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Preface to the Proceedings of the 29th European Congress of Arachnology, Brno, 2015 August 24-28

A schizomid, Stenochrus portoricensis Chamberlin, 1922 (family Hubbardiidae), was collected in a greenhouse in Brno. This is the first discovery of a schizomid from the Czech Republic.

The oonopid spiders (Oonopidae), Tapinesthis inermis (Simon, 1882) and Triaeris stenaspis Simon, 1891, are recorded for the Czech Republic for the first time. T. inermis was redetermined from misidentified material and T. stenaspis was discovered in a greenhouse.

Species traits are essential for inferences on ecology and the evolution of organisms. Spiders are the most abundant and diversified terrestrial predators, playing an important role in a range of ecosystem services. Here, I present datasetse on all traits of zodariid spiders, which are known to be free-living ground-dwellers occurring on all continents (except Antarctica) with the highest species diversity in Australia. I collated the data from published resources. The datasets includes nearly 100 000 trait records on all (90) genera and almost all species (1249) of the family. The majority of the 88 traits collected are morphometric, followed by those relating to ecology, reproduction, and physiology. Morphometric traits were available for the majority of species. Other trait classes were only available for some species. I provide a standardized classification of selected categorical traits (habitat, microhabitat, retreat type, circadian activity, prey, primary defensive, and predators). This is the first complete database of traits of a whole spider family, which is available through the World Spider Trait database. [ABSTRACT FROM AUTHOR]

There are various modern pest-control management systems used in the current apple production, such as integrated pest management (IPM) or organic systems. All aims to support occurrence of natural enemies that should help to reduce populations of pests. Here we investigated the effect of fungicide-treated and fungicide-free (resistant tree varieties) treatment combined with biological, IPM, and conventional systems on spiders, as the major group of natural enemies occurring on foliage of apple trees. The biological treatment was based on the use of biopesticides; IPM system was based on the use of selective insecticides, conventional included the use of broad-spectrum insecticides. Abandoned plot served as a control. The study was done for three consecutive years. Spiders were sampled from canopies by beating at weekly intervals during season. We found that fungicide-treated plots had lower abundance of spiders for two years but not species richness than fungicide-free plots. Among the three pest-control management systems, IPM and conventional supported greater spider abundance but not species richness than the biological treatment. Comparison of spider abundance before and after insecticide applications revealed that only very few pesticides, particularly the broad-spectrum ones, reduced spider numbers. In addition, we focused on the comparison of three traits (body size, maturity, fecundity) among treatments. Of six species, only Philodromus cespitum showed a smaller body size on biological than the other treatments. There were three species in which adults occurred earlier on conventional treatment than on the other treatments. Neither clutch size of Phylloneta impressa nor egg size was different among treatments. The small though significant differences in abundance, richness, and selected traits, found among IPM, conventional, and biological treatments and the control show that these pest-control management systems had similar effect on spiders. Use of IPM system combined with scab resistant apple varieties is recommended. [ABSTRACT FROM AUTHOR]

BACKGROUND: In spite of their importance as arthropod predators, spiders have received little attention in the risk assessment of pesticides. In addition, research has mainly focused on a few species commonly found in agricultural habitats. Spiders living in more natural ecosystems may also be exposed to and affected by pesticides, including insecticides. However, their sensitivity and factors driving possible variations in sensitivity between spider taxa are largely unknown. To fill this gap, we quantified the sensitivity of 28 spider species from a wide range of European ecosystems to lambda‐cyhalothrin in an acute exposure scenario. RESULTS: Sensitivity varied among the tested populations by a factor of 30. Strong differences in sensitivity were observed between families, but also between genera within the Lycosidae. Apart from the variation explained by the phylogeny, spiders from boreal and polar climates were more sensitive than spiders from warmer areas. Overall, the median lethal concentration (LC50) of 85% of species was below the recommended application rate of lambda‐cyhalothrin (75 ng a.i. cm−2). CONCLUSION: Our study underlines the high sensitivity of spiders to lambda‐cyhalothrin, which can lead to unintended negative effects on pest suppression in areas treated with this insecticide. The strong differences observed between families and genera indicate that the functional composition of spider communities would change in affected areas. Overall, the variation in spider sensitivity suggests that multispecies investigations should be more widely considered in pesticide risk assessment. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Animal phenotypic traits are utilised in a variety of studies. Often the traits are measured from images. The processing of a large number of images can be challenging; nevertheless, image analytical applications, based on neural networks, can be an effective tool in automatic trait collection.Our aim was to develop a stand‐alone application to effectively segment an arthropod from an image and to recognise individual body parts: namely, head, thorax (or prosoma), abdomen and four pairs of appendages. It is based on convolutional neural network with U‐Net architecture trained on more than a thousand images showing dorsal views of arthropods (mainly of wingless insects and spiders). The segmentation model gave very good results, with the automatically generated segmentation masks usually requiring only slight manual adjustments.The application, named MAPHIS, can further (1) organise and preprocess the images; (2) adjust segmentation masks using a simple graphical editor; and (3) calculate various size, shape, colouration and pattern measures for each body part organised in a hierarchical manner. In addition, a special plug‐in function can align body profiles of selected individuals to match a median profile and enable comparison among groups. The usability of the application is shown in three practical examples.The application can be used in a variety of fields where measures of phenotypic diversity are required, such as taxonomy, ecology and evolution (e.g. mimetic similarity). Currently, the application is limited to arthropods, but it can be easily extended to other animal taxa. [ABSTRACT FROM AUTHOR]

