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Intensive agriculture has profoundly altered biodiversity and trophic relationships in agricultural landscapes, leading to the deterioration of many ecosystem services such as pollination or biological control. Information on which spatio-temporal factors are simultaneously affecting crop pests and their natural enemies is required to improve conservation biological control practices. We conducted a study in 80 winter wheat crop fields distributed in three regions of North-western Europe (Brittany, Hauts-de-France and Wallonia), along intra-regional gradients of landscape complexity. Five taxa of major crop pests (aphids and slugs) and natural enemies (spiders, carabids, and parasitoids) were sampled three times a year, for two consecutive years. We analysed the influence of regional (meteorology), landscape (structure in both the years n and n-1) and local factors (hedge or grass strip field boundaries, and distance to boundary) on the abundance and species richness of crop-dwelling organisms, as proxies of the service/disservice they provide. Firstly, there was higher biocontrol potential in areas with mild winter climatic conditions. Secondly, natural enemy communities were less diverse and had lower abundances in landscapes with high crop and wooded continuities (sum of interconnected crop or wood surfaces), contrary to slugs and aphids. Finally, field boundaries with grass strips were more favourable to spiders and carabids than boundaries formed by hedges, while the opposite was found for crop pests, with the latter being less abundant towards the centre of the fields. We also revealed temporal modulation-and sometimes reversion-of the impact of local elements on crop biodiversity. To some extent, these results cause controversy because they show that hedgerows and woodlots should not be the unique cornerstones of agro-ecological landscape design strategies. We point out that combining woody and grassy habitats to take full advantage of the features and ecosystem services they both provide (biological pest control, windbreak effect, soil stabilization) may promote sustainable agricultural ecosystems. It may be possible to both reduce pest pressure and promote natural enemies by accounting for taxa-specific antagonistic responses to multi-scale environmental characteristics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Mass media plays an important role in the construction and circulation of risk perception associated with animals. Widely feared groups such as spiders frequently end up in the spotlight of traditional and social media. We compiled an expert-curated global database on the online newspaper coverage of human-spider encounters over the past ten years (2010-2020). This database includes information about the location of each human-spider encounter reported in the news article and a quantitative characterisation of the content-location, presence of photographs of spiders and bites, number and type of errors, consultation of experts, and a subjective assessment of sensationalism. In total, we collected 5348 unique news articles from 81 countries in 40 languages. The database refers to 211 identified and unidentified spider species and 2644 unique human-spider encounters (1121 bites and 147 as deadly bites). To facilitate data reuse, we explain the main caveats that need to be made when analysing this database and discuss research ideas and questions that can be explored with it., (© 2022. The Author(s).)

Spiders are a highly diversified group of arthropods and play an important role in terrestrial ecosystems as ubiquitous predators, which makes them a suitable group to test a variety of eco-evolutionary hypotheses. For this purpose, knowledge of a diverse range of species traits is required. Until now, data on spider traits have been scattered across thousands of publications produced for over two centuries and written in diverse languages. To facilitate access to such data, we developed an online database for archiving and accessing spider traits at a global scale. The database has been designed to accommodate a great variety of traits (e.g. ecological, behavioural and morphological) measured at individual, species or higher taxonomic levels. Records are accompanied by extensive metadata (e.g. location and method). The database is curated by an expert team, regularly updated and open to any user. A future goal of the growing database is to include all published and unpublished data on spider traits provided by experts worldwide and to facilitate broad cross-taxon assays in functional ecology and comparative biology. Database URL:https://spidertraits.sci.muni.cz/., (© The Author(s) 2021. Published by Oxford University Press.)

