the observed population diet expansion. Our results support the niche variation hypothesis and, in contrast to the traditional view, show that negative intraguild interactions may act as a diversifying force. [ABSTRACT FROM AUTHOR]