Groups Of Spiders Research Articles

Phylogenomics of North American cybaeid spiders (Araneae, Cybaeidae), including the description of new taxa from the Klamath Mountains Geomorphic Province

The systematics of humble-in-appearance brown spiders (“marronoids”), within a larger group of spiders with a modified retrolateral tibial apophysis (the RTA Clade), has long vexed arachnologists. Although not yet fully settled, recent phylogenomics has allowed the delimitation and phylogenetic relationships of families within marronoids to come into focus. Understanding relationships within these families still awaits more comprehensive generic-level sampling, as the majority of described marronoid genera remain unsampled for phylogenomic data. Here we conduct such an analysis in the family Cybaeidae Banks, 1892. We greatly increase generic-level sampling, assembling ultraconserved element (UCE) data for 18 of 22 described cybaeid genera, including all North American genera, and rigorously test family monophyly using a comprehensive outgroup taxon sample. We also conduct analyses of traditional Sanger loci, allowing curation of some previously published data. Our UCE phylogenomic results support the monophyly of recognized cybaeids, with strongly supported internal relationships, and evidence for five primary molecular subclades. We hypothesize potential morphological synapomorphies for most of these subclades, bringing a robust phylogenomic underpinning to cybaeid classification. A new cybaeid genus Siskiyugen. nov. and species Siskiyu armillasp. nov. is discovered and described from far northern California and adjacent southern Oregon and a new species in the elusive genus Cybaeozyga, C. furtivasp. nov., is described from far northern California.

Phylogeny of euophryine jumping spiders from ultra‐conserved elements, with evidence on the intersexual coevolution of genitalia (Araneae: Salticidae: Euophryini)

AbstractKnowledge of phylogeny is required to understand the evolution of highly diverse groups such as the euophryine jumping spiders, a lineage showing high species and morphological diversity. In this study, we applied a phylogenomic approach using ultra‐conserved elements (UCE) obtained from 145 taxa to infer the phylogeny of euophryine jumping spiders. The results provide a well‐supported phylogenetic framework for Euophryini, especially for the deeper relationships, in which the monophyly of Euophryini, as well as most clades corresponding to a genus or a group of closely related genera, are strongly supported. Additionally, the evolutionary patterns of male embolus length and female copulatory duct length of 117 euophryine species were investigated through ancestral character state reconstruction and phylogenetically independent contrast analyses using the UCE phylogenetic framework. The results suggest strongly that the evolution of the lengths of male embolus and female copulatory duct in Euophryini is positively correlated. The common ancestor of Euophryini likely had relatively short embolus and copulatory duct, followed by repeated lengthening or shortening of both structures in different lineages. Possible mechanisms that may have caused this intersexual coevolution pattern in Euophryini are discussed. This study advances our understandings of the phylogeny, systematics and genitalic evolution of euophryines, providing a solid foundation for future studies on the diversification and evolution of this jumping spider group.

A chromosome-level genome of the giant vinegaroon Mastigoproctus giganteus exhibits the signature of pre-Silurian whole genome duplication.

Within the arachnids, chromosome-level genome assemblies have greatly accelerated the understanding of gene family evolution and developmental genomics in key groups, such as spiders (Araneae), mites and ticks (Acariformes and Parasitiformes). Among other poorly studied arachnid orders that lack genome assemblies altogether are the clade Pedipalpi, which is comprised of three orders that form the sister group of spiders, which diverged over 400 Mya. We close this gap by generating the first chromosome-level assembly from a single specimen of the vinegaroon Mastigoproctus giganteus (Uropygi). We show that this highly complete genome retains plesiomorphic conditions for many gene families that have undergone lineage-specific derivations within the more diverse spiders. Consistent with the phylogenetic position of Uropygi, macrosynteny in the M. giganteus genome substantiates the signature of an ancient whole genome duplication.

