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Modulation of predatory behaviors based on prey profitability can improve overall foraging efficiency by allocating energy reserves towards more valuable prey. Should the value of prey vary predictably across the landscape, predators could also benefit from the utilization of environmental cues to inform their foraging decisions. Here, we present data on context-dependent foraging behaviors of the wolf spider Pardosa milvina (Araneae: Lycosidae). Spiders underwent testing during which subjects were alternately provided cricket prey coated with either a favorable (sucrose) or unfavorable (quinine) solution. Each prey type was paired with 1 of 2 environmental odors such that one odor was always predictive of unfavorable prey and the other was always predictive of favorable prey. We found that P. milvina reduced their attacks over time while differing significantly in behavior towards the 2 prey types. The rate of nonresponses towards the unfavorable prey increased significantly over time compared to the favorable prey, suggesting that spiders were avoiding the former. Our findings indicate that P. milvina can differentiate between environmental odor cues associated with prey type. Additionally, we report on a novel prey handling behavior where spiders would repeatedly drag unfavorable prey along the arena floor between bouts of cheliceral grooming. We propose this behavior may have served to remove quinine from the prey. [ABSTRACT FROM AUTHOR]

Many animals communicate using multiple sensory modes (e.g., vibratory, visual, chemical), and there is current interest in the role of multimodal signals in mate choice. We tested the hypotheses that male Gladicosa bellamyi wolf spiders (Lycosidae) court females using multimodal signals and that these signals were related to male mating success. Using a laser Doppler vibrometer and video camera, we characterized the vibratory and visual courtship signals of male G. bellamyi. Males courted females with a vibratory signal made of three components: pulses of stridulation, abdominal percussion, and a third unknown percussive element (presumed to arise from rapid abdomen tapping), along with two unique visual displays, a foreleg extension/tap and squared leg arch. Female G. bellamyi show no apparent vibratory signals, but possess visual receptivity displays comparable to some other female lycosid species. We found a strong correlation between the vibratory stridulation component and the visual foreleg extension/tapping display of males, suggesting a multimodal signal. Higher rates of courtship signaling, both visual and vibratory, were associated with increased copulatory success. We conclude that male G. bellamyi exhibits multimodal courtship communication, with simultaneous complex vibratory signals and visual displays, and that higher rates of these signals increase the probability of mating in this species. [ABSTRACT FROM AUTHOR]

Spiders are an abundant group of natural enemies preying on insect pests in agroecosystem. But their potential in biological control has not been fully realized due to difficult mass production. One hindrance is the intense intraspecific aggression in spiders. Neurotransmitters such as serotonin play important roles in modulating aggression. Here, we investigated the regulatory function of serotonin (5‐hydroxytryptamine [5‐HT]) signaling in the intraspecific aggression in a wandering spider Pardosa pseudoannulata (Araneae, Lycosidae). The aggression was quantified with 5 escalated aggression behaviors as approach, chasing, lunging, boxing, and biting. Virgin (VG) females exhibited higher aggression levels but less 5‐HT content than post‐reproductive (PR) females. Systemic increase of 5‐HT via 5‐HT injection decreased aggression, while decrease of 5‐HT via RNA interference (RNAi) of the tryptophan hydroxylase gene, increased aggression. The involvement of the four 5‐HT receptors were determined via individual or combined RNAi. Co‐RNAi of the three 5‐HT1 genes increased overall aggression with decreased incidents of approach, chasing, lunging, and increased biting. RNAi of 5‐HT1B decreased approach and increased biting, whereas RNAi of 5‐HT1A or 5‐HT1C did not affect aggression. RNAi of 5‐HT7 decreased approach only. Therefore, different 5‐HT receptor types contribute to different aspects of the inhibitory effects of 5‐HT on aggression and provide several pharmacological targets for manipulating spider aggression. 5‐HT injection did not affect spiders’ predation on their insect prey, the brown planthopper Nilaparvata lugens. The findings reveal 1 neuronal mechanism regulating intraspecific aggression in spiders and provide an insight in developing aggression suppression strategies for spider mass rearing. [ABSTRACT FROM AUTHOR]

Maternal care is critically important for the survival of offspring in various animals. Spiders in the family Lycosidae are known for their hunting ability and maternal care behaviors. Predation on newly hatched spiderlings (pulli) by mother spiders decreases when they come into contact, and they carry the pulli on their dorsal surface. However, the factors inducing maternal care in lycosid spiders have not been elucidated. In this study, we investigated maternal care in Pardosa pseudoannulata (Araneae, Lycosidae) females. We proposed that the physical interaction between pulli and mother spiders induces maternal care via m‐aminophenylacetylene (m‐A), a novel regulator of maternal care. The presence of pulli on the dorsal abdomen of non‐mother spiders suppressed pulli predation and increased the pulli‐carrying rate, and the absence of pulli on the mother spiders increased pulli predation and decreased the pulli‐carrying rate. The compound m‐A was abundant in mother spiders, and it could be induced in non‐mother spiders when they carried pulli. The topical application of m‐A to non‐mother spiders and m‐A injection decreased pulli predation and increased the pulli‐carrying rate, respectively; these findings indicate that m‐A in both internal tissues and the integument is required for the induction of maternal care behavior, and the interaction between pulli and females induces the production of m‐A. In‐depth study of the regulatory mechanism of maternal care will enhance our understanding of spider biology and behavior. [ABSTRACT FROM AUTHOR]

The wolf spider Pardosa astrigera L. Koch, 1878, an important biological control agent for pests in agriculture, is widely distributed in various ecosystems across East Asia. This study used mitochondrial DNA and aimed to provide an in-depth understanding of population genetic structure and evolutionary history throughout the species. Mitochondrial gene sequences from 107 samples of P. astrigera from 25 East Asian populations were used for genetic analyses. Our data revealed an asymmetric phylogeographic distribution in two sympatric lineages (1–2) of P. astrigera in continental East Asia. The spatio-temporal pattern of two mitotypes of P. astrigera in this region gives strong support for a Northeast Asian origin during the late Pleistocene (~1.69 million years ago) and the population expansion time of ~74,340 (58,832–104,236) years ago (during the last glacial period) and dual colonization around East Asia from two directions: from North to South and from East to West. Our phylogeographic results suggested that Pleistocene climate oscillations with subsequent fragmentation events and secondary contacts were the major impact factors of the diversification, geographic distribution, and expansion patterns of P. astrigera, and human activities and ballooning probably accelerated its recent dispersal. [ABSTRACT FROM AUTHOR]