Although functional and phylogenetic diversities are increasingly used in ecology for a variety of purposes, their relationship remains unclear, and this relationship likely differs among taxa, yet most recent studies focused on plants. We hypothesize that communities may be diverse in functional traits due to presence of: many phylogenetic lineages, trait divergence within lineages, many species and random functional variation among species, weak filtering of traits in favorable environments, or strong trait divergence in unfavorable environments. We tested these predictions for taxa showing higher (ants), or lower (spiders, ground beetles) degrees of competition and niche construction, both of which might decouple functional traits from phylogenetic position or from the environment. Studying > 11,000 individuals and 216 species from coastal heathlands, we estimated functional as minimum spanning trees using traits related to the morphology, feeding habits and dispersal, respectively. Relationships between functional and phylogenetic diversities were overall positive and strong. In ants, this relationship disappeared after accounting for taxonomic diversities and environments, whereas in beetles and spiders taxonomic diversity is related to functional diversity only via increasing phylogenetic diversity. Environmental constraints reduced functional diversity in ants, but affected functional diversity only indirectly via phylogenetic diversity (ground beetles) and taxonomic and then phylogenetic diversity (spiders and ground beetles). Results are consistent with phylogenetic conservatism in traits in spiders and ground beetles. In ants, in contrast, traits appear more phylogenetically neutral with any new species potentially representing a new trait state, tentatively suggesting that competition or niche construction might decouple phylogenetics from trait diversity., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Although species delimitation is often controversial, emerging DNA-based and classical morphology-based methods are rarely compared using large-scale samplings, even less in the case of widely distributed species that have distant, allopatric populations. In the current study, we examined species boundaries within two wolf spider species of the genus Pardosa (Araneae, Lycosidae), P. riparia and P. palustris. Wolf spiders constitute an excellent model for testing the relevance of traditional vs. modern methods in species and population delimitation because several closely related species are distributed over cross-continental geographic ranges. Allopatric populations of the two Pardosa species were sampled across Europe to Far East Russia (latitudinal range > 150°) and several dozen individuals were studied using morphological characters (morphometry of three measures for both sexes, plus five in males only and two in females only), DNA barcoding (COI sequencing) and double-digest restriction site associated DNA sequencing (ddRADseq). The results obtained allow for changing the taxonomic status of two Far East Russian populations to subspecies and ddRADseq proved to be a powerful tool for taxonomic research despite scarce sampling and inherent subjectivity of species delimitation in allopatry. Overall, this study pleads for both multi-criteria and more population-based studies in taxonomy.

Fishing spiders (Dolomedes spp.) make an interesting model to predict the impact of global changes because they are generalist, opportunistic predators, whose distribution is driven mostly by abiotic factors. Yet, the two European species are expected to react differently to forthcoming environmental changes, because of habitat specialization and initial range. We used an original combination of habitat and dispersal data to revisit these predictions under various climatic scenarios. We used the future range of suitable habitat, predicted with habitat variables only, as a base layer to further predict the range or reachable habitat by accounting for both dispersal ability and landscape connectivity. Our results confirm the northward shift in range and indicate that the area of co-occurrences should also increase. However, reachable habitat should expand less than suitable habitat, especially when accounting for landscape connectivity. In addition, the potential range expansion was further limited for the red-listed D. plantarius, which is more of a habitat specialist and has a lower ability to disperse. This study highlights the importance of looking beyond habitat variables to produce more accurate predictions for the future of arthropods populations.

While Liocranidae is a family encompassing 283 species distributed in 32 genera (World Spider Catalog 2019), the genus Agraecina Simon, 1932 currently counts only six described species: Agraecina canariensis Wunderlich, 1992 from the Canaries, A. cristriani (Georgescu, 1989) from Romania, A. hodna Bosmans, 1999 from Algeria, A. lineata (Simon, 1878) from Europe and Kazakhstan, A. rutilia (Simon, 1897) from Sierrra Leone, and A. scupiensis Deltshev, 2016 from Macedonia. During an ecological survey in the north of Tunisia, a new Agraecina species was discovered and is described here. Spiders were collected using pitfall traps in a salt marsh.

Many arachnids like other terrestrial arthropods, provide extensive maternal care. Few studies have quantified the underlying physiological costs of maternal care. We investigated how maternal care affects the free-moving wolf spider's (Pardosa saltans) energy requirements. We described in detail their basic reproduction biology (i.e. carrying cocoon and young) and we evaluated the variation in the females' energy reserves during maternal care. Our results show that mothers guard eggs until hatching and then guard their spiderlings for 27-30 more days. Laboratory observations indicated that spiderlings start leaving the maternal abdomen gradually 5-7days after hatching. Females carry an egg sac (cocoon) that can weigh up to 77% of their post-reproduction weight and carry young that weigh 87-100% of their body mass. Females lost weight over time despite regular food intake, while carrying cocoon and young; but their weights increased gradually during the dispersal of young. The contributions of proteins, glucose and triglycerides to maintain females' energy were calculated. Their energetic state varied during maternal care, in particular lipid levels declined, during the care of spiderlings when the females' predatory behaviour was inhibited. Our results show that the maternal care provided by P. saltans females is particularly costly physiologically, during the 30days following egg sac formation and development of spiderlings, even when food is available., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Spiders are known to commonly use aerial dispersal, so-called ballooning, especially at juvenile stages. They produce a silk thread that allows them to rise up in the air to disperse, which serves as inbreeding avoidance or to find an optimal over-winter habitat. Studies of phenology, species and meteorological factors associated with aerial dispersal have been limited to laboratory settings, with few data obtained under natural settings and no studies to date executed in France. To understand aerial dispersal, we conducted daily sampling between 2000 and 2002 at a height of 12m. For adults, high proportions of "ballooners" were observed during four seasonal peaks, with dispersal most prevalent during summer, while for juveniles dispersal was protracted across summer and fall. Linyphiidae is the most abundant family among the 10,879 individuals caught. We show a significant and negative influence of high wind speeds on ballooning, an effect that increased even under low temperatures (<19°C). At wind speeds greater than 4m·s(-1) dispersal becomes difficult, and is almost impossible beyond 5.5m·s(-1). Ballooning ability is reported for the first time for several species. This study increases our knowledge on aerial dispersal in spiders in an agricultural context. Such behaviour can be seen as a survival strategy to escape from a disturbed and unstable landscape., (Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.)