Prey nutrient content is associated with the trophic interactions of spiders and their prey selection under field conditions

Consumers are thought to select food resources based on their nutritional content. While laboratory experiments have explored this, the nutritional dynamics of invertebrate predators have been scarcely studied in the field given various methodological constraints. The intersection of these nutritional dynamics with predator traits is also poorly characterised, leading to many gaps in our understanding of how different predators forage and feed in natural systems. Here, we integrate dietary metabarcoding with prey macronutrient (protein, lipid and carbohydrate) content and abundance to assess how nutrients and predator traits (sex, life stage and taxonomy) interactively drive prey preferences in the field, using spider–prey interactions as a model system. Different spider genera, sexes and life stages had nutritionally distinct diets. Our analyses demonstrated disproportionate foraging (selection and avoidance) for prey rich in different macronutrients, with the nature of these relationships differing between spider taxa, life stages and sexes. This may be explained by niche differentiation among spider groups, driven by biases toward prey rich in different nutrients, or nutrient‐specific foraging in which individual spiders vary their nutritional preferences to redress deficits, although further evidence is required to confirm this. This insight into the nutritional dynamics of generalist invertebrate predators extends our understanding beyond lab‐based behavioural assays and provides a novel framework for other complex real‐world systems.

Hydrological dynamics, wetland morphology and vegetation structure determine riparian arthropod communities in constructed wetlands

Wetland hydrological dynamics often dictate the composition of biological communities found in or near wetlands, either directly or through changes in vegetation composition. However, much remains unknown, particularly regarding how riparian arthropods respond to such dynamics. In this study, we used high-resolution hydrological data, along with presence of grazing livestock and shoreline vegetation height from 41 constructed wetlands in south-western Sweden to explore flood zone areas, flood frequencies, vegetation and grazing as drivers of the resident arthropod communities. The collected material consisted of 26,817 arthropods, where the dominant groups were Diptera (13,258 specimens), spiders (6,207) and Coleoptera (2,858), which were collected using SLAM (Sea Land and Air Malaise) trapping, along with pitfall trapping and vacuum sampling of riparian arthropods. We found group-specific responses to inundation frequencies, where wetlands with higher frequencies had lower abundances of some beetles and tipulids, and where wetlands with longer low-water table periods contained less trichopterans and heteropterans. In contrast, the size of flood zone areas only affected some wolf spider groups, that were more abundant in wetlands with intermediately sized flood zones. Shoreline vegetation height affected multiple groups, spiders, beetles and dipterans, but in different directions, whereas presence of grazing livestock had limited impact on abundances and community compositions. Given the variable responses to wetland hydrological and structural drivers, it seems that wetland arthropod communities would benefit from a high local wetland habitat variability, or wetlandscapes where individual wetlands have differing hydrological dynamics, morphology and vegetation.

Single-cell sequencing suggests a conserved function of Hedgehog-signalling in spider eye development

BackgroundSpiders evolved different types of eyes, a pair of primary eyes that are usually forward pointing, and three pairs of secondary eyes that are typically situated more posterior and lateral on the spider’s head. The best understanding of arthropod eye development comes from the vinegar fly Drosophila melanogaster, the main arthropod model organism, that also evolved different types of eyes, the larval eyes and the ocelli and compound eyes of the imago. The gene regulatory networks that underlie eye development in this species are well investigated revealing a conserved core network, but also show several differences between the different types of eyes. Recent candidate gene approaches identified a number of conserved genes in arthropod eye development, but also revealed crucial differences including the apparent lack of some key factors in some groups of arthropods, including spiders.ResultsHere, we re-analysed our published scRNA sequencing data and found potential key regulators of spider eye development that were previously overlooked. Unlike earlier research on this topic, our new data suggest that Hedgehog (Hh)-signalling is involved in eye development in the spider Parasteatoda tepidariorum. By investigating embryonic gene expression in representatives of all main groups of spiders, we demonstrate that this involvement is conserved in spiders. Additionally, we identified genes that are expressed in the developing eyes of spiders, but that have not been studied in this context before.ConclusionOur data show that single-cell sequencing represents a powerful method to gain deeper insight into gene regulatory networks that underlie the development of lineage-specific organs such as the derived set of eyes in spiders. Overall, we gained deeper insight into spider eye development, as well as the evolution of arthropod visual system formation.