Changes in the animals' environment often impact on their behavior and the way they communicate. Particularly in spiders, living on webs or not is a determining factor. While the Lycosidae family predominantly comprises wandering spiders, only a few species inhabit webs. Aglaoctenus oblongus (C.L. Koch 1847) challenges this norm, as it has been found both in webs and wandering, suggesting a previously undocumented mixed strategy. This study aims to: (1) describe the sexual behavior of A. oblongus under laboratory conditions and (2) utilize phenological data to elucidate when and where mating occurs. Sexual encounters were observed within and outside webs, with minimal differences noted between them. Courtship was characterized by groping and leg shaking performed by the males. Copulation was lengthy (near to seven hours), featuring an irregular pattern of palpal insertions, and culminating in a backward dismount. Individuals showed a mixed life history, with the spiders most often found in webs being females with eggs. Both sexes were found throughout the year, with a peak in autumn. We compare the sexual characteristics of this species with that of A. lagotis (also belonging to the Sosippinae subfamily), the only other wolf spider studied to date that exclusively inhabits webs. [ABSTRACT FROM AUTHOR]

Natural vegetation in and around crops effectively increases predators. Semi‐natural habitats (SNHs; non‐crop vegetation) surrounding crops provide refuge and resources. However, the function of SNHs may depend on several factors, and the response of natural predators may vary among crops and regions. Here, we examined the spider community in a SNH and at an adjacent vineyard in a semi‐arid region of Argentina. We collected spiders in a gradient from an adjacent SNH, towards the vineyard at three distances from the SNH using two techniques: beating and pit‐fall traps. We collected spiders in December and February during two consecutive years at two strata: in vegetation and on the ground. In vegetation, spider abundance significantly decreased from SNH towards the interior of the vineyard at 80 m. On the ground, spider abundance was also significantly higher in SNH. However, after decreasing at the 5 and 20 m sites inside the vineyard, the abundance increased at 80 m. For foliage spiders, species richness followed the same pattern as abundance, whereas ground spider richness significantly increased from SNH to the interior of the vineyard. Species composition also showed different tendencies between foliage and ground spiders. The foliage spider community differed between SNH vs. all the vineyard sites. Contrarily, at the ground stratum, SNH was similar in composition to the edge of the vineyard, and they both differed from the other vineyard sites. We found that the adjacent SNH influenced the spider community in the vineyard and that this effect depended on the distance from that habitat and the association of the community to various strata. These results highlight the importance of studying the whole community of spiders when aiming to increase predator abundance to enhance biological control in this kind of crop. In addition, we found species that may act as indicators of native vegetation which has important implications for the management of natural habitats in this region. [ABSTRACT FROM AUTHOR]

We examined the role of lycosid eye rows and the pairs of eyes within each row in prey detection and mate recognition by Schizocosa ocreata (Hentz, 1844) using two approaches: (1) occluding anterior or posterior eye rows; and (2) occluding all but a single eye pair. In response to live prey, females took longer to orient and approach crickets when the posterior eye row was occluded; responses were intermediate when the anterior eye row was occluded. With six of eight eyes occluded, spiders that could see with posterior lateral eyes (PLE-only) detected the cricket as quickly as the fully sighted spiders (controls), while spiders limited to seeing from other eye pairs took longer to orient towards prey. Orientation distance varied significantly as well, with Control, ALE-only, PME-only and PLE-only spiders responding at greater distances than AME-only spiders. To analyze the functions of the eye rows involved in mate preference in S. ocreata, we conducted an additional study with presentation of video playback of a courting male to females with different eye rows occluded. Females with their posterior eyes occluded took longer to orient and respond compared to controls and anterior eye row occlusion. The sum of female receptivity displays was also significantly reduced when posterior eyes were occluded, suggesting the posterior eyes may be involved in mate recognition. Taken together, these data suggest that the posterior (secondary) eyes may have an important role in detection and identification of both prey and courting males. [ABSTRACT FROM AUTHOR]

The lycosid spider species Piratula hurkai (Buchar, 1966) is reported for the first time from Türkiye. The habitus and palpal organ of this species were photographed. The locality record where the species was collected is indicated on a map. [ABSTRACT FROM AUTHOR]

Ballooning 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. [ABSTRACT FROM AUTHOR]

Resistance to mating by females has been hypothesized as a tactic to assess potential mates and avoid undesirable ones. Previous studies show infection with the pathogenic bacteria, Pseudomonas aeruginosa, triggers a costly immune response and negatively impacts fitness in the wolf spider Schizocosa ocreata (Hentz 1844). Studies also show that infection can be transmitted during copulation, suggesting that there are potential fitness costs associated with mating with an infected individual. We examined impacts of infection on mating interactions of male and female S. ocreata. As studies show infection can be detected through chemical cues, we tested whether males or females avoid mating with infected individuals when given the opportunity. We paired infected and uninfected (control) males and females and recorded their behavior. We found that mating outcome was independent of infection for males and females. While higher male courtship rates and more frequent female receptivity displays were associated with successful mating, we saw no direct effect of infection status on mating outcome. However, among spider pairs that did not mate, females were found to be significantly more resistant and aggressive toward infected males than control males. Male aggression, on the other hand, was greater in pairs that did result in mating. These results suggest that sexual conflict in mating can be related to infection status, and that females can recognize infected males and alter their behavior in response. [ABSTRACT FROM AUTHOR]

Generalist arthropod predators forage not only to gain energy and nutrients, but also to obtain a balanced intake of macronutrients (the intake target). We test two opposite hypotheses concerning the predation rate of nutritionally imbalanced predators: It will increase (1) if the prey is rich in macronutrients that the predator is short of, or (2) if the prey is low in macronutrients that the predator is short of. We used the wolf spider Pardosa amentata (Clerck) as the predator and nutritionally manipulated Drosophila melanogaster Meigen as prey. We completed a full factorial experiment with eight treatment groups, in which we measured predation, consumption and prey utilization of high-protein (HP) and high-lipid (HL) flies by spiders that were previously treated with either HP- or HL-flies for two or six days. The results supported hypothesis 2. Whether spiders had been previously fed HP-or HL-flies, those that were tested against the same type of fly killed more than those tested against the opposite type of fly. A likely explanation for this result is that the predator will be unable to reach its macronutritional intake target by continued feeding on the same prey. It will stay nutritionally imbalanced and continue to catch prey in an attempt to redress its imbalance. In natural systems, predation rates may thus be increased by the widespread mismatch between predators' nutritional demands and what is available in prey. In practical biological control, it suggests a beneficial effect of feeding the predator prior to release with the pest it is intended to control. [ABSTRACT FROM AUTHOR]

Spiders may be adversely affected by pesticides, yet they are not included in regulatory risk assessment and a related standard guideline to test their sensitivity to chemicals is lacking. Different laboratory setups, including test temperature and relative humidity, have been shown to influence the sensitivity of spiders. The climate from which spiders originate and the rearing conditions in the laboratory prior to ecotoxicological testing may also alter their sensitivity to chemicals, potentially in interaction with test conditions. We investigated the influence of population origin, rearing and test temperature on the chemical sensitivity of the spider Pardosa amentata towards lambda‐cyhalothrin. We collected female P. amentata carrying egg sacs from two climates, i.e., boreal and cool temperate. Spiders were kept in the laboratory and their offspring were reared and tested at 15, 20 and 25°C. Hatching of egg sacs largely failed at 15°C, while a moderate spiderling mortality (40%) was recorded at 20°C. At 25°C, mortality increased (63%) and a faster developmental rate was observed. Rearing and test temperature had no significant effects on spider chemical sensitivity. However, spider chemical sensitivity differed between populations, with spiders from boreal climate being 38% more sensitive than spiders from cool temperate climate. A higher sensitivity towards lambda‐cyhalothrin increases the risk of population reduction in treated areas, with potential alterations of ecosystem functions such as biological control. Our results suggest that the climatic origin of test organisms deserves stronger attention in ecotoxicological research. [ABSTRACT FROM AUTHOR]

We used video playback of courting male Schizocosa ocreata wolf spiders to examine responses of intended receivers (conspecific females) and eavesdroppers (competitor males, predatory spiders, toads) to manipulations of spider color (natural color, monochromatic gray, monochromatic RBG average) displayed against complex leaf litter backgrounds (color, grayscale). Models of chromatic and achromatic contrast between spider stimuli and backgrounds were used to predict receiver responses. The results support the hypothesis that interactions between spider and background coloration affect detection and recognition, although responses varied with receiver type. Detection responses of intended receivers (female S. ocreata) did not fit predictions of the chromatic contrast model in some cases, but showed a fair fit to the achromatic model. Detection responses of social eavesdroppers (male S. ocreata) fit the chromatic and achromatic contrast models slightly better than did female responses (poor fit and very good fit, respectively). Eavesdropping wolf spider predators (Rabidosa) exhibited detection responses that significantly matched predictions of the chromatic (very good fit) and achromatic (excellent fit) models. Whereas jumping spiders (Phidippus) showed a good fit to the chromatic and achromatic contrast models, toad predators had a good fit only to the chromatic model. Recognition responses revealed a different pattern of fit to the chromatic and achromatic models across receiver types, although Rabidosa again indicated a significant fit to both models. Taken together, the results of this study identify both chromatic and achromatic features of spider appearance as likely explanations for differences in behavioral responses of intended and unintended receivers. This outcome suggests the possibility that both sexual and natural selection likely target different features of male appearance during courtship.Significance statement: Some of the most striking examples of animal displays involve conspicuous male courtship signals, although such signals often can be exploited by eavesdropping competitors and predators. In this study we manipulated the coloration of courting male Schizocosa ocreata wolf spiders and their leaf-litter backgrounds from pre-existing video footage. We then played back the altered video clips to female conspecifics and eavesdroppers (competing conspecific males and potential predators: non-conspecific wolf spiders, jumping spiders, and toads) and recorded their responses. From these responses we scored both stimulus detection (latency to orient) and recognition (receptivity movements in conspecific females, tapping bouts in conspecific males, and attack in other viewers). Color differences in the courting male stimuli and leaf-litter backgrounds proved to be important for detection and recognition, even for wolf spiders with limited dichromatic vision. Moreover, for jumping spiders and predatory toads with tetrachromatic and trichromatic vision respectively, color of the prey spider stimulus was particularly salient. Overall, our experimental results support the hypothesis that receivers with different visual capacities should vary in their responses to color and contrast of courting male spiders against complex backgrounds. [ABSTRACT FROM AUTHOR]

Various strategies have evolved to protect animals from predators. We explored the activity and predation risk experienced by two species of aphid. Both species will drop from plants when disturbed and face a suite of predators, including wolf spiders, when they reach the ground. We focused on Aphis fabae Scopoli and Aphis nerii Boyer de Fonscolombe (Hemiptera: Aphididae, Aphidini); A. nerii sequesters cardiac glycosides when it feeds on milkweed. We explored the interactions between these aphids and the wolf spider Pardosa milvina Hentz (Araneae: Lycosidae) that is likely a predator they encounter when they are not on their host plants. We hypothesized that there would be differences in the susceptibility of the two species to predation and that the more vulnerable species would react more strongly to substrate‐borne cues deposited by the spider. We predicted that any behavioral reactions that the aphid displayed in response to predator cues would be effective in reducing risk. We documented the activity of each aphid species on chemotactile cues from P. milvina and measured predation rate in arenas with and without those same cues. Aphis fabae altered their activity in the presence of P. milvina cues but A. nerii did not. Likewise, A. fabae was more susceptible to predation by P. milvina when no cues were present, but when cues were present, predatory success was much lower. Aphis nerii, the less desirable prey for this predator, moved less and had a different locomotory pattern than A. fabae in control trials with no spider cues and so we cannot determine whether its chemical protection or activity were more important in reducing predation levels. These results provide insight into the risks faced by aphids when they are off of their host plant and in a barren environment. [ABSTRACT FROM AUTHOR]

In the multimodal communication of Schizocosa ocreata wolf spiders, males respond to chemical signals from females with visual and substrate-borne vibratory signals for courtship. We examined the effect of wet vs. dry leaves on transmission of male courtship signals, responses of male spiders to female chemical cues, responses of courting males to bird calls indicating predator presence, and mating success. Laser Doppler vibrometry showed that spider stridulation and percussive signals maintain higher amplitude over distance on dry leaves than on wet leaves. Male response to chemical cues (courtship latency and rate) declined after leaves with female silk became wet. In response to predatory bird calls (Blue Jays) transmitted through leaf surfaces, courting male spiders on dry leaves responded with anti-predator "freeze" behaviors more often and with longer duration than those on wet leaves, and with longer latency to return to courtship on wet leaves. Laser Doppler vibrometry confirmed that bird calls on dry leaves had significantly greater average amplitude and different spectral profiles than those on wet leaves. Males courted females on wet and dry leaves with equal frequency, but subsequent mating success was significantly greater on dry leaf litter. Interestingly, visual signals increased on wet leaves, suggesting compensatory behavior in response to moisture. Given a predicted change in precipitation in parts of North America because of global climate change, these results suggest potential for impact on behavior of invertebrates at the microhabitat level. [ABSTRACT FROM AUTHOR]

Abstract DNA metabarcoding is increasingly used to analyze the diet of arthropods, including spiders. However, high sensitivity to DNA contamination makes it difficult to apply to organisms obtained from mass‐sampling methods such as pitfall traps. An alternative is to hand‐sample spiders, but it is unclear how effectively this prevents external contamination, especially with new knowledge showing the wide spread of eDNA in the environment. Protocols using bleach to remove external DNA have been tested on several invertebrates, though testing with both mass‐sampling methods and spiders is lacking. Here, we used wolf spiders (Lycosidae) to assess the risk of external DNA contamination from pitfall trapping and hand sampling, and the efficacy of bleach decontamination. We first conducted a contamination experiment where we placed spiders in pitfall traps containing trapping medium and a nonprey insect species to simulate external DNA contamination. We also compared sampling methods by collecting spiders using pitfall traps and hand sampling. Spiders from the contamination experiment and sampling method comparison were either bleached or untreated, then metabarcoded using multiple primer pairs. The contamination experiment resulted in the contamination of almost all spiders from pitfall traps, which was successfully eliminated with bleaching. Interestingly, there was no difference in the number of amplicon sequence variants (ASVs) detected per spider between pitfall trapping and hand sampling but bleaching resulted in significantly fewer ASV detections for both methods. Additionally, bleaching, but not sampling method, affected the taxonomic diet composition for both hand‐sampled and pitfall‐trapped spiders, indicating similar levels of external contamination. Our results are the first to confirm that DNA metabarcoding can be used together with bleaching for spiders sampled from pitfall traps, and that hand sampling does not necessarily exclude external DNA contamination. Thus, diet studies using metabarcoding should address the risk of external contamination with field‐sampled arthropods, regardless of sampling method.

Holarctic species offer great opportunities to study biogeography, phylogenetics, taxonomy, and local adaptation. Species that are considered conspecific between the Palearctic and the Nearctic realms are often split into 2 or more species when denser sampling and molecular markers are applied. Similar in complexity but at a finer geographical scale are species groups having Arctic-Alpine distributions where lineages have complicated demographic histories due to glacial dynamics. In both cases, allopatric speciation might not result in fast differentiation of morphological characters if environmental conditions in isolated areas are similar and the main driver of variability is genetic drift. Here, we study the Holarctic Pardosa hyperborea (Thorell, 1872) and its closest European relatives to assess their taxonomic status and patterns of genetic variability. Based on DNA barcodes and genomic data from double-digest restriction site associated sequencing, we propose that the North American populations should be regarded as a distinct species (P. luteola Emerton,1894, stat. resurr.), possibly consisting of several independent lineages. With the help of D-statistics, population genetic simulations and phylogenetic networks analysis, we demonstrate historical introgression among European species of the group and a likely explanation for shared DNA barcodes among allopatric and fully differentiated species. Our study exposes a promising model for studying speciation processes and demographic history in parallel on both sides of the Atlantic Ocean and demonstrates the usefulness of genomic tools in elucidating the taxonomy and biogeography of taxa across broad geographic scales. [ABSTRACT FROM AUTHOR]

The material in the present study was collected from two agricultural regions in Thi-Qar and Basrah Provinces, southern Iraq. Pardosa roscai (Roewer, 1951) was recorded for the first time from Thi Qar Province in Iraq. А list of wolf spiders (Araneae, Lycosidae) from Iraq is presented. In addition, a map of the areas, with a taxonomic review and confirmation of five species of wolf spiders is given, with photographs of palp and epigyne of several species, which were not published in previous studies. [ABSTRACT FROM AUTHOR]

The material in the present study was collected from two agricultural regions in Thi-Qar and Basrah Provinces, southern Iraq. Pardosa roscai (Roewer, 1951) was recorded for the first time from Thi Qar Province in Iraq. А list of wolf spiders (Araneae: Lycosidae) from Iraq is presented. In addition, a map of the areas, with a taxonomic review and confirmation of five species of wolf spiders is given, with photographs of palp and epigyne of several species, which were not published in previous studies.

The gut microbiomes of arthropods have significant impact on key physiological functions such as nutrition, reproduction, behavior, and health. Spiders are diverse and numerically dominant predators in crop fields where they are potentially important regulators of pests. Harnessing spiders to control agricultural pests is likely to be supported by an understanding of their gut microbiomes, and the environmental drivers shaping microbiome assemblages. This study aimed to deciphering the gut microbiome assembly of these invertebrate predators and elucidating potential implications of key environmental constraints in this process. Here, we used high-throughput sequencing to examine for the first time how the assemblages of bacteria in the gut of spiders are shaped by environmental variables. Local drivers of microbiome composition were globally-relevant input use system(organic production vs. conventional practice), and crop identity (Chinese cabbage vs. cauliflower). Landscape-scale factors, proportion of forest and grassland, compositional diversity, and habitat edge density, also strongly affected gut microbiota. Specific bacterial taxa were enriched in gut of spiders sampled from different settings and seasons. These findings provide a comprehensive insight into composition and plasticity of spider gut microbiota. Understanding the temporal responses of specific microbiota could lead to innovative strategies development for boosting biological control services of predators. [ABSTRACT FROM AUTHOR]

The family Lycosidae is one of the spider families with the greatest diversity of species and with varied and striking strategies. Studies on Neotropical wolf spiders have contributed new and valuable information to the field of sexual selection for several decades, having discovered cases that differ markedly from previously known patterns, not only for the family but for spiders in general. Here we provide a review of studies on reproductive biology of South American wolf spiders in recent decades, focusing on the subfamilies Lycosinae, Allocosinae and Sossipinae. The promising possibilities of the spiders of this family to test fundamental hypotheses in sexual selection and reproductive biology are highlighted, and we outline areas of particular interest for future studies. We hope that this review will inspire further studies on a broader range of wolf spider species in the Neotropics. [ABSTRACT FROM AUTHOR]

The mitochondrial genome (mitogenome) is useful for identification and phylogenetic analyses among arthropods, but there are no sufficient mitogenome data for wolf spiders. To enrich the mitogenome database of wolf spiders, the complete mitogenome of Pardosa pusiola was sequenced by high‐throughput sequencing. It is 14,284 bp, comprising 13 protein‐coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and a control region (CR). It represents a high bias toward A and T nucleotides with an A + T content of 76.49%. The mitogenome exhibited a negative AT skew (−0.13) and a positive GC skew (0.32). Most PCGs started with ATN codons and ended with TAA, TAG, or an incomplete T. In addition, most tRNAs had aberrant secondary structures with the absence of DHU arm or TΨC arm. Analysis performed with CREx software demonstrated that large‐scale rearrangements of tRNAs were observed in the mitogenome of P. pusiola as compared with the putative ancestral mitogenome. The Bayesian inference (BI) and maximum likelihood (ML) phylogenetic trees based on the 13 PCGs of 25 spiders had the same topology, which could be presented as (Araneidae + (Agelenidae + (Dictynidae + Desidae)) + (Salticidae + (Thomisidae + (Oxyopidae + (Pisauridae + Lycosidae))))). This study offers a useful genetic resource for the taxonomy and phylogeny of spiders. [ABSTRACT FROM AUTHOR]

Niche differentiation and intraguild predation (IGP) can allow ecologically similar species to coexist, although it is unclear which coexistence mechanism predominates in consumer communities. Until now, a limited ability to quantify diets from metabarcoding data has precluded the use of sequencing data to determine the relative importance of these mechanisms.Here, we pair a recent metabarcoding quantification approach with stable isotope analysis to examine diet composition in a wolf spider community.We compare the prevalence of resource partitioning and IGP in these spiders and test whether factors that influence foraging performance, including individual identity, morphology, prey community and environmental conditions, can explain variation in diet composition and IGP.Extensive IGP is likely the primary coexistence mechanism in this community, and other factors to which foraging variation is often attributed do not explain diet composition and IGP here. Rather, IGP increases as prey diversity decreases.Foragers are driven to IGP where resource niches are limited. We highlight the need to examine how drivers of predator–prey interaction strengths translate into foraging in natural systems. [ABSTRACT FROM AUTHOR]

While members of the choosier sex often prefer courting mates with bright, large, or loud phenotypes, social experience can result in variation in mate preferences. Fewer studies, though, have investigated how multiple social parameters might interact to affect such preferences. In the brush-legged wolf spider, Schizocosa ocreata, asynchrony of maturation between sexes provides a time period in which females might be exposed to male courtship prior to making a mating decision. We tested whether adult females demonstrated plasticity in their preferences for vibratory signal amplitude after experience with vibratory playback during their penultimate stage. Penultimate instar females were presented unimodal vibratory courtship signals via piezoelectric disc benders, manipulating the perceived encounter rate (every other day or once per day), the number of males (one or two), and/or the vibratory amplitude (low or high). As adults, each female was presented vibratory playback of a low- or high-amplitude courtship signal in both no-choice and two-choice designs. In no-choice trials, previous experience with different amplitude signals significantly affected adult preferences, while other social parameters did not. Specifically, female S. ocreata preferred high-amplitude signals to low-amplitude signals if previously exposed to high-amplitude signals, while those previously exposed to low-amplitude signals preferred low-amplitude signals. In two-choice trials, however, females preferred high-amplitude signals regardless of their previous social experience, suggesting that innate preferences for high-amplitude signals might outweigh any learned preferences in some contexts. Results from this study complement previous social experience studies in S. ocreata, by clearly demonstrating a second sensory modality through which social learning can occur. Significance statement: Social experience affects subsequent mate preferences in a variety of taxa, but in many instances, single parameters are examined at a time. Furthermore, in species that use multimodal communication, there remain questions about whether a single sensory modality is sufficient to elicit such plasticity. In this study, we manipulated multiple parameters using vibratory playback to examine whether social experience during the brush-legged wolf spider's juvenile stage affected preferences for low- and high-amplitude signals as an adult. Ultimately, only the amplitude of the male's signals that they were exposed to as a juvenile impacted adult mate preference—not the number of perceived males or how often they encountered the males. These results, along with previous studies, demonstrate that S. ocreata is capable of plasticity in response to social cues in multiple modalities. [ABSTRACT FROM AUTHOR]

The gut microbiomes of arthropods have significant impact on key physiological functions such as nutrition, reproduction, behavior, and health. Spiders are diverse and numerically dominant predators in crop fields where they are potentially important regulators of pests. Harnessing spiders to control agricultural pests is likely to be supported by an understanding of their gut microbiomes, and the environmental drivers shaping microbiome assemblages. This study aimed to deciphering the gut microbiome assembly of these invertebrate predators and elucidating potential implications of key environmental constraints in this process. Here, we used high-throughput sequencing to examine for the first time how the assemblages of bacteria in the gut of spiders are shaped by environmental variables. Local drivers of microbiome composition were globally-relevant input use system (organic production vs. conventional practice), and crop identity (Chinese cabbage vs. cauliflower). Landscape-scale factors, proportion of forest and grassland, compositional diversity, and habitat edge density, also strongly affected gut microbiota. Specific bacterial taxa were enriched in gut of spiders sampled from different settings and seasons. These findings provide a comprehensive insight into composition and plasticity of spider gut microbiota. Understanding the temporal responses of specific microbiota could lead to innovative strategies development for boosting biological control services of predators.

Light availability is highly variable, yet predictable, over various timescales and is expected to play an important role in the evolution of visual signals. Courtship displays of the wolf spider genus Schizocosa always involve the use of substrate-borne vibrations; however, there is substantial variation in the presence and complexity of visual displays among species. To gain insight into the role the light environment plays in the evolution of courtship displays, we tested the function of visual courtship signaling across distinct light environments in four species of Schizocosa that vary in their degree of ornamentation and dynamic visual signals. We ran mating and courtship trials at three light intensities (bright, dim, and dark) and tested the hypothesis that ornamentation interacts with light environment. We also examined each species' circadian activity patterns. The effects of the light environment on courtship and mating varied between species, as did circadian activity patterns. Our results suggest that femur pigmentation may have evolved for diurnal signaling, whereas tibial brushes may function to increase signal efficacy under dim light. Additionally, we found evidence for light-dependent changes in selection on male traits, illustrating that short-term changes in light intensity have the potential for strong effects on the dynamics of sexual selection. [ABSTRACT FROM AUTHOR]

BACKGROUND: Understanding the networks of trophic interactions into which generalist predators are embedded is key to assessing their ecological role of in trophic networks and the biological control services they provide. The advent of affordable DNA metabarcoding approaches greatly facilitates quantitative understanding of trophic networks and their response to environmental drivers. Here, we examine how key environmental gradients interact to shape predation by Lycosidae in highly dynamic vegetable growing systems in China. RESULTS: For the sampled Lycosidae, crop identity, pesticide use and seasons shape the abundance of prey detected in spider guts. For the taxonomic richness of prey, local‐ and landscape‐scale factors gradients were more influential. Multivariate ordinations confirm that these crop‐abundant spiders dynamically adjust their diet to reflect environmental constraints and seasonal availability to prey. CONCLUSION: Plasticity in diet composition is likely to account for the persistence of spiders in relatively ephemeral brassica crops. Our findings provide further insights into the optimization of habitat management for predator‐based biological control practices. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

We tested lethal and sublethal effects of five commonly applied herbicides on the agrobiont wolf spider Pardosa milvina. Pardosa were collected from two agricultural fields; one kept under continuous crop rotation and sprayed for over twenty years, the other had no pesticide application for the last twelve years. Male and female Pardosa from each site were exposed to one of seven herbicide treatments (atrazine, glyphosate, mesotrione, S-metolachlor, rimsulfuron, a combination of all five herbicides, or a distilled water control; N = 1201) and maintained for 52 days on the treated soil substrate. We recorded mortality, prey capture behavior, weight change, courtship behavior, and egg sac production across treatments. Mesotrione and the five-herbicide combination showed significantly higher mortality than control substrates while atrazine, glyphosate and S-metolachlor showed significantly higher survival than the control. Both male spiders and spiders collected from the conventional field had reduced survival under some herbicide treatments. Prey capture behavior varied significantly by herbicide treatment, sex, and site. We observed significant weight change differences in males and differences in egg sac production in females, with, compared to the control, significant male weight loss in the rimsulfuron treatment collected from the no herbicide field, and a decrease in egg sac production in rimsulfuron and S-metolachlor treatments among females collected from the no herbicide field. Our results show some herbicides may have modest but significant fitness benefits (atrazine, glyphosate, and S-metolachlor) while others strongly increase the mortality of a generalist predator (mesotrione and the combination herbicide treatment). [ABSTRACT FROM AUTHOR]

Taxonomic findings from biodiversity hotspots are always fascinating because of their vulnerability. In this paper we are reporting Pardosa parathompsoni Wang & Zhang, 2014 for the first time from Western Ghats region of India along with additional information on cheliceral morphology. [ABSTRACT FROM AUTHOR]

Cannibalism is common in spiders. Wolf spider (Lycosidae) females, which exhibit extensive maternal care, have been reported to cannibalize less when they are carrying egg sacs and juveniles. In a laboratory experiment, we demonstrated that cannibalism of early‐instar spiderlings (EIS) by a wolf spider (Pardosa pseudoannulata) mother was almost completely inhibited when she was carrying spiderlings. Compared with virgin and mated‐females, mother spiders tolerated more and predated fewer spiderlings, including gregarious pulli and newly dispersed spiderlings (NDS). Cannibalism of EIS by females during their reproductive period exhibited a V‐shaped pattern, with a gradual decrease from the egg sac‐carrying to pulli‐carrying (PC) stage, and a recovery from the PC stage to post‐reproductive (PR) stage. Notably, there was 0 cannibalism at the PC stage. PC females exhibited no interest in pulli, while PR females were attracted to and predated pulli and NDS as they did their natural prey, Nilaparvata lugens. Interestingly, PC females captured and released NDS in a foraging assay, although attraction was observed from olfactometer measurements. PC mothers possessed a cuticular volatile profile that was closer to that of pulli and NDS than to that of PR females. Moreover, NDS cuticular extract provoked an electrophysiological response in legs of PC females. Therefore, cuticular compound‐mediated chemical communication may be involved in inhibiting cannibalism of EIS by spider mothers, and especially in eliminating cannibalism by PC mothers. Future studies will aim to characterize the specific cuticular compounds and chemoreception mechanism in females, which will facilitate our understanding of intraspecific recognition and cannibalism in spiders. [ABSTRACT FROM AUTHOR]

Three new species of spiders are described from different provinces in Iran: Shaitan angramainyu sp. n. (Gnaphosidae) related to Sh. elchini Kovblyuk, Kastrygina et Marusik, 2013 known from Azerbaijan to Kazakhstan, Piratula raika sp. n. (Lycosidae) related to P. logunovi Omelko, Marusik et Koponen, 2011 known from Eastern Siberia, and Orthobula mikhailovi Marusik, sp. n. (Trachelidae) related to the widespread O. charitonovi (Mikhailov, 1986). This is the first record of the previously monotypic genus Shaitan Kovblyuk, Kastrygina et Marusik, 2013 in Iran, as well as its southernmost known locality. All species, including the closely related ones, are illustrated.

Phenology of the wolf spider, Pardosa flavisterna, was studied. This species is an abundant arthropod predator in the agroecosystems of Kashmir valley and is restricted to some parts of India and Pakistan only. The life cycle pattern was deduced via sampling done by manual searching, pitfall trapping in 24 different agricultural fields, and individuals reared under laboratory conditions. Males and females underwent seven moultings to mature and showed a mean carapace width (± SEM) of 2.594 mm (± 0.026) n = 17, and 2.470 mm (± 0.040) n = 14, respectively, at maturity. Investigation of the monthly catches and outcome of the measurement of their carapace width indicated an annual-biannual life cycle of P. flavisterna having stenochronous occurrence, reproducing in spring and summer. Females produce two egg sacs. Individuals of the first brood overwinter as subadults, while the second brood overwinters as juveniles. The first brood matured in the upcoming spring, while the second brood matured the next spring after growing throughout the year. The mean clutch size (± SEM) is 68.24 (± 4.57), n = 122, range = 41–103 eggs. Weather parameters had an impact on the number of catches, with temperature showing a positive correlation, and rainfall and humidity showing a negative relationship with the number of individuals caught. A minimum of two size classes were recorded throughout the year as a result of this life cycle pattern. [ABSTRACT FROM AUTHOR]

While most research on sexual signals as indicators of health status and infection has been focused on communication by visual (color), airborne acoustic (song structure, amplitude, frequency, and pattern), or chemical means, new evidence suggests that substrate‐borne vibratory signals can also be a reliable indicator of male quality and possibly infection history. In this study, we investigated the ability of the vibratory cues in multimodal sexual signals of Schizocosa ocreata wolf spiders to convey male health information to a female, and whether females adjust their mate choice decisions based on these cues. Individual components of the complete vibratory signal, including stridulatory pulse rate, mean amplitude, and peak amplitude, were all significant predictors of mating success in live trials. Males infected as a juvenile (during the penultimate molt) had significantly lower stridulatory rate and peak amplitude than control males. There were no significant differences in any of the vibratory signal components between control males and males infected as adults (1 h prior to mating trials). This suggests that the vibratory cues in this species may be altered when infection occurs during development, allowing females to avoid males that have been immunocompromised in the past. However, these cues are not reliable indicators of whether a male is actively infected, which means that the evaluation of these cues will not help a female avoid contact with infected individuals. Taken together, these results suggest that vibratory signals may convey honest information about male quality and past health, allowing females to choose mates that have not been compromised during development. [ABSTRACT FROM AUTHOR]

Abstract As a key predator group, spiders have received a lot of attention by food web ecologists. The difficulty involved in studying their diet has led to the use of new technologies such as metabarcoding of gut contents. The amplification of a broad range of spider prey without amplifying spiders themselves is challenging. Until now, an efficient universal primer for this purpose was not available. We developed a novel forward primer (NoSpi2) targeting the COI gene. The primer was designed not to amplify spiders of Pardosa genus while amplifying most other invertebrates. NoSpi2 was tested together with the reverse primer BR2 in silico, in vitro on single specimens of prey and spiders, on mock and malaise trap communities, and in an ecological application. In silico evaluation predicted high primer bias for Pardosa species and more generally for spiders of the oval calamistrum clade (Lycosidae and closely related species) and low bias for other invertebrates. These results were confirmed by in vitro tests. Additionally, some spider families were not amplified contrary to our expectations. We demonstrated a high efficiency for the primer pair NoSpi2/BR2 which recovered 94% of taxa in the mock community and 85% of the taxa detected by the best invertebrate primer pair known for the malaise trap community. The field experiment showed that Lycosidae (Hygrolycosa, Pardosa, Piratula, Trochosa) DNA is not amplified by NoSpi2/BR2. It demonstrated a broad range of detectable prey species (12 orders, 67 families, 117 species). The ability of NoSpi2/BR2 primer to reliably amplify prey species, without amplifying any predator DNA, makes it an ideal choice for gut content analysis for lycosid species and related species, even enabling the homogenization of entire specimens without dissection. Given that the detected prey species included other spiders and carabid beetles, this primer could be also used to study intraguild predation.

Abstract As top consumers and generalist predators, spiders are ideal organisms to study food webs and complex ecological functions using stable isotopes. Most researchers use whole‐body samples to analyze stable isotope ratios in spiders. Spiders can regrow lost legs and produce multiple molts during a life cycle, and nonlethal sampling utilizing legs and molts may provide a useful alternative to whole‐body sampling especially in larger bodied or threatened species. Furthermore, removing spider abdomens and thus leftover prey in the gut contents may provide a more accurate isotopic value. We tested the hypothesis that the δ15N, δ13C, or δ2H isotopic values in spider legs are reliable proxies for spider prosomas, abdomens, or whole bodies. We used laboratory‐reared large‐bodied spiders (Pterinochilus murinus) and field‐collected Lycosidae to compare lethal and nonlethal tissue isotopic values. We found that nonlethal samples of spider legs and molts are acceptable alternatives to lethal whole‐body samples to determine δ13C and δ15N stable isotope signatures. Nonlethal samples are not suitable proxies for whole‐body samples to determine δ2H isotopic values. Using nonlethal leg or molts samples in stable isotope investigations of spiders will allow researchers to promote conservation efforts and study threatened species while ensuring accurate and repeatable results.

Males and females have conflicting interests on the frequency and outcomes of mating interactions. Males maximize their fitness by mating with as many females as possible, whereas choosy females often reduce receptivity following copulation. Alternative male mating tactics can be adaptive in their expression to a variety of mating contexts, including interactions with a relatively unreceptive mated female. Male Rabidosa punctulata wolf spiders can adopt distinctive mating tactics when interacting with a female, a complex courtship display, and/or a more coercive direct mount tactic that often involves grappling with females for copulation. In this study, we set up female mating treatments with initial trials and then paired mated and unmated females with males to observe both female remating frequencies and the male mating tactics used during the interactions. Males adopted different mating tactics depending on the mating status of the female they were paired with. Males were more likely to adopt a direct mount tactic with already-mated females and courtship with unmated females. Already-mated females were considerably less receptive to males during experimental trials, although they did remate 34% of the time, the majority of which were with males using a direct mount tactic. Whereas males adjusting to these contextual cues were able to gain more copulations, the observation of multiple mating in female R. punctulata introduces the potential for sperm competition. We discuss this sexual conflict in terms of the fitness consequences of these mating outcomes for both males and females. [ABSTRACT FROM AUTHOR]

Changing abiotic conditions can affect the phenology of animals and plants with implications for their reproductive output, especially in rapidly changing regions like the Arctic. For instance in arthropods, it was recently shown that females of the spider species Pardosa glacialis (Thorell 1872) (Lycosidae) are able to produce two clutches within one growing season in years when snowmelt occurs particularly early. This phenomenon could be widespread in northern latitudes, and here we investigated the voltinism of two other very abundant species of wolf spiders in the Low-Arctic, Pardosa hyperborea (Thorell 1872) and Pardosa furcifera (Thorell 1875), over the period 2015–2017. Whilst a bimodal pattern in the clutch size frequency distribution was only revealed for P. hyperborea, we were able to show that both species can produce a second clutch over the active season by using information on the embryonic stages. We also observed significantly larger first than second clutches. We argue that information about the embryonic stage can be critical for evaluating evidence of wolf spider populations producing more than one clutch in a season. Our study provides evidence that bivoltinism could be a more widespread pattern than expected in Arctic wolf spiders. It remains to be investigated what the trophic consequences of such patterns are in a global warming context. We thus highlight the need for a coordinated framework for such further studies, integrating and relating various functional traits. [ABSTRACT FROM AUTHOR]

Arthropods inhabiting floodplains have to cope with regular cycles of wet and dry conditions. Allocosa senex and Allocosa marindia are two sympatric and synchronic sand‐dwelling wolf spiders that construct burrows along South American coasts and are subject to periodic floods. Our objective was to study tolerance to immersion and describe the behavioral responses to that event in A. senex and A. marindia. We placed each spider in a terrarium with sand as substrate to allow burrow construction. Then, we gradually increased water levels and recorded the behavioral responses for 30 min. None of the individuals died during the artificial flood. More adults of A. senex performed "dives" and "floats" compared to A. marindia. Also, A. senex showed higher occurrences of "floats," "swims," and swam for longer than A. marindia. Finally, females of both species swam more frequently than males. Our findings indicate that both Allocosa are able to withstand floods, showing differential tactics according to the life histories of each sex and species. [ABSTRACT FROM AUTHOR]

As top consumers and generalist predators, spiders are ideal organisms to study food webs and complex ecological functions using stable isotopes. Most researchers use whole‐body samples to analyze stable isotope ratios in spiders. Spiders can regrow lost legs and produce multiple molts during a life cycle, and nonlethal sampling utilizing legs and molts may provide a useful alternative to whole‐body sampling especially in larger bodied or threatened species. Furthermore, removing spider abdomens and thus leftover prey in the gut contents may provide a more accurate isotopic value. We tested the hypothesis that the δ15N, δ13C, or δ2H isotopic values in spider legs are reliable proxies for spider prosomas, abdomens, or whole bodies. We used laboratory‐reared large‐bodied spiders (Pterinochilus murinus) and field‐collected Lycosidae to compare lethal and nonlethal tissue isotopic values. We found that nonlethal samples of spider legs and molts are acceptable alternatives to lethal whole‐body samples to determine δ13C and δ15N stable isotope signatures. Nonlethal samples are not suitable proxies for whole‐body samples to determine δ2H isotopic values. Using nonlethal leg or molts samples in stable isotope investigations of spiders will allow researchers to promote conservation efforts and study threatened species while ensuring accurate and repeatable results. [ABSTRACT FROM AUTHOR]

The use of pesticides for plague control in agroecosystems generates a threat to wildlife and a major problem for human health. Pesticide compounds are also an important source of water and atmosphere contamination. Although insecticides are effective on their target organisms, they often affect organisms that are not their target. The aim of the present study was to research the effects of 3 types of neurotoxic insecticides—a pyrethroid (cypermethrin), a neonicotinoid (imidacloprid), and an organophosphate (chlorpyrifos)—on behavioral and physiological parameters of Pardosa saltans spider (Lycosidae). Our study analyzed for the first time the exploratory behavior of the spider mothers in the presence of these 3 insecticides on their egg‐sacs and also on the ground. We also evaluated the oxidative stress effects on the juveniles hatched in the egg‐sac protected by silk in relation to variations in detoxification enzymes (catalase, glutathione reductase, superoxide dismutase, glutathione‐S‐transferase, and glutathione peroxidase) and lipid peroxidation (reactive oxygen species [ROS]). The results show that these insecticides are repellents for mothers (cypermethrin is the most repellent), and maternal behavior is modified after detection of an insecticide on their egg‐sac but mothers do not abandon their egg‐sacs. These neurotoxic insecticides affect the juveniles inside their egg‐sac. Cypermethrin and chlorpyrifos caused more oxidative stress in juveniles than did imidacloprid. The ROS generated by these insecticides seemed to be adequately eliminated by the juveniles' antioxidant systems. Environ Toxicol Chem 2021;40:2861–2873. © 2021 SETAC [ABSTRACT FROM AUTHOR]

Spider-derived peptides with insecticidal, antimicrobial and/or cytolytic activities, also known as spider venom antimicrobial peptides (AMPs), can be found in the venoms of RTA-clade spiders. They show translational potential as therapeutic leads. A set of 52 AMPs has been described in the Chinese wolf spider (Lycosa shansia), and many have been shown to exhibit antibacterial effects. Here we explored the potential to enhance their antimicrobial activity using bioengineering. We generated a panel of artificial derivatives of an A-family peptide and screened their activity against selected microbial pathogens, vertebrate cells and insects. In several cases, we increased the antimicrobial activity of the derivatives while retaining the low cytotoxicity of the parental molecule. Furthermore, we injected the peptides into adult Drosophila suzukii and found no evidence of insecticidal effects, confirming the low levels of toxicity. Our data therefore suggest that spider venom linear peptides naturally defend the venom gland against microbial colonization and can be modified into more potent antimicrobial agents that could help to battle infectious diseases in the future. [Display omitted] • Bioengineering of three derivatives of a natural Lycosa shansia short linear venom peptide. • Enhanced charge and/or hydrophobicity in the engineered peptides. • Bioengineered modifications translate into increased antimicrobial activity. • Retained low toxicity to insects and vertebrate cells. [ABSTRACT FROM AUTHOR]

Arthropods are a dominant component of biodiversity in terrestrial ecosystems. They are considered pest control agents and drive important ecosystem processes like nutrient cycling. However, such ecosystem effects of arthropods may depend on the environmental context influencing nutrition and behaviour. In the framework of a grassland plant diversity experiment (Jena Experiment), we used stable isotope and fatty acid analysis to investigate intraspecific variations in the diet of two of the most abundant predatory arthropods in grasslands: the ground beetle Harpalus rufipes and the wolf spider Trochosa ruricola. The results show that the diet of H. rufipes varied significantly with plant species diversity, consuming more plant material, probably seeds, at high diversity plots, and in the presence of grasses and small herbs. By contrast, in presence of legumes H. rufipes consumed more animal prey, presumably aphids and/or collembolans. Compared to H. rufipes, the diet of T. ruricola consisted of animal prey only and varied mainly with body size, with larger individuals occupying higher trophic position in the food web. Moreover, the diet of T. ruricola changed in response to summer flooding two months before sampling. Presumably, the availability of secondary decomposer prey as well as intraguild prey was increased in severely flooded plots. As both species are considered pest control agents, the results underline the importance of plant diversity and the composition of plant communities for biological pest control.

Epigeal spiders were collected in five lowland rainforest habitats of the Masako Reserve (Kisangani, RD Congo): primary forest (>200 y. old), old secondary forest (± 80 y.), young secondary forest (40 y.), old fallow (12 y.) and young fallow (5 y.). The density and spatial distribution of spider populations were estimated by means of nocturnal distance sampling performed in all habitats except young secondary forest, and by pitfall trapping, applied in all five habitats. The epigeal spiders of the Masako forest belong to 62 species in 25 families. The most frequent families are Ctenidae, Lycosidae, and Sparassidae in the distance samples, and Zodariidae, Salticidae, and Corinnidae in the pitfalls. The density of the Ctenidae increases in an ascending sequence from 0.007 ind. m-2 in young fallow to 0.103 ind. m-2 in primary forest. For Lycosidae the sequence is inversed. They are by far the most common in young fallow (0.028 ind. m-2) and virtually absent in primary forest. Typical forest spiders, absent from open habitats, are common in old fallow which means that after 12 years, the typical forest fauna is already re-established. Only the young fallow fauna is clearly different from that of the other habitats, which confirms the high resilience and recolonization potential of epigeal spiders. [ABSTRACT FROM AUTHOR]

Bu çalışmada Lycosidae familyası içerisinde yer alan Arctosa maculata (Hahn, 1822) türünün karyotip analizi ülkemizde ilk kez yapılmıştır. Kromozomların elde edilmesinde standart giemsa boyama yöntemi uygulanmıştır. Bu yöntem, gonadların elde edilmesi, hipotonik uygulama, fiksasyon ve boyama olmak üzere dört ana basamak içermektedir. Çalışmada türe ait diploid kromozom sayısı 2n♂=28 olarak tespit edilmiştir. Eşey kromozomu sistemi X1X20 olup; tüm kromozomlar telosentrik tiptedir. Otozomal kromozomların relatif uzunluklarının kademeli olarak bir azalış gösterdiği kaydedilmiştir. Eşey kromozomlarının mayoz I evrelerinde pozitif heteropiknotik özellikte, mayoz II evrelerinde ise izopiknotik özellikte oldukları belirlenmiştir. [ABSTRACT FROM AUTHOR]

Pardosa is the largest genus in family Lycosidae. Many of the members in this family and genus show morphological similarity and intra-specific variation, which makes their taxonomy difficult. The conclusive method of genitalic analysis was limited in olden days might have resulted in misplacement of various taxa. In this paper, Pardosa mysorensis (Tikader & Mukerji, 1971) is synonymized with Pardosa sumatrana (Thorell, 1890) based on examination of specimen from southern Indian state of Kerala. Detailed genitalic photographs and habitus images are given. [ABSTRACT FROM AUTHOR]