Soil salinity and the salinity of trophic resources may alter the osmoregulatory processes of arthropod, challenging the smooth regulation of body water, and, ultimately, survival. The intra and extracellular build-up of osmolytes represent a common strategy to attenuate acute hyperosmotic stress in several arthropod species. In the present study, we aimed to determine the impact of substrate and trophic resource salinities on salt tolerance in the female wolf spider, Arctosa fulvolineata, which is considered a specialist salt marsh species. We evaluated adult female survival and egg laying, and quantified the osmo-induced accumulation of compatible solutes (GC-MS). Three concentrations of substrate salinity were tested (0‰, 35‰ and 70‰) under three trophic conditions (starved spiders, spiders fed with salt prey [intertidal amphipods] and spiders fed with unsalted prey [freshwater amphipods]). We found no support for diet preferences in female A. fulvolineata, which exhibited similar predation rates on freshwater and marine amphipods. Survival and egg-laying were significantly impaired when female A. fulvolineata were exposed to hypersaline conditions for 12 days. Our results showed an increase in the level of several compatible solutes when spiders were exposed for 12 days to saline conditions. For instance, α-alanine, β-alanine, arginine, asparagine, aspartate, homoserine, glutamine, glycine, proline and serine levels were 4-10 times higher under hypersaline conditions. The osmo-induced accumulation of amino acids may increase the osmolality of body fluids, thus enhancing the smooth regulation of body fluids and survival ability of wolf spider under extreme saline conditions., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Current models in evolutionary ecology predict life history alterations in response to habitat suitability to optimize fitness. Only few empirical studies have demonstrated how life history traits that are expected to trade off against each other differ among environments. In Europe, many salt marshes have been recently invaded by the grass Elymus athericus. Previous studies however showed higher densities of the endangered spider Arctosa fulvolineata (Araneae: Lycosidae) in invaded salt marshes compared to natural habitats, which suggests a lower habitat suitability in the latter. The aim of this study was to determine if this emerging habitat (1) affects the amount of resource acquisition and (2) alters the balance between life history traits that are expected to trade off against each other in this stenotopic salt marsh species. As suggested by theoretical studies, an optimization of fitness by increasing egg size at the cost of decreasing fecundity in unsuitable (i.e., natural) habitats was expected. Females presenting cocoon were then collected in close invaded and natural salt marsh areas within the Mont Saint-Michel Bay (France). By considering female mass as covariate, cocoon mass, number of eggs, and egg volume were compared between both habitats. Clutch mass was strongly determined by female mass in both habitats. Clutch mass was however significantly smaller in the natural habitat compared to the invaded habitat, indicating a higher resource acquisition in the latter. When correcting for female size, fecundity was additionally increased in the invaded habitat through a significant decrease in egg size. This phenotypic response can be explained by differences in habitat structure between invaded and natural habitats: the former offers a more complex litter favoring nocturnal wanderers like A. fulvolineata. The existence of such an adaptive reproduction strategy depending on habitat suitability constitutes an original case of an invasion that favors an endangered species.

Spiders constitute a major arthropod group in regularly inundated habitats. Some species survive a flooding period under water. We compared survival during both submersion and a recovery period after submersion, in three stenotopic lycosids: two salt-marsh species Arctosa fulvolineata and Pardosa purbeckensis, and a forest spider Pardosa lugubris. Both activity and survival rates were determined under controlled laboratory conditions by individually surveying 120 females kept submerged in sea water. We found significant differences between the three species, with the two salt-marsh spiders exhibiting higher survival abilities. To our knowledge, this study reports for the first time the existence of a hypoxic coma caused by submersion, which is most pronounced in A. fulvolineata, the salt-marsh spider known to overcome tidal inundation under water. Its ability to fall into that coma can therefore be considered a physiological adaptation to its regularly inundated habitat.