The evolutionary history of Sinopoda spiders (Sparassidae: Heteropodinae): out of the Himalayas and down the mountain slopes

Himalayan orogeny and consequent climatic changes, such as the strengthening of the Asian monsoon, are considered as two main drivers in shaping local biogeography. The mountainous Sinopoda spiders, which are widely distributed in East Asia and Southeast Asia and especially abundant in the mountains near the Himalayas, represent an ideal model lineage for investigating Himalayan biogeography. This is due to their high diversity, limited dispersal ability, and wide elevational distribution, ranging from sea level up to 3500 meters. We investigated the evolutionary history of Sinopoda spiders, focusing on ecological, molecular, and morphological traits in relation to local geological events and fluctuations in Neogene (23.0–2.6 Ma) Asian monsoon patterns. Distribution modeling results show that extant Sinopoda spiders are sensitive to humidity fluctuations. They are mainly distributed in two distinct habitats: areas with moderate precipitation at high altitude (relatively cold) and areas with high precipitation at low altitude (relatively warm). The biogeographical and elevation reconstruction analyses show that as the Himalayas rose and the Asian monsoon intensified, Sinopoda spiders (Sparassidae: Heteropodinae) moved out of the Himalayas (ca 18.1 Ma) then ‘down' the rising mountain slopes (ca 9.6 Ma). We then see a secondary return to the mountains (ca 3.3 Ma) as the severity of the East Asian monsoon decreased. We hypothesize that our ‘out of Himalaya' dispersal pattern hypothesis will also apply to closely related spider groups with limited ballooning ability (e.g. Lycosidae, Thomisidae) or other organisms with low vagility (such as herpetofauna) that are sensitive to humidity and possess similar geographical distributions.

A targeted gene phylogenetic framework to investigate diversification in the highly diverse yet geographically restricted red devil spiders (Araneae, Dysderidae).

The family Dysderidae is a highly diverse group of nocturnal ground-dwelling and active-hunter spiders. Dysderids are mostly restricted to the Western Palearctic, and particularly rich and abundant around the Mediterranean region. Interestingly, the distribution of species richness among its 24 genera and three subfamilies is highly biased-80% of its 644 documented species belong to just two genera, Dysdera (326) and Harpactea (211). Dysderidae provides an excellent study case for evolutionary and ecological research. It includes cases of trophic specialization, which are uncommon among spiders, and exhibit other remarkable biological (e.g. holocentric chromosomes), behavioural (e.g. cryptic female choice), evolutionary (e.g. adaptive radiation) and ecological features (e.g. recurrent colonization of the subterranean environment). The lack of a quantitative hypothesis on its phylogenetic structure has hampered its potential as a testing ground for evolutionary, biogeographical and ecological hypotheses. Here, we present the results of a target, multi-locus phylogenetic analysis, using mitochondrial (cox1, 16s and 12s) and nuclear genes (h3, 28s and 18s), of the most exhaustive taxonomic sample within Dysderidae (104 spp.) to date and across related families (Synspermiata) (83 spp.). We estimate divergence times using a combination of fossil and biogeographic node calibrations and use this timeline to identify shifts in diversification rates. Our results support the monophyly of the Dysderidae subfamilies Rhodinae and Dysderinae but reject Harpacteinae as currently defined. Moreover, the clades recovered within Harpacteinae do not support its current taxonomy. The origin of the family most likely post-dated the break-up of Pangea, and cave colonization may be older than previously considered. After correcting for the taxonomic artefacts, we identified a significant shift in diversification rates at the base of the genus Dysdera. Although the unique coexistence of specialist and generalist diets within the lineage could be suggested as the potential driver for the rate acceleration, further quantitative analyses would be necessary to test this hypothesis.

Integrative species delimitation and five new species of lynx spiders (Araneae, Oxyopidae) in Taiwan.

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 cordivulva sp. nov., Hamat. leporauris sp. nov., Tapponia auriola sp. nov., T. parva sp. nov. and T. rarobulbus sp. 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. cordivulva sp. nov. and Hamat. foveata showed shallow genetic differentiation in the COI, but they were unequivocally distinguishable according to their genitalia. In contrast, T. parva sp. 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.

Study of the Bionomy and the Therapeutic Potential of a Substance Obtained from Spider Venom (Arthropoda: Araneae)

Venom is present in most spiders in the world, only two groups of venomous spiders are known and their chemical composition varies greatly between species. The vast majority have venom that is not very toxic to the human body, as is the case with crabs. However, the venom of other spiders affects humans more seriously. This manuscript aims to verify the bionomics of spiders and their therapeutic potential (Arthropoda: Araneae). Regarding the type of research source, As for the type of research source, it was worked with scientific articles published in national and international magazines. This type of production is commonly the most valued in all bibliographic production and is the easiest to access. Access to articles was through virtual libraries such as SciELO, the University of São Paulo, Latin American Literature, and the University of Brasília. This library has a specific section for Hymenoptera, with journals and article texts available in full. Considering only this section constitutes a limitation of the study since articles belonging to journals that are part of other sections of the electronic library could also contribute to the discussion of the production of knowledge. However, in principle, within these articles, there could not necessarily be a discussion focused on biology, ecology, and taxonomy.