Forest harvest detection techniques have recently gained increased attention due to the varied results they provide. Correctly determining the acreage of clear-cut areas is crucial for carbon sequestration. Detecting clear-cut areas using airborne laser scanning (ALS) could be an accurate method for determining the extent of clear-cut areas and their subsequent map display in forest management plans. The shapes of ALS-detected clear-cut areas have uneven edges with protrusions that might not be readable when displayed correctly. Therefore, it is necessary to simplify these shapes for better comprehension. To simplify the shapes of ALS-scanned clear-cut areas, we tested four simplification algorithms using ArcGIS Pro 3.0.0 software: the retain critical points (Douglas–Peucker), retain critical bends (Wang–Müller), retain weighted effective areas (Zhou–Jones), and retain effective areas (Visvalingam–Whyatt) algorithms. Ground-truth data were obtained from clear-cut areas plotted in the forest management plan. Results showed that the Wang–Müller algorithm was the best of the four ALS algorithms at simplifying the shapes of detected clear-cut areas. Using the simplification algorithm reduced the time required to edit polygons to less than 1% of the time required for manual delineation. [ABSTRACT FROM AUTHOR]

Specialists possess specialized trophic adaptations. Spiders of the genus Palpimanus Dufour, 1820 are araneophagous spiders which also catch alternative prey. They have morphological, behavioral, and venomic adaptations tuned to higher efficacy in the capture and processing of other spiders. Here, we tested the hypothesis whether Palpimanus can develop on two prey types. We reared spiderlings of Palpimanus spp. on a diet composed of spiders and of insects, and recorded their performance. We found that Palpimanus exhibited significantly higher mortality on the insect diet. In fact, only spiderlings on the spider diet were able to develop. The developmental rate was slow, as one instar lasted on average more than 60 days. On the basis of this finding, we estimated that the life cycle is at least biennial. We conclude that Palpimanus spiders possess specialized prey-capture adaptations towards spider prey which prevent them to utilize alternative prey. [ABSTRACT FROM AUTHOR]

Many prey species employ multiple defenses during interactions with predators. Multiple defenses can provide a selective advantage against a single predator at different stages of the interaction or attack, as well as against multiple predator types. However, the efficacy of multiple defenses both during different sequences of an attack and against multiple predator types, remains poorly understood. We measured and classified defensive traits used by five mimics (Müllerian and Batesian) of the myrmecomorphic golden mimicry complex and one non-mimetic species. We then performed predatory trials using two different predators that differed markedly in their body size, trophic specialization, and how they handle prey—one being an ant specialist (spider) and the other a generalist which avoided ants (skink). We identified 12 defensive traits and classified them into four groups (primary, chemical, mechanical, and behavioral), which were strongly correlated. Skinks were much less likely to attack and capture mimics than the ant-eating spider predators. Our results show that multiple defenses (five or six) were used against each predator. The defensive behaviors and features that were most effective against skinks included appendage waving and large body size, whereas the golden "shine" warning signal, large body size, cuticle thickness, and defensive gland size were most effective against spiders. Most defenses appeared to be predator-specific. We conclude that potential prey in the golden mimicry complex have been selected for multiple defenses because of their vulnerability to different predator types and consequently, the efficacy of some of these defenses likely represents a trade-off. [ABSTRACT FROM AUTHOR]