Tropical rainforests are one of the most diverse ecosystems worldwide, yet the mechanisms driving the spatial distribution of their biodiversity remain poorly understood. Here, we tested the effects of elevation, sampling method and their interaction on α and β diversities of spider assemblages between two close elevations in one tropical forest of French Guiana. Through a standardized protocol, both ground- and vegetation-dwelling (up to 2.5-m high) assemblages were sampled at medium and high elevations, during day and night using 3 complementary methods (beating, sweeping, and nocturnal hand collecting). Despite a lower total number of species at high elevation, we found no significant effect of elevation on mean species richness. However, elevation had a significant effect on species composition, notably with less web builders and more ground hunters at higher elevations. In addition, we found a significant effect of sampling methods on both estimated species richness and composition. These results suggest that even slight elevation shape spider assemblages of tropical forests, which probably contributes to the high turn-over and amazing gamma diversity of these ecosystems. [ABSTRACT FROM AUTHOR]

In the past decade, environmental DNA (eDNA) assays have become an essential tool to investigate species presence with samples from the environment instead of collected specimens. eDNA sampling techniques have proved their worth in freshwater and marine studies; now, some trends emerge for their use in terrestrial habitats and particularly to study arthropods. After a systematic review of the literature, we illustrate and analyse the diversity of such studies and discuss their benefits and drawbacks.We identified the most relevant research themes and focused on (i) the taxa and environmental sample types targeted and (ii) the details of the survey scheme. In parallel, we also assessed the available number of sequences from cytochrome c oxidase subunit I (COI), 16S and 18S barcode regions for four major taxa (spiders, centipedes, springtails and insects) in relation to their diversity.We found strong taxonomic and geographic biases regarding coverage per barcode. eDNA research on terrestrial arthropods mainly focuses on insect species that affect humanity in a positive or negative way, and the availability of sequences is much higher for species from temperate‐developed countries than from tropical ones. Moreover, although a high variety of environmental samples are being used, most studies do not assess the barcode completeness of the target taxa nor compare the efficacy of eDNA monitoring technique to other well established and known traditional techniques.Careful workflow designs and comparisons are needed before giving any management or conservation advice as eDNA monitoring does not come without error. Strengths and weaknesses of eDNA assays for conservation are discussed. [ABSTRACT FROM AUTHOR]

Copyright of Entomologia Experimentalis et Applicata is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Patterns of phototaxis are incompletely characterized in arachnids and hardly generalizable because of large variations in orders, families, species, environments, and methods employed. In a neotropical forest of French Guiana, we tested the effect of both light and diameter on pitfall trap catches. Light had a significant effect on capture rates of all arachnids and on Araneae alone, with more individuals caught in lit traps. Without light, pitfall diameter had no effect on capture rates, while in lit traps, significantly fewer individuals were captured only in smaller traps. Light trapping is thus a promising tool to complete inventories in tropical forests. This field experiment calls for further studies of the mechanisms by which arachnids are attracted by light, especially by unraveling an actual phototaxis from indirect effects like prey attraction. [ABSTRACT FROM AUTHOR]

There is a secret pleasure in naming new species. Besides traditional etymologies recalling the sampling locality, habitat or morphology of the species, names may be tributes to some meaningful person, pop culture references and even exercises of enigmatography. Using a dataset of 48 464 spider etymologies, we tested the hypothesis that species names given by taxonomists are deeply influenced by their cultural background. Specifically, we asked whether naming practices change through space or have changed through time. In absolute terms, etymologies referring to morphology were the most frequently used. In relative terms, references to morphology peaked in 1850–1900 and then began to decline, with a parallel increase in etymologies dedicated to people and geography. We also observed a dramatic increase in etymologies referring to pop culture and other cultural aspects in 2000–2020, especially in Europe and the Americas. While such fashionable names often carry no biological information regarding the species itself, they help give visibility to taxonomy, a discipline currently facing a profound crisis in academia. Taxonomy is among the most unchanged disciplines across the last centuries in terms of tools, rules and writing style. Yet, our analysis suggests that taxonomists remain deeply influenced by their living time and space. [ABSTRACT FROM AUTHOR]