Multilocus genetic and morphological phylogenetic analysis: Unveiling a new genus and species in the Tribe Nannenini of jumping spiders (Araneae, Salticidae)

AbstractJumping spiders (Salticidae) are a diverse group of non‐web‐building predators and the most species‐rich spider family. The Salticidae Tribe Nannenini consists of a small group of Oriental jumping spiders that are very poorly known. The use of explicit phylogenetic analyses to establish its affinities has so far remained limited. The Nannenini genus Epidelaxia has a peculiar morphology, making its systematic position uncertain. In this study, we present a comprehensive dataset combining molecular and morphological data for Nannenini, including exemplars from all genera. This dataset comprises DNA sequences of approximately 2400 bp, including nuclear genes (18S, 28S and H3) and the mitochondrial gene CO1, sequenced for 40 taxa (20 ingroups and 20 outgroups), along with 61 morphological characters. Notably, both DNA sequences and morphological traits were analysed separately and concurrently for the first time. The Nannenini clade is recovered with high support. Further, Epidelaxia is monophyletic and sister to Tubalaxia gen. n. This is the first hypothesis on the internal phylogenetic structure of Epidelaxia and its placement within the Tribe Nannenini. A new genus Tubalaxia gen. n. and the following new species are described: E. bharathi sp. n., E. somasundaram sp. n., T. castanea sp. n., T. aurea sp. n. The following new combination is proposed: Tubalaxia minuta (Prószyński, 1992) comb. n. Epidelaxia albostellata, E. albocruciata and E. obscura are redescribed. It is worth noting that the newly described species face endangerment due to their limited distribution and small population sizes.

A Novel Spider Monkey Optimization for Reliable Data Dissemination in VANETs Based on Machine Learning.

The growth in linked and autonomous vehicles has led to the emergence of vehicular ad hoc networks (VANETs) as a means to enhance road safety, traffic efficiency, and passenger comfort. However, VANETs face challenges in facilitating trustworthiness and high-quality services due to communication delays caused by traffic, dynamic topology changes, variable speeds, and other influencing factors. Hence, there is a need for a reliable data dissemination scheme capable of reducing communication delays among hops by identifying effective forwarder nodes. In this paper, we propose a novel, weighted, estimated, spider monkey-based, nature-inspired optimization (w-SMNO) method to generate a set of efficient relays. Additionally, we introduce a dynamic weight assignment and configuration model to enhance system accuracy using a neural network based on backpropagation with gradient descent optimization techniques to minimize errors in the machine learning model. The w-SMNO also incorporates a distinct algorithm for effective relay selection among multiple monkey spider groups. The simulation results demonstrate substantial improvements in w-SMNO, with a 35.7% increase in coverage, a 41.2% reduction in the end-to-end delay, a 36.4% improvement in the message delivery rate, and a 38.4% decrease in the collision rate compared to the state-of-the-art approaches.

Should I stay or should I fly: Aerial dispersal in a funnel‐web wolf spider from the grasslands of southern South America

AbstractBallooning is a mechanism of aerial dispersal present in some groups of spiders. By releasing silken threads that are blown by the wind, spiders can travel long distances through the air. Aglaoctenus lagotis is a wolf spider that lives its entire life associated with a funnel‐web, despite the wandering habit that characterizes species in this family. We can find two forms of the species in Uruguay, one of them a strict inhabitant of grasslands of Uruguay. The high habitat specificity and the spiderlings observed surrounding the maternal web suggest a low aerial dispersal capacity in this species. In this study, we tested whether A. lagotis spiderlings are capable of dispersing by ballooning. We conducted laboratory and field experiments during the day and night, to record the occurrence of ballooning and typical behaviours that precede ballooning. We recorded ballooning both in the laboratory and in the field, and it was more frequent during the day. Although it has been reported repeatedly in species from this family, we never observed the pre‐ballooning tip‐toeing behaviour in A. lagotis. Ballooning was preceded by dropping on dragline, considered a behaviour that could generate aerial dispersion of lesser distance than that generated by the tip‐toeing. In this paper, we shall discuss the implications of this form of aerial dispersal, considering that the species analysed is a web wolf spider.

