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Aim: Long‐standing theory predicts that the intensity of biotic interactions increases from high to low latitudes. Studies addressing geographic variation in predation on insect prey have often relied on prey models, which lack many characteristics of live prey. Our goals were to explore global latitudinal patterns of predator attack rates on standardised live insect prey and to compare the patterns in predation on live insects with those on plasticine prey models. Location: Global forested areas. Time Period: 2021–2023. Major Taxa: Arthropods, birds. Methods: We measured predation rates in 43 forested locations distributed across five continents from 34.1° S to 69.5° N latitude. At each location, we exposed 20 sets of three bait types, one set per tree. Each set included three live fly larvae (maggots), three live fly puparia and three plasticine models of the puparia. We used glue rings to isolate half of the sets from non‐flying predators. Results: Arthropod attack rates on plasticine prey decreased linearly from low to high latitudes, whereas attack rates on maggots had a U shaped distribution, with the lowest predation rates at temperate latitudes and the highest rates at tropical and boreal latitudes. This difference emerged from intensive predator attacks on live maggots, but not on plasticine models, in boreal sites. Site‐specific attack rates of arthropod predators on live and plasticine prey were not correlated. In contrast, bird attack rates on live maggots and plasticine models were positively correlated, but did not show significant latitudinal changes. Main Conclusions: Latitudinal patterns in predation differ between major groups of predators and between types of prey. Poleward decreases in both arthropod and combined arthropod and bird predation on plasticine models do not mirror patterns of predation on our live prey, the latter likely reflecting real patterns of predation risk better than do patterns of attack on artificial prey. [ABSTRACT FROM AUTHOR]

In arthropods, hematophagy has arisen several times throughout evolution. This specialized feeding behavior offered a highly nutritious diet obtained during blood feeds. On the other hand, blood‐sucking arthropods must overcome problems brought on by blood intake and digestion. Host blood complement acts on the bite site and is still active after ingestion, so complement activation is a potential threat to the host's skin feeding environment and to the arthropod gut enterocytes. During evolution, blood‐sucking arthropods have selected, either in their saliva or gut, anticomplement molecules that inactivate host blood complement. This review presents an overview of the complement system and discusses the arthropod's salivary and gut anticomplement molecules studied to date, exploring their mechanism of action and other aspects related to the arthropod–host–pathogen interface. The possible therapeutic applications of arthropod's anticomplement molecules are also discussed. [ABSTRACT FROM AUTHOR]

Insectivorous predators, including birds and bats, play crucial roles in trophic cascades. However, previous research on these cascades has often relied on permanent predator exclosures, which prevent the isolation of specific effects of birds and bats, given their different activity patterns throughout the day. Moreover, limited knowledge exists regarding the variations in individual effects of these predators under different biotic and abiotic conditions, such as changes in elevation. To address these uncertainties, our study aimed to investigate the distinct effects of bats and birds on arthropod densities in foliage and herbivory damage in lowland and highland rainforests of Papua New Guinea (PNG). Predator exclosures were established for one month to exclude diurnal or nocturnal predators across 120 saplings (ca. 2.5–4 m tall) selected from two lowland and two highland forests (i.e., 30 saplings per study site) along the Mt. Wilhelm transect in PNG. Arthropods were collected and measured, and herbivory damage was analyzed at the end of the experiment. Birds significantly reduced arthropod densities by 30%, particularly in arthropods longer than 10 mm, regardless of elevation. Additionally, both birds and bats appeared to mitigate herbivory damage in highland forests, with protected saplings displaying up to 189% more herbivory. Our results support previous studies that have demonstrated the ability of insectivorous predators to reduce leaf damage through the control of arthropods. Furthermore, our approach highlights the importance and necessity of further research on the role of seasons and elevations in trophic cascades. [ABSTRACT FROM AUTHOR]