This study explores the eff ect of nutritional composition on the fi tness of consumers in a quadri-trophic food web. Specifi cally, we studied how enrichment of the food of fruit fl ies Drosophila melanogaster (Meigen, 1830) transfers to the spider Phylloneta impressa (L. Koch) (Theridiidae) and its parasitoid wasp, Zatypota percontatoria Mueller (Ichneumonidae). We reared fruit fl ies on balanced, protein-enriched, and lipid-enriched diets, and observed several fi tness-related traits in both the predator and the parasitoid. In spiders, we did not fi nd signifi cant diff erences among treatments in their body size and the probability of building a cocoon web. In parasitoids, we failed to fi nd signifi cant diff erences among treatments in the time to wasp pupation, the duration of pupation, the length of the wasp tibia and pronotum, and the body mass. However, the sex ratio of hatched wasps diff ered signifi cantly among treatments from the expected 1 : 1. In the balanced diet group, the majority of wasps were males. There was a signifi cant positive relationship between the spider prosoma size and the length of the wasp fore wing. Our results suggest that the quality of the food of the primary consumer had little eff ect on the fi tness of the organism at the fourth trophic level. [ABSTRACT FROM AUTHOR]

The numbers per tiller (abundance) and per unit area of ground (population density) of the dominant cereal aphids in winter wheat crops, Sitobion avenae (Fabricius) and Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) were recorded from 2000–2015. The results were used to test the hypothesis that at the population peak and 4 weeks previously, the population density of aphids in winter wheat crops (Triticum aestivum L., Poaceae) is uniformly distributed with respect to surface area and, as a result, their abundance is high in sparse stands (SPA) where the colonizing aphids are scattered among a small number of tillers (ca. 80 m−2), and low in dense stands (DEN) where they are scattered among a larger number of tillers (ca. 440 m−2). This prediction was verified for S. avenae, the population density of which did not significantly differ between SPA and DEN stands throughout this period. This species feeds mainly on the ears, whose nutritional quality for aphids varies little with crop density and during the course of ripening. In contrast and contrary to our prediction, the population density of M. dirhodum increased throughout this period more rapidly in SPA than in DEN stands. This species lives on leaves whose quality is better and remain present for longer during the course of ripening of the crop in SPA than DEN stands. The abundance of both species was higher in SPA than in DEN stands. Greater direct damage to cereal crops can be expected when using technologies and cultivars of winter wheat that need to be planted sparsely. [ABSTRACT FROM AUTHOR]

An analysis of the diets of reptiles is essential for understanding the role of reptiles in the ecosystem and the employment of successful conservation management plans. For this purpose, noninvasive and invasive methods to identify consumed prey have been used. Here, we investigated the diet of male and female European Green Lizards (Lacerta viridis) by sampling fecal pellets across 2 yr in the spring and late summer at a single site. We used the following two methods for identifying prey remnants from fecal samples: the classical macroscopic approach that requires competent expert knowledge and the molecular approach based on the dietary metabarcoding of nondegraded prey remnant DNA. According to both methods, lizards consumed mainly insects belonging to 13 orders, with Coleoptera as the dominant prey. The number of prey taxa was similar between the sexes, but the prey composition at the genus level was significantly different, with males capturing some coleopterans more than females. The diets also differed significantly between season. In the spring, lizards consumed many more prey types and many more coleopteran specimens than in late summer. The proportion of identified prey taxa was significantly different between the identification methods. From the total of identified prey, macroscopic identification yielded only about 50% of taxa, whereas molecular identification yielded more than 80% of taxa. Our results show that molecular identification can recover a much higher number of prey than the macroscopic method, yet not all prey. Thus, the integration of both methods best described the natural diet and complex trophic interactions of European Green Lizards. [ABSTRACT FROM AUTHOR]

Ecological specialists constitute relevant case studies for understanding the mechanisms, potential and limitations of evolution. The species-rich and strictly myrmecophagous spiders of the genus Zodarion show diversified defence mechanisms, including myrmecomorphy of different ant species and nocturnality. Through Hybridization Capture Using RAD Probes (hyRAD), a phylogenomic technique designed for sequencing poorly preserved specimens, we reconstructed a phylogeny of Zodarion using 52 (approx. a third of the nominal) species that cover its phylogenetic and distributional diversity. We then estimated the evolution of body size and colour, traits that have diversified noticeably and are linked to defence mechanisms, across the group. Our genomic matrix of 300 loci led to a well-supported phylogenetic hypothesis that uncovered two main clades inside Zodarion. Ancestral state estimation revealed the highly dynamic evolution of body size and colour across the group, with multiple transitions and convergences in both traits, which we propose is likely indicative of multiple transitions in ant specialization across the genus. Our study will allow the informed targeted selection of Zodarion taxa of special interest for research into the group's remarkable adaptations to ant specialization. It also exemplifies the utility of hyRAD for phylogenetic studies using museum material. [ABSTRACT FROM AUTHOR]