Clinical Study on Spider Groups of Drugs with Special Emphasis on Tarentula through the Cases Epileptic Convulsion

I worked on patients suffering from Epileptic convulsion with age between 2 years to 10 years as inclusion criteria in the cases. It was observed through comparative study which verified the importance of keeping these symptoms. Patients were relieved to great extent by the medicines which are obtained by the totality of symptoms. Epileptic convulsion is the disorder characterised by a staring spell, uncontrollable jerking movement of the arms and legs, loss of consciousness or awareness, fatigue, body ache, Persistent EPILEPSY, weight loss, discomfort feeling, weakness & temporary confusion. Psychic symptoms such as fear, anxiety. Homoeopathic constitutional treatment based on the individual case is the most suitable treatment and would aim to heal the underlying physical crisis causing the Epileptic convulsion. The remedies work by stimulating the body’s natural ability to heal itself, acting as a catalyst for healing. Homeopathy can be of assistance in retrieving normal health and treating any other physical issues and sequel related to Epileptic convulsion. Homoeopathic medicines can also prevent relapse of Epileptic convulsion. Methods: Randomised controlled trial study design has been adopted to know the efficacy of homoeopathic treatment in cases of Epileptic convulsion and its complication. A total number of 30 patients, showing features of uncontrollable jerking movement of the arms and legs body ache, low grade EPILEPSY, discomfort, temporary confusion& weakness were selected who were fulfilling the inclusion and exclusion criteria. Follow up has been taken for two months with at least six visits. From guardian of every subject, a written informed consent has been taken.

A trade-off in evolution: the adaptive landscape of spiders without venom glands.

Venom glands play a key role in the predation and defense strategies of almost all spider groups. However, the spider family Uloboridae lacks venom glands and has evolved an adaptive strategy: they excessively wrap their prey directly with spider silk instead of paralyzing it first with toxins. This shift in survival strategy is very fascinating, but the genetic underpinnings behind it are poorly understood. Spanning multiple spider groups, we conducted multiomics analyses on Octonoba sinensis and described the adaptive evolution of the Uloboridae family at the genome level. We observed the coding genes of myosin and twitchin in muscles are under positive selection, energy metabolism functions are enhanced, and gene families related to tracheal development and tissue mechanical strength are expanded or emerged, all of which are related to the unique anatomical structure and predatory behavior of spiders in the family Uloboridae. In addition, we also scanned the elements that are absent or under relaxed purifying selection, as well as toxin gene homologs in the genomes of 2 species in this family. The results show that the absence of regions and regions under relaxed selection in these spiders' genomes are concentrated in areas related to development and neurosystem. The search for toxin homologs reveals possible gene function shift between toxins and nontoxins and confirms that there are no reliable toxin genes in the genome of this group. This study demonstrates the trade-off between different predation strategies in spiders, using either chemical or physical strategy, and provides insights into the possible mechanism underlying this trade-off. Venomless spiders need to mobilize multiple developmental and metabolic pathways related to motor function and limb mechanical strength to cover the decline in adaptability caused by the absence of venom glands.

All about being old and shooting hairs: clade age and urticating hair explain the patterns of diversification in tarantulas.

The extreme asymmetry of species richness distribution across the tree of life has always intrigued evolutionary biologists. Two competing explanations have been proposed to explain this pattern-the clade age hypothesis and diversification rate variation. While these two scenarios may not be mutually exclusive, to what extent time and diversification rates interact to explain species richness patterns remains understudied. Here, we investigate the relative influence of these two scenarios using tarantulas (Family: Theraphosidae) as a model. Tarantulas represent a speciose group of spiders found worldwide but exceptionally diverse in South America. These spiders show two distinct patterns of microhabitat use (ground-dwelling or arboreal) and defense strategies (presence or absence of urticating hairs). Using various trait-independent and dependent diversification models, we test the clade age hypothesis, the role of microhabitat, antipredator defense strategy, and geography in influencing diversification rates. Our results suggest that clade age is the primary predictor of species richness distribution across the tarantula subfamilies. However, the presence of urticating hair probably disrupted this pattern in some clades by increasing the net diversification rates, not by increasing the speciation rate but by reducing the extinction rate.