Head segments play a critical role in revealing the relationships within major arthropod groups but the accurate determination of their number and relationship is challenging because of the decoupling of dorsal tergites and ventral appendages. In recent decades, trilobites have been considered to have four pairs of cephalic appendages and, commonly, five dorsal segments, which has served as the basis for understanding euarthropod cephalic evolution. Based on multiple analytical techniques applied to well‐preserved soft‐bodied specimens of the Upper Ordovician olenid Triarthrus eatoni and middle Cambrian corynexochid Olenoides serratus, we argue that an additional pair of cephalic biramous appendages occurred just behind the antennae, indicating that trilobites had five pairs of cephalic appendages and six dorsally expressed segments. We propose that the mismatch between the four dorsal furrows and five ventral appendages in Olenoides may be reconciled by considering the morphology of the hypostome that marks the position of the antenna and the bifurcation of the first glabellar furrow that has two muscle attachment sites fused. The fusion of clustered attachment sites of the cephalic biramous appendages may have aided feeding ability by gathering the limb bases close to the mouth. [ABSTRACT FROM AUTHOR]

The attractive effect of dung on coprophagous beetle communities and their role in dung degradation are well‐known phenomena. However, little research has been conducted on the recruitment capacity of this substrate for other arthropods, especially those inhabiting the soil. With the aim of beginning to recognize general patterns in these relationships, the influence of the structure and origin of dung from invasive exotic mammals on the recruitment of microarthropods was investigated in two meadows within Nahuel Huapi National Park in southwestern Argentina. Abundance, richness and diversity of microarthropod communities collected on invasive mammal dung were studied. A total of 2478 microarthropods were collected and 52 species were identified. Recruitment of microarthropods on dung of two invasive coprophagic herbivores, the rabbit, Oryctolagus cuniculus and the hare, Lepus europaeus, were compared with two invasive non‐coprophagic mammals, one herbivorous, the red deer, Cervus elaphus and one omnivorous, the wild boar, Sus scrofa. Pellets of S. scrofa showed the highest microarthropod abundance and richness while diversity was greatest on pellets of C. elaphus. Pygmephorid and oribatid mites and springtails were the most abundant. Liposcelis psocopterans and oribatid mites were more abundant on S. scrofa dung. Low similarity was observed when comparing dung of invasive mammals from different sites revealing spatial variability regarding species composition. Based on its more diverse diet, we conclude that S. scrofa dung exerts a strong influence on microarthropod communities by recruiting a greater number of individuals and species than the dung of the remaining invasive mammals. [ABSTRACT FROM AUTHOR]

Recent losses in the abundance and diversity of arthropods have been documented in many regions and ecosystems. In grasslands, such insect declines are largely attributed to land use, including modern machinery and mowing regimes. However, the effects of different mowing techniques on arthropods remain poorly understood. Using 11 years of data from 111 agricultural grassland plots across Germany, we analyzed the influence of various grassland management variables on the abundance and abundance‐accounted species richness of four arthropod orders: Araneae, Coleoptera, Hemiptera, and Orthoptera. The analysis focused on detailed mowing information, for example, days after mowing and mower type, and compared their effect with other aspects of grassland management, that is, rolling, leveling, fertilization, and grazing. We found strong negative effects of mowing on all four arthropod orders, with arthropod abundance being lowest directly after mowing and steadily increasing to three to seven times the abundance after 100 days post‐mowing. Likewise, Hemiptera and Coleoptera species richness was 30% higher 100 days after mowing. Mower width showed a positive effect on Orthoptera abundance, but not on the other arthropods. Arthropod abundance and Coleoptera species richness were lowest when a mulcher was used compared to rotary or bar mowers. In addition to mowing, intensive grazing negatively affected Orthoptera abundance but not the other orders. Mowing represents a highly disturbing and iterative stressor with negative effects on arthropod abundance and diversity, likely contributed by mowing‐induced mortality and habitat alteration. While modifications of mowing techniques such as mower type or mowing height and width may help to reduce the negative impact of mowing on arthropods, our results show that mowing itself has the most substantial negative effect. Based on our results, we suggest that reduced mowing frequency, omission of mowing in parts of the grassland (refuges), or extensive grazing instead of mowing have the greatest potential to promote arthropod populations. [ABSTRACT FROM AUTHOR]

Vast grassland areas disappear due to abandonment, conversion to arable fields or urban areas. Consequently, grassland species have declined dramatically during and since the last century. The majority of remaining European grasslands are managed, many of them by mowing, which, in general, decreases arthropods' abundance and species richness.Here, we aimed to study the effects of width and proportion of refuge areas on local abundance and richness of arthropods in hay meadows. Within a ca. 4000 ha semi‐natural grassland area of the Great Hungarian Plain, we established refuge strips of different widths (3 and 9 m) and proportion of total field area (10 and 25%) following a randomised block design with six replicates per treatment. We studied five arthropod groups (grasshoppers, true bugs, carabids and ground‐dwelling and vegetation‐dwelling spiders), which we sampled 2 weeks after mowing by sweep netting and pitfall traps.Uncut strips were warmer and moister than the mown areas. The effects of refuge strips and their arrangement were stronger on the vegetation‐dwelling than on ground‐dwelling arthropods, although all taxa were affected in some way. We found more true bugs in mown areas between narrow strips than between wide strips. The interaction effect of width and proportion of refuge strips on the abundance of grasshoppers, ground‐dwelling spiders and species richness of carabids showed that wider strips are more beneficial if their proportion is low and narrow strips are more beneficial with high proportion.Synthesis and applications: Our findings provide evidence that uncut refuge strips can harbour diverse and abundant arthropod assemblages in hay meadows and mitigate the adverse effects of uniformly executed mowing on arthropods. Modifying attributes and considering farming practices, wide strips with a low (10%) proportion of total field area seem optimal for both conservation and practitioners. [ABSTRACT FROM AUTHOR]

Ultraviolet radiation (UVR) has positive and negative impacts on organisms and affects entire ecosystems. It is currently receiving attention because of the interactions of UVR with changes in climate that are likely to affect agriculture and food security.A review is provided on the effects of different types of UVR on the survival, development and reproduction of insects, collembolans and mites. The foci are on how UVR is used in pest control and how it affects arthropod coloration and distribution.Direct exposure to UV‐A, UV‐B and UV‐C delays development and reduces survival and host‐seeking ability of arthropods; immature stages are more sensitive than the adults. Increased exposure of crops to UVR has indirect effects on herbivory, and regions with high UVR levels may permit crop production in the absence of certain pest insect species.The Bunsen‐Roscoe law of reciprocity was upheld for Diaphorina citri and Tetranychus urticae under the range of irradiances and durations of exposure used in two studies, which showed that, for a constant dose, the effects of low irradiances of long durations were equivalent to those of higher irradiances of shorter durations.DNA damage caused by UV‐C and UV‐B can be repaired by photoreactivation; both white light and UV‐A are effective. [ABSTRACT FROM AUTHOR]

ABSTRACT Exoskeletons are a defining character of all arthropods that provide physical support for their segmented bodies and appendages as well as protection from the environment and predation. This ubiquitous yet evolutionarily variable feature has been instrumental in facilitating the adoption of a variety of lifestyles and the exploitation of ecological niches across all environments. Throughout the radiation that produced the more than one million described modern species, adaptability afforded by segmentation and exoskeletons has led to a diversity that is unrivalled amongst animals. However, because of the limited extensibility of exoskeleton chitin and cuticle components, they must be periodically shed and replaced with new larger ones, notably to accommodate the growing individuals encased within. Therefore, arthropods grow discontinuously by undergoing periodic moulting events, which follow a series of steps from the preparatory pre‐moult phase to ecdysis itself and post‐moult maturation of new exoskeletons. Each event represents a particularly vulnerable period in an arthropod's life cycle, so processes must be tightly regulated and meticulously executed to ensure successful transitions for normal growth and development. Decades of research in representative arthropods provide a foundation of understanding of the mechanisms involved. Building on this, studies continue to develop and test hypotheses on the presence and function of molecular components, including neuropeptides, hormones, and receptors, as well as the so‐called early, late, and fate genes, across arthropod diversity. Here, we review the literature to develop a comprehensive overview of the status of accumulated knowledge of the genetic toolkit governing arthropod moulting. From biosynthesis and regulation of ecdysteroid and sesquiterpenoid hormones, to factors involved in hormonal stimulation responses and exoskeleton remodelling, we identify commonalities and differences, as well as highlighting major knowledge gaps, across arthropod groups. We examine the available evidence supporting current models of how components operate together to prepare for, execute, and recover from ecdysis, comparing reports from Chelicerata, Myriapoda, Crustacea, and Hexapoda. Evidence is generally highly taxonomically imbalanced, with most reports based on insect study systems. Biases are also evident in research on different moulting phases and processes, with the early triggers and late effectors generally being the least well explored. Our synthesis contrasts knowledge based on reported observations with reasonably plausible assumptions given current taxonomic sampling, and exposes weak assumptions or major gaps that need addressing. Encouragingly, advances in genomics are driving a diversification of tractable study systems by facilitating the cataloguing of putative genetic toolkits in previously under‐explored taxa. Analysis of genome and transcriptome data supported by experimental investigations have validated the presence of an “ultra‐conserved” core of arthropod genes involved in moulting processes. The molecular machinery has likely evolved with elaborations on this conserved pathway backbone, but more taxonomic exploration is needed to characterise lineage‐specific changes and novelties. Furthermore, linking these to transformative innovations in moulting processes across Arthropoda remains hampered by knowledge gaps and hypotheses based on untested assumptions. Promisingly however, emerging from the synthesis is a framework that highlights research avenues from the underlying genetics to the dynamic molecular biology through to the complex physiology of moulting. [ABSTRACT FROM AUTHOR]

Endosymbionts are widespread in arthropods, living in host cells with effects that extend from parasitic to mutualistic. Newly acquired endosymbionts tend to be parasitic, but vertical transmission favors coevolution toward mutualism, with hosts sometimes developing dependency. Endosymbionts negatively affecting host fitness may still spread by impacting host reproductive traits, referred to as reproductive "manipulation," although costs for hosts are often assumed rather than demonstrated. For cytoplasmic incompatibility (CI) that involves endosymbiont‐mediated embryo death, theory predicts directional shifts away from "manipulation" toward reduced CI strength; moreover, CI‐causing endosymbionts need to increase host fitness to initially spread. In nature, endosymbiont–host interactions and dynamics are complex, often depending on environmental conditions and evolutionary history. We advocate for capturing this complexity through appropriate datasets, rather than relying on terms like "manipulation." Such imprecision can lead to the misclassification of endosymbionts along the parasitism–mutualism continuum. [ABSTRACT FROM AUTHOR]

Forest ecosystems are facing increasing challenges like natural disturbances. Despite positive disturbance impacts on the diversity of several taxonomic groups, there are still concerns, whether the drastic canopy opening can lead to a turnover from forest to open habitat species.We sampled arthropods along a disturbance gradient in Norway spruce (Picea abies)‐dominated protected areas across Central Europe using Malaise traps and metabarcoding.To analyse changes in arthropod communities in terms of forest affinities along the disturbance gradient, we explored the potential of a list of forest affinities (LFA) that provides information about species affinities from closed forest to open habitats.Our results show that the mean forest affinity decreased with increasing disturbance severity. This trend was accompanied by a decrease in forest‐associated species as well as community shifts for open and mixed habitat species. Responses varied between taxa and were most apparent in Coleoptera.Overall, the changes did not come with a complete replacement of forest specialists by species with higher affinities for mixed and open landscapes nor a drastic loss of forest species. Furthermore, we observed severely disturbed plots with a high mean forest affinity and vice versa, which calls for further studies using these kinds of species classifications.The LFA can provide additional information how species associated with forests habitats can react to environmental changes beyond increasing amounts of deadwood resources. Using additional trapping methods and determination techniques might increase the explanatory power of such analyses along ecological gradients. [ABSTRACT FROM AUTHOR]

Restoring the heterogeneity of farmland mosaics can help mitigate the ongoing global decline of biodiversity. It has been shown that semi‐natural habitats in viticultural landscapes influence biodiversity in vineyards. However, less attention has been paid to the influence of the extent of vineyard fields and their arrangement in the landscape.Using previously published data, we investigated the influence of both semi‐natural habitats and vineyard fields on arthropod diversity in vineyards in 35 viticultural landscapes located in South Africa and Austria. Effects on several arthropod groups were assessed using standardised landscape predictors that integrate compositional (total area) and configurational (shape and spatial arrangement) heterogeneity of semi‐natural habitats and vineyards. In addition, we assessed the influence of within‐vineyard vegetation cover and farming system (organic or non‐organic) to explore local‐scale effects.Within‐vineyard vegetation and flower cover had a consistent positive influence on most arthropod taxa, whereas farming system had little effect. In addition, configurational heterogeneity of semi‐natural vegetation and vineyards influenced several taxa. However, different taxa showed contrasting relationships with configurational heterogeneity, hindering general recommendations for optimal configuration of semi‐natural elements and vineyards in the landscape. The only significant response to compositional heterogeneity was bug abundance in South Africa, which increased with increasing proportion of semi‐natural elements.We found that increasing vegetation cover in vineyards is an effective and easily implementable measure to improve biodiversity in vineyards. In addition, the spatial arrangement of vineyards influences within‐vineyard arthropod diversity as much as the spatial arrangement of semi‐natural vegetation in the landscape, which expands the possibilities for planning viticultural landscapes with high overall biodiversity. [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]

Synthetic studies of arthropod systematics and biodiversity are hindered by overreliance on 'preferred' semaphoronts, those life stages (typically adult males) that provide the most taxonomically distinctive characters. However, modern sequence‐based methods for inventory have no such limitations and permit incorporation of any and all representatives of a species. Here, we briefly review the growth and potential of these approaches to faunistic and systematic studies and share results from our own recent work that illustrate the value that other morphs, immature stages and females added to these studies. [ABSTRACT FROM AUTHOR]

The temporal dynamics of insect populations in agroecosystems are influenced by numerous biotic and abiotic interactions, including trophic interactions in complex food webs. Predicting the regulation of herbivorous insect pests by arthropod predators and parasitoids would allow for rendering crop production less dependent on chemical pesticides.Curtsdotter et al. (2019) developed a food‐web model simulating the influences of naturally occurring arthropod predators on aphid population dynamics in cereal crop fields. The use of an allometric hypothesis based on the relative body masses of the prey and various predator guilds reduced the number of estimated parameters to just five, albeit field‐specific.Here, we extend this model and test its applicability and predictive capacity. We first parameterized the original model with a dataset with the dynamic arthropod community compositions in 54 fields in six regions in France. We then integrated three additional biological functions to the model: parasitism, aphid carrying capacity and suboptimal high temperatures that reduce aphid growth rates. We developed a multi‐field calibration approach to estimate a single set of generic allometric parameters for a given group of fields, which would increase model generality needed for predictions.The original and revised models, when using field‐specific parameterization, achieved quantitatively good fits to observed aphid population dynamics for 59% and 53% of the fields, respectively, with pseudo‐R2 up to 0.99. But the multi‐field calibration showed that increased model generality came at the cost of reduced model reliability (goodness‐of‐fit).Our study highlights the need to further improve our understanding of how body size and other traits affect trophic interactions in food webs. It also points up the need to acquire high‐resolution data to use this type of modelling approach. We propose that a hypothesis‐driven strategy of model improvement based on the integration of additional biological functions and additional functional traits beyond body size (e.g., predator space search or prey defences) into the food‐web matrix can improve model reliability. [ABSTRACT FROM AUTHOR]

Symbiotic relationships shape ecological communities and often involve more than two species. Yet few experimental studies examine the impact of symbioses involving three species, particularly any mediating role of third parties, and none involving symbioses of predators.We investigated experimentally the synergistic and antagonistic fitness effects of three symbiotic spider predators across a broad latitudinal range and involving different species combinations.The three‐dimensional web complex of Cyrtophora spiders is a habitat patch to different associates—species of Argyrodes and web‐building Leucauge spider guests. Our field experiments, which manipulated the presence of each guest species and determined the subsequent host weight change, revealed a remarkable consistency in fitness outcomes across the three populations, with the consequences of the interactions between two species depending upon the services provided by a third.Cyrtophora hosts intercepted more prey when web‐building Leucauge guests were present and thus gained more weight. In contrast, Argyrodes guests exerted a fitness cost on their Cyrtophora host, but only when Leucauge guests were absent. A comparison of the prey consumed by Cyrtophora hosts and Argyrodes guests revealed that their diets (reflected in the size of prey) overlapped less in the presence of Leucauge web‐building guests.Our novel experimental study highlights the importance of exploring synergistic effects in multi‐species symbioses. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The Arctic is impacted by some of the fastest temperature changes observed on Earth, but the impact on the terrestrial arthropod fauna is unclear. Acute physiological thermal limits of terrestrial ectotherms from high latitudes often exceed the local air temperatures, suggesting that they may be able to cope with increasing temperatures. However, knowledge on how Arctic terrestrial arthropods cope with elevated temperatures for longer periods is lacking.Here we investigate how acclimation temperature and exposure time affect the acute physiological heat tolerance of five terrestrial arthropod species (Neomolgus littoralis, Megaphorura arctica, Nysius groenlandicus, Psammotettix lividellus and Nabis flavomarginatus) immediately after collection in Arctic and sub‐Arctic habitats.We show that although acute heat tolerances are relatively high, even exposure to moderate (temperature span assessed ca. 3–29°C) acclimation temperatures for a 24 h period have strong negative effects on heat tolerance for four of the five species. Similarly, exposure time negatively affected heat tolerance, but depending on species and temperature.Together our results suggest that exposure to even moderately elevated temperatures for periods of 24 h or even shorter can lead to lower acute heat tolerance for cold adapted terrestrial arthropod species from sub‐Arctic and Arctic regions. Consequently, climate change leading to extended periods of mildly elevated temperatures may have strong negative effects on these species. We argue that this aspect is currently overlooked when assessing the ability of arthropods from Arctic and sub‐Artic regions to cope with climate changes as such predictions are typically based on acute heat tolerance estimates and with the assumption of beneficial acclimation responses. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

C‐type lectins (CTLs) are a family of proteins that contain 1 or more carbohydrate‐recognition domains (CRDs) and bind to a broad repertoire of ligands in the presence of calcium ions. CTLs play important roles in innate immune defenses against microorganisms by acting as pattern‐recognition receptors (PRRs) for invading pathogens, such as bacteria, viruses, and parasites. After binding to pathogen‐associated ligands, CTLs mediate immune responses, such as agglutination, phagocytosis, and the activation of phenol oxidase progenitors, thereby clearing pathogens. CTLs are an evolutionarily conserved family found in almost all vertebrates and invertebrates. Medical arthropods can acquire and transmit a range pathogens through various approaches, such as bloodsucking, lancing, and parasitism, thus infecting humans and animals with related diseases, some of which can be life‐threatening. Recent studies have shown that lectins are important components of the arthropod immune system and are essential for the immune responses of arthropods to arthropod‐borne pathogens. This article reviews the current understanding of the structure, function, and signaling pathways involved in CTLs derived from important medical arthropods. [ABSTRACT FROM AUTHOR]

In North America, white‐nose syndrome (WNS) has caused precipitous declines in hibernating bat populations, raising the question of whether the rapid loss of arthropodivorous bats may affect the abundance of their prey. During the summers of 2015–2018 (1 year after the arrival of WNS in Wisconsin, USA), we performed intensive arthropod black‐light trapping, ultrasonic acoustic monitoring, and emergence counts at 10 little brown (Myotis lucifugus) and big brown (Eptesicus fuscus) bat maternity roosts with paired control sites. For little brown bats, which are severely affected by WNS, roost counts declined by 95% over the four‐year period, compared to a 38% decline in big brown bat roost counts. Total arthropod abundance decreased by 49%, although decreases among common little brown bat prey were less severe. Our natural predator exclusion experiment supports existing evidence that bats can have measurable trophic impacts on arthropod communities, primarily via top‐down effects on common prey. [ABSTRACT FROM AUTHOR]

Seasonally abundant arthropods are a crucial food source for many migratory birds that breed in the Arctic. In cold environments, the growth and emergence of arthropods are particularly tied to temperature. Thus, the phenology of arthropods is anticipated to undergo a rapid change in response to a warming climate, potentially leading to a trophic mismatch between migratory insectivorous birds and their prey. Using data from 19 sites spanning a wide temperature gradient from the Subarctic to the High Arctic, we investigated the effects of temperature on the phenology and biomass of arthropods available to shorebirds during their short breeding season at high latitudes. We hypothesized that prolonged exposure to warmer summer temperatures would generate earlier peaks in arthropod biomass, as well as higher peak and seasonal biomass. Across the temperature gradient encompassed by our study sites (>10°C in average summer temperatures), we found a 3‐day shift in average peak date for every increment of 80 cumulative thawing degree‐days. Interestingly, we found a linear relationship between temperature and arthropod biomass only below temperature thresholds. Higher temperatures were associated with higher peak and seasonal biomass below 106 and 177 cumulative thawing degree‐days, respectively, between June 5 and July 15. Beyond these thresholds, no relationship was observed between temperature and arthropod biomass. Our results suggest that prolonged exposure to elevated temperatures can positively influence prey availability for some arctic birds. This positive effect could, in part, stem from changes in arthropod assemblages and may reduce the risk of trophic mismatch. [ABSTRACT FROM AUTHOR]

Herbivorous arthropods can induce their host to form structures where they shelter during unfavourable periods. The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), can spend the off‐season inside cotton plant structures, known as dry bolls, protected from pesticides, natural enemies and heat and desiccation on the soil surface, thereby increasing its survival and preserving its reproductive capacity. However, the relationship between the boll weevil and dry boll formation is not fully understood and requires further study. The formation and external and internal characteristics of dry bolls on cotton plants infested with different densities of boll weevils, and the emergence and survival of this insect from these structures, were evaluated. Compared with non‐infested control plants, plants infested with boll weevil formed almost twice as many dry bolls, which were 2.3 times heavier and with a diameter 1.7 times larger than those on non‐infested plants. Boll weevil infestation reduces the number of bolls and commercial mass of fibre + seeds, reducing productivity and increasing cotton harvest contaminants. However, dry bolls on non‐infested plants demonstrate that other factors are involved in their formation. [ABSTRACT FROM AUTHOR]

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Multi‐decadal monitoring has revealed dramatic evidence of global decline in arthropod biomass and biodiversity, yet little baseline information exists for Alaska, a region 1/5th the size of the contiguous US states. We documented patterns of aerial arthropod biomass and diversity in a multi‐year investigation of three regions in boreal Alaska—two in central Alaska (Fairbanks and Tetlin) and one in southcentral Alaska (Anchorage). Sampling employed canopy Malaise and near‐ground pollinator traps as part of a parallel study of a steeply declining songbird. Traps yielded 115,078 specimens of 15 orders and 692 unique taxa with body sizes ≥3 mm. During peak summer (15 June–15 July), mean aerial arthropod biomass was more than three times higher in traps in Fairbanks (50.6 mg·d−1, confidence interval [CI]: 34.5–63.7) than Anchorage (15.8 mg·d−1, CI: 9.3–26.4). Tetlin exhibited an intermediate value (35.4 mg·d−1, CI: 18.4–67.4). Temperature correlated positively with captured biomass, whereas wind (above 1.5 m·s−1) correlated negatively. To obtain species‐level diversity data, we focused on beetles, representing a wide range of feeding guilds and taxa. Beetles accounted for 6229 adult specimens, 364 unique (mostly species‐level) taxa and 47 families. Trophic categorizations of beetles were similar for the central Alaskan sites; both had a greater proportion of wood‐feeding beetles than Anchorage. Ten species are potentially new to science and 49 are new state records for Alaska. Our work provides the first insight into regional differences and seasonal trends in aerial arthropod biomass and diversity in boreal Alaska, creating important baselines for the future. [ABSTRACT FROM AUTHOR]

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

Soybean aphid (Aphis glycines) insecticides are used throughout the Upper Midwest and Great Plains regions of North America, including the farmland region of Minnesota, USA, to combat insect pests. These broad‐spectrum, foliar spray insecticides have the potential to drift beyond target fields into nearby grassland cover where birds and other insectivores forage. Arthropods serve important roles in grassland ecology and are susceptible to mortality and sublethal effects from exposure to these pesticides. Our objective was to assess effects of soybean aphid insecticides on grassland arthropods, especially those that are important in grassland bird diets. We measured the abundance, consumable biomass, and family richness of insects and spiders in grasslands adjacent to soybean fields in an agricultural landscape. Soybean fields were treated with chlorpyrifos and lambda‐cyhalothrin, which were the 2 most common foliar pesticides used to control soybean aphids in Minnesota. We compared measures at focal sites to samples collected at reference sites adjacent to corn fields not sprayed for aphids during 3 periods in mid‐to‐late summer: 1–3 days before spraying, 3–5 days post‐spraying, and 19–21 days post‐spraying. The abundance of arthropods in focal grasslands was lower 3–5 days after pesticide applications. Coleoptera family richness at focal sites was also lower than at reference sites 3–5 days after pesticide applications. These measures 19–21 days after application were similar to pre‐spraying levels, indicating that arthropod populations rebounded during this period. Measures of consumable dry biomass, bird prey abundance, bird prey biomass, family richness of Araneae, family richness of Hemiptera, and family richness of Orthoptera were not different between focal and reference sites after spraying. Our results reveal that reductions in arthropod food abundance for grassland birds are associated with pesticide applications up to 5 days after spraying. We suggest that natural resource managers factor proximity to row crop fields and susceptibility to pesticide drift into decisions about where to add grassland cover to landscapes. [ABSTRACT FROM AUTHOR]

Summary: Community genetics seeks to understand the mechanisms by which natural genetic variation in heritable host phenotypes can encompass assemblages of organisms such as bacteria, fungi, and many animals including arthropods. Prior studies that focused on plant genotypes have been unable to identify genes controlling community composition, a necessary step to predict ecosystem structure and function as underlying genes shift within plant populations.We surveyed arthropods within an association population of Populus trichocarpa in three common gardens to discover plant genes that contributed to arthropod community composition. We analyzed our surveys with traditional single‐trait genome‐wide association analysis (GWAS), multitrait GWAS, and functional networks built from a diverse set of plant phenotypes.Plant genotype was influential in structuring arthropod community composition among several garden sites. Candidate genes important for higher level organization of arthropod communities had broadly applicable functions, such as terpenoid biosynthesis and production of dsRNA binding proteins and protein kinases, which may be capable of targeting multiple arthropod species.We have demonstrated the ability to detect, in an uncontrolled environment, individual genes that are associated with the community assemblage of arthropods on a host plant, further enhancing our understanding of genetic mechanisms that impact ecosystem structure. [ABSTRACT FROM AUTHOR]

Tree diversity can promote both predator abundance and diversity. However, whether this translates into increased predation and top‐down control of herbivores across predator taxonomic groups and contrasting environmental conditions remains unresolved. We used a global network of tree diversity experiments (TreeDivNet) spread across three continents and three biomes to test the effects of tree species richness on predation across varying climatic conditions of temperature and precipitation. We recorded bird and arthropod predation attempts on plasticine caterpillars in monocultures and tree species mixtures. Both tree species richness and temperature increased predation by birds but not by arthropods. Furthermore, the effects of tree species richness on predation were consistent across the studied climatic gradient. Our findings provide evidence that tree diversity strengthens top‐down control of insect herbivores by birds, underscoring the need to implement conservation strategies that safeguard tree diversity to sustain ecosystem services provided by natural enemies in forests. [ABSTRACT FROM AUTHOR]

Species interact in different ways, including competition, facilitation and predation. These interactions can be non‐linear or higher order and may depend on time or species densities. Although these higher‐order interactions are virtually ubiquitous, they remain poorly understood, as they are challenging both theoretically and empirically. We propose to adapt niche and fitness differences from modern coexistence theory and apply them to species interactions over time. As such, they may not merely inform about coexistence, but provide a deeper understanding of how species interactions change. Here, we investigated how the exploitation of a biotic resource (plant) by phytophagous arthropods affects their interactions. We performed monoculture and competition experiments to fit a generalized additive mixed model to the empirical data, which allowed us to calculate niche and fitness differences. We found that species switch between different types of interactions over time, including intra‐ and interspecific facilitation, and strong and weak competition. [ABSTRACT FROM AUTHOR]

Understanding how anthropogenic activities induce changes in the functional traits of arthropod communities is critical to assessing their ecological consequences. However, we largely lack comprehensive assessments of the long‐term impact of global‐change drivers on the trait composition of arthropod communities across a large number of species and sites. This knowledge gap critically hampers our ability to predict human‐driven impacts on communities and ecosystems.Here, we use a dataset of 1.73 million individuals from 877 species to study how four functionally important traits of carabid beetles and spiders (i.e. body size, duration of activity period, tolerance to drought, and dispersal capacity) have changed at the community level across ~40 years in different types of land use and as a consequence of land use changes (that is, urbanisation and loss of woody vegetation) at the landscape scale in Switzerland.The results show that the mean body size in carabid communities declined in all types of land use, with particularly stronger declines in croplands compared to forests. Furthermore, the length of the activity period and the tolerance to drought of spider communities decreased in most land use types. The average body size of carabid communities in landscapes with increased urbanisation in the