Dispersal and its evolution play a key role for population persistence in fragmented landscapes where habitat loss and fragmentation increase the cost of between-habitat movements. In such contexts, it is important to know how variation in dispersal and other traits is structured, and whether responses to landscape fragmentation are aligned with underlying dispersal-trait correlations, or dispersal syndromes. We, therefore, studied trait variation in Erigone longipalpis , a European spider species specialist of (often patchy) salt marshes. We collected spiders in two salt-marsh landscapes differing in habitat availability. We then reared lab-born spiders for two generations in controlled conditions, and measured dispersal and its association with various key traits. Erigone longipalpis population densities were lower in the more fragmented landscape. Despite this, we found no evidence of differences in dispersal, or any other trait we studied, between the two landscapes. While a dispersal syndrome was present at the among-individual level (dispersers were more fecund and faster growing, among others), there was no indication it was genetically driven: among-family differences in dispersal were not correlated with differences in other traits. Instead, we showed that the observed phenotypic covariations were mostly due to within-family correlations. We hypothesize that the dispersal syndrome is the result of asymmetric food access among siblings, leading to variation in development rates and carrying over to adult traits. Our results show we need to better understand the sources of dispersal variation and syndromes, especially when dispersal may evolve rapidly in response to environmental change. [ABSTRACT FROM AUTHOR]

Dispersal abilities are important to support metapopulation functioning and species distributions, yet it is rarely accounted for in conservation. Here, we compared the propensity for dispersal between the two fishing spiders present in Europe: the widespread habitat‐generalist Dolomedes fimbriatus and the scarcer red‐listed Dolomedes plantarius.We experimentally tested for airborne and waterborne dispersal using first instar juveniles sampled in nursery webs, and older juveniles. We estimated the propensity for short and long‐distance dispersal of airborne and waterborne behaviours, and we tested the difference between species with generalised linear mixed models.Airborne (ballooning) and waterborne (sailing) behaviours were more frequent for D. fimbriatus than for D. plantarius, indicating a higher propensity of the former for long‐distance dispersal.The frequency of rappelling behaviour, and thus the propensity for short‐distance dispersal, did not differ between species. However, we found contrasting results for short‐distance dispersal on the water, with rowing being more frequent and running less frequent for D. plantarius than for D. fimbriatus.The different propensity for dispersal between the two species might be partly explained by the ecology of D. plantarius, which is known to be more habitat‐specialist and more dependent to water bodies than D. fimbriatus.The limited propensity for dispersal of the red‐listed D. plantarius is another argument for conserving an interconnected network of wetlands in Fennoscandia. Indeed, increased isolation of populations would be detrimental for species maintenance. [ABSTRACT FROM AUTHOR]

Large quantities of Pacific oyster and blue mussel shells are deposited along the shore of Mont-Saint-Michel Bay in western France as waste from aquaculture operations. These shell beds have become integrated into the salt marsh vegetation over time and provide a habitat for an endangered wolf spider species. The spiders use the shells as a refuge and breeding habitat, hiding during the day and hunting at night. While the importance of anthropogenic resource subsidies for predatory spiders is known, documented examples in the scientific literature are rare. [Extracted from the article]

Most species encounter large variations in abiotic conditions along their distribution range. The physiological responses of most terrestrial ectotherms (such as insects and spiders) to clinal gradients of climate, and in particular gradients of temperature, can be the product of both phenotypic plasticity and local adaptation. This study aimed to determine how the biogeographic position of populations and the body size of individuals set the limits of cold (freezing) resistance of Dolomedes fimbriatus. We compared D. fimbriatus to its sister species Dolomedes plantarius under harsher climatic conditions in their distribution range. Using an ad hoc design, we sampled individuals from four populations of Dolomedes fimbriatus originating from contrasting climatic areas (temperate and continental climate) and one population of the sister species D. plantarius from continental climate, and compared their supercooling ability as an indicator of cold resistance. Results for D. fimbriatus indicated that spiders from northern (continental) populations had higher cold resistance than spiders from southern (temperate) populations. Larger spiders had a lower supercooling ability in northern populations. The red‐listed and rarest D. plantarius was slightly less cold tolerant than the more common D. fimbriatus, and this might be of importance in a context of climate change that could imply colder overwintering habitats in the north due to reduced snow cover protection. The lowest cold resistance might put D. plantarius at risk of extinction in the future, and this should be considered in conservation plan. [ABSTRACT FROM AUTHOR]

High diversity in tropical compared to temperate regions has long intrigued ecologists, especially for highly speciose taxa like terrestrial arthropods in tropical rainforests. Previous studies showed that arthropod herbivores account for much tropical diversity, yet differences in the diversity of predatory arthropods between tropical and temperate systems have not been properly quantified. Here, we present the first standardized tropical–temperate forest quantification of spider diversities, a dominant and mega‐diverse taxon of generalist predators. Spider assemblages were collected using a spatially replicated protocol including two standardized sampling methods (vegetation sweep netting and beating). Fieldwork took place between 2010 and 2015 in metropolitan (Brittany) and overseas (French Guiana) French territories. We found no significant difference in functional diversity based on hunting guilds between temperate and tropical forests, while species richness was 13–82 times higher in tropical versus temperate forests. Evenness was also higher, with tropical assemblages up to 55 times more even than assemblages in temperate forests. These differences in diversity far surpass previous estimates and exceed tropical–temperate ratios for herbivorous taxa. [ABSTRACT FROM AUTHOR]

We assessed how assemblages of spiders were structured in small Hawaiian tropical forest fragments (Hawaiian, kipuka) within a matrix of previous lava flows, over both space (sampling kipuka of different sizes) and time (comparison with a similar study from 1998). Standardized hand-collection by night was carried out in May 2016. In total, 702 spiders were collected, representing 6 families and 25 (morpho-)species. We found that the number of individuals, but not species richness, was highly correlated with the area of sampled forest fragments, suggesting that kipuka act as separate habitat islands for these predatory arthropods. Species richness was significantly lower in the lava matrix outside the kipuka compared to the kipuka habitats, although there was no statistical difference in species composition between the two habitats, largely because of similarity of non-native species in both habitats. Over the last 20 years, the abundance of non-native spider species substantially increased in both kipuka and lava habitats, in marked contrast to the vegetation that has remained more intact. With endemicity of terrestrial arthropods reaching over 95% in native forests, non-native predatory species present a critical challenge to the endemic fauna. [ABSTRACT FROM AUTHOR]

Assessment of habitat restoration often rely on single-taxa approach, plants being widely used. Arthropods might yet complement such evaluation, especially in hard, poorly-diversified environments such as maritime clifftops. In this study we compared the responses of spiders and plants (both at species and assemblage levels) to increasing time of heathland restoration. Sampling took place in different sites of Brittany (Western France), using a replicated design of both pitfall traps and phytosociological relevés. A total of 5056 spiders belonging to 160 species, and 103 plant species were found. No change in species richness between degradation states was found for spiders. Plant species richness was lower in highly degraded habitats of recently restored sites but was not in the oldest restored one. Species composition greatly changed through turnover mechanisms between all sites and degradation states, for both spider and vegetation. Heterogeneity was higher in references states, and increased over restoration time between sites. The number of indicator species decreased with restoration age for spiders, while no indicator species was found for plants. Restoration is still on-going after 15 years, with no recovery of reference assemblages for both plants and spiders, but there were some signals toward reference in the oldest restoration site. Plants and spiders were proved to be complementary bio-indicators of post disturbance restoration, as they bring different, scale-dependent information on restoration success. [ABSTRACT FROM AUTHOR]

Body size is one of the most important individual traits, determining various other life-history traits, including fitness. Both evolutionary and ecological factors shape the body size in arthropods, but the relative contribution of abiotic drivers acting at different spatial scales has been little investigated. We aimed to identify the importance of two broad-scale variables (study region and elevation) in shaping body size of the free-running and locally abundant wolf spider Pardosa palustris (Linnaeus 1758), in contrast to the fine-scaled variable topographic position. Therefore, we set up transects along environmental gradients in the arctic-alpine ecosystems of Norway, which we analyzed using a random forest approach to identify the relative importance of topographic position, elevation, and study region on body size of P. palustris. Our approach revealed that research region was the best explanatory variable, followed by elevation and topographic position. Differences in body size were most likely a consequence of the pronounced differences in season length and the ability of P. palustris to avoid local unfavorable environmental conditions due to its high mobility. [ABSTRACT FROM AUTHOR]

Copyright of Basic & Applied Ecology is the property of Urban & Fischer Verlag and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights: [•] Grassland mowing had negative effects on carabids in the long- and on spiders in the short-term. [•] Cutting date in itself had few effects on spiders and carabids. [•] Even late dates were deleterious for ground-dwelling arthropods. [ABSTRACT FROM AUTHOR]

During the last decades, urban consolidation has been developed to minimize spatial expansion of cities, yet very few studies investigated whether it would actually reduce some negative effects of urbanization on biodiversity. In this study, we compared the invertebrate assemblages associated with two distinct urban forms (compact vs. conventional), focusing on two arthropod taxa often used as bioindicators, and dominant in urban habitats: spiders and carabid beetles. The following parameters were estimated: assemblage composition, species richness, activity-density total, per species (excluding seldom-recorded species) and per size class. The field collection was performed in 2009 using pitfall traps randomly set in hedgerows within 6 sites (representing 251 traps). A total of 4,413 spiders belonging to 117 species and 2,077 adult carabid beetles belonging to 39 species were collected. We found few significant differences in carabid beetle and spider assemblages between the two urban forms. The species richness of both groups was independent from the neighborhood design. Only four species of carabid beetles and ten of spiders significantly reacted to the neighborhood design, and no difference was found among the two designs for all other species. Large carabid beetles were more abundant and small spiders less abundant in the new neighborhood design compared to the conventional one. For both carabid beetles and spiders, no difference in assemblage composition was found between neighborhood designs. We therefore conclude that urban consolidation, by permitting a higher human density with similar arthropod assemblages, could contribute to reduce biodiversity loss in cities. [ABSTRACT FROM AUTHOR]

Urbanization creates human disturbance that plays an important role in ecosystem dynamics. Most of the time, there is a time lag between disturbance and colonization. Opportunistic species with high dispersal power colonize first, while habitat specialist species with a lower power of dispersal colonize later; the communities change with time after disturbance. We hypothesize that, following the establishment of a new neighbourhood, arthropod communities will change from habitat generalists to specialists, and will be more similar to those of the adjacent countryside. We selected two groups of invertebrates often used as bioindicators, spiders and carabid beetles. The following parameters were estimated: assemblage composition, species richness, activity-density total and per life history trait (broad habitat preference). The field data were collected in 2010 within 3 towns located in France. Neighbourhoods of 10 and 30 years old were pair-matched in these towns and sampled using pitfall traps set randomly in hedgerows (120 traps in total). 2101 adult spiders belonging to 89 species were collected, whereas the 643 captured carabid beetles belonged to 24 species. We found no evidence of any significant change in carabid beetle and spider communities according to neighbourhood age. The assemblages were mainly composed of habitat generalist species. These results suggest that urban areas can be seen to be in continual state of disruption, and colonization of these areas is assumed to be relatively rapid (i.e., less than 10 years in our case study), although incomplete. [ABSTRACT FROM AUTHOR]

Dispersal and habitat selection are the main factors that affect the distribution of species in spatially structured habitat. Species typically occurring in an aggregated way are supposed to experience dispersal limitation or to be highly selective for specific habitat attributes in their environment. In order to understand the distribution pattern of a mygalomorph spider species, Atypus affinis, we conducted an intensive survey to detect correlations of spider densities with specific habitat variables and empirically tested the dispersal propensity of spiderlings. In the field, the spiders exhibited an aggregated distribution correlated with patches of heathlands (dominated by Calluna vulgaris). Contrary to our expectations, laboratory experiments revealed a very high dispersal propensity in juveniles (more than 80% of individuals dispersed at least once during two experiments). This dispersal was strongly context dependent with a pronounced negative effect of starvation and a positive effect of clutch size. Kin competition is hypothezised to be the driving force behind these high dispersal abilities. The aggregation of A. affinis is a likely result of habitat use rather than dispersal limitation. [ABSTRACT FROM AUTHOR]

The study of community responses to environmental changes can be enhanced by the recent development of new metrics useful in applied conservation: relative rarity, ecological specialisation and functional diversity. These different metrics have been critically assessed independently, but are rarely combined in applied conservation studies, especially for less-studied taxa such as arthropods. Here we report how these different metrics can complement each other by using the response of spider communities to environmental changes in salt marshes as an example. Sampling took place using pitfall traps in salt marshes of the Mont St Michel Bay (France) during 2004 and 2007. The sampling design was spatially replicated (3 plots per treatment and 4 traps per plot) and encompassed four habitat treatments: control, sheep grazing, cutting (annual, in summer) and invasion by the plant Elymus athericus . We observed contrasting responses of spider communities to the different treatments: grazing had a negative impact on both rarity and functional diversity but a positive impact on specialisation; cutting had a negative impact on the three metrics; and invasion only had a negative impact on rarity and specialisation. These contrasting responses emphasise the necessity of using different complementary community metrics in such conservation studies. Consequently, rarity-, specialisation-, and functional-based indices should be applied simultaneously more frequently, as they potentially provide additional complementary information about communities. Such complementary information is the key to better-informed conservation choices. [ABSTRACT FROM AUTHOR]

• High complementarity between spider and vascular plants as ecological indicators in peat bogs. • High complementarity between diversity metrics in the understanding of ecological patterns. • Landscape and local factors as interwoven structuring drivers of community in peat bogs. Despite their specific biodiversity and the ecosystem services they furnish, peat bogs remain poorly understood, especially in terms of their responses to changes at multiple spatial scales. Many subarctic peat systems face acute risks, due to current global change. In this study, using a multi-metric approach, we assessed the relative value of plants and spiders as ecological indicators in contrasted peat bogs of a French archipelago (St. Pierre-et-Miquelon), located in the North Atlantic. In 2021, pitfall trapping and suction sampling collected spiders while phytosociological relevés were used to document vascular plants. A total of 69 species of spiders and 38 species of vascular plants were identified, and both taxonomic (TD) and functional (FD, based on traits related to dispersal, size and ecosystem functioning) diversity were then estimated for three levels of species relative abundance (Hill numbers q = 0, 1 and 2) using the iNEXT 3D package for alpha diversity as well as iNEXT beta3D for beta diversity. As expected, patterns of TD and FD were highly correlated for each Hill number, but also between Hill numbers for spiders, indicating a surprisingly low effect of species abundance on (spider) diversity patterns. On the contrary, differences between sites were more visible for plants species when species coverage was considered (q = 1 and q = 2), for both TD and FD, and for alpha and beta diversity. RLQ and Fourth corner analyses indicated differences based on functional traits between sites which were significantly associated with relationships between dispersal modes and mostly local factors for plant assemblages. Finally, variance partitioning on assemblage composition showed the importance of an interaction between local and landscape factors for both plants and spiders, with a relatively high importance of local factors alone for plants. Our study thus revealed the high complementary of spider vs. plant assemblage-based metrics as indicators of changing local conditions in peat bogs, confirming these both experience rapid change in subarctic climates. [ABSTRACT FROM AUTHOR]

Despite the role generalist predators may play in biological regulation, the influence of landscape composition in shaping their assemblages remains little studied, especially when landscape interacts with local factors. In this study, we investigated the effects of farming systems along gradients in landscape elements on the structure and composition of carabid and spider assemblages. Twenty pairs of organic vs. conventional spatially-matched fields were sampled in 2013 along increasing percentage covers of organic farming and semi-natural habitats in the landscape. A total of 24241 spiders and 27767 carabids belonging to 120 and 75 species respectively were collected by pitfall traps. Farming systems locally had a strong influence on the community structure (activity-density and species richness) and composition for both spiders and carabids. Structure of spider assemblages was mostly affected by local and landscape factors, whereas that of carabids was more driven by landscape variables and the interaction of the two levels. Spider and carabid community compositions were mostly determined by field farming systems and wood percentage around the field. Our study underlines the importance of landscape context in shaping assemblages of predatory arthropods, and suggests that mechanisms behind the distribution of individual species strongly differ between spiders and carabids. [ABSTRACT FROM AUTHOR]

Despite their ecological importance and diversity, spiders (Arachnida: Araneae) are underrepresented in conservation policies in comparison to other groups. We review all extant conservation tools focusing on spiders in Europe, highlighting general patterns, limitations, gaps, and future directions. We assembled a comprehensive online database reporting all available information concerning the legal protection and conservation status of 4,154 spider species. Existing international legislation has limited coverage, with only one species listed in the Bern Convention and EU Habitats Directive. At the national and subnational levels, 178 species are formally mentioned in the legislation of 19 European countries. Moreover, the International Union for Conservation of Nature (IUCN) includes assessments for 301 species worldwide, 164 of these threatened and eight native to Europe. In addition, spiders are mentioned in Regional Red Lists and Red Books in 28 out of 42 European countries considered in this review. Northern and Central European countries have the highest percentage of species assessed at the regional level in Red Lists and Red Books. The Mediterranean basin has the highest spider diversities in Europe but conservation efforts are lacking, both in terms of assessments and national or subnational legislation. Among European species, Dolomedes plantarius , Argyroneta aquatica and Eresus kollari are the most frequently mentioned in European conservation measures, possibly due to their ecological traits and their strict association with declining habitats. Considering the current threats to spiders in Europe, the protection of large areas of suitable habitat should be considered as the most effective approach to spider conservation. • Spiders are largely underrepresented in conservation policies in Europe. • Only one spider species is listed in the Bern Convention and EU Habitats Directive. • 178 species of spiders are mentioned in the legislation of 19 European countries. • 28 European countries have spider Red Lists or Red Books. • Conservation efforts are lacking in Mediterranean countries. [ABSTRACT FROM AUTHOR]