Effects of heterogeneity on the ecological diversity and redundancy of forest fauna

Heterogeneity in forests might promote biodiversity not only through an increase in niche volume but also through other processes, such as an increase in resources and their spatial distribution. However, negative relationships between heterogeneity and biodiversity have also been observed, which may indicate that heterogeneity acts as a filter for some species. This study examined the effects of different facets of heterogeneity in forest stands, i.e. deadwood, plant diversity, forest stand structure, and micro-scale topography, on the ecological (functional-phylogenetic) diversity and redundancy of nine animal groups: moths, true bugs, different functional groups of beetles, spiders, birds, and bats. Overall, we found positive effects of heterogeneity on ecological diversity and redundancy. Although the effect of heterogeneity at the local scale was moderate compared with the general effect of region, greater heterogeneity could be beneficial to some species groups and lead to more resilient species communities.

Cephalopod versus vertebrate eyes

Vertebrates and cephalopods are the two major animal groups that view the world through sophisticated camera-type eyes. There are of course exceptions: nautiloid cephalopods have more simply built pinhole eyes. Excellent camera type eyes are also found in other animals, such as some spider groups, a few snails, and certain marine worms, but the vast majority of large camera-type eyes belong to cephalopods and vertebrates. Vertebrates and cephalopods also devote major parts of their brains to the processing of visual information. Obviously, there are differences in eye performance among cephalopods and vertebrates, but there are no major subgroups where vision seems to have low priority. The similarity in eye geometry is striking, especially between fish and coleoid cephalopods, with a hemispherical retina centred around a spherical lens. Do these similarities mean that vertebrate and cephalopod eyes are equally good? Comparing the eyes of vertebrates and cephalopods reveals many fundamental differences with surprisingly small consequences for vision, but also one difference that means that cephalopods and vertebrates do not share the same visual world.

Copulatory mechanics of ghost spiders reveals a new self-bracing mechanism in entelegyne spiders.

Spiders evolved a distinctive sperm transfer system, with the male copulatory organs located on the tarsus of the pedipalps. In entelegyne spiders, these organs are usually very complex and consist of various sclerites that not only allow the transfer of the sperm themselves but also provide a mechanical interlock between the male and female genitalia. This interlocking can also involve elements that are not part of the copulatory organ such as the retrolateral tibial apophysis (RTA)-a characteristic of the most diverse group of spiders (RTA clade). The RTA is frequently used for primary locking i.e., the first mechanical engagement between male and female genitalia. Despite its functional importance, some diverse spider lineages have lost the RTA, but evolved an apophysis on the femur instead. It can be hypothesized that this femoral apophysis is a functional surrogate of the RTA during primary locking or possibly serves another function, such as self-bracing, which involves mechanical interaction between male genital structures themselves to stabilize the inserted pedipalp. We tested these hypotheses using ghost spiders of the genus Josa (Anyphaenidae). Our micro-computed tomography data of cryofixed mating pairs show that the primary locking occurs through elements of the copulatory organ itself and that the femoral apophysis does not contact the female genitalia, but hooks to a projection of the copulatory bulb, representing a newly documented self-bracing mechanism for entelegyne spiders. Additionally, we show that the femoral self-bracing apophysis is rather uniform within the genus Josa. This is in contrast to the male genital structures that interact with the female, indicating that the male genital structures of Josa are subject to different selective regimes.

Trophic interactions between plants, pollinators, florivores and predators: a global systematic review

Abstract The multitrophic relationships between plants, pollinators, florivores and spiders that predate floral visitors influence plant reproductive success, and some plant characteristics influence the choices of these animals. The aim of this study was to integrate the global data on these multitrophic relationships and answer the following questions. How are the studies distributed by biomes? What are the groups of plants, pollinators, florivores, spiders and prey recorded? What plant features explain the presence of florivores and spiders? What is the effect of spiders on fruit set? A systematic literature review was carried out to extract the necessary information. The most frequently observed families of plants, pollinators, florivores, spiders and prey were, respectively, herbaceous Asteraceae, Apidae (bees), Chrysomelidae (beetles), Thomisidae (spiders) and Bombyliidae (flies). The choice of flowers by florivores was explained by floral longevity. The choice of flowers by spiders was explained by life-form, symmetry, shape, pollination unit (more frequent in isolated flowers than in inflorescences) and resource (nectar). Spiders had a neutral general effect on fruit set, indicating that the study scale influenced the result. An important knowledge gap concerns the influence of florivores on fruit set. Studies that follow standardized methodologies are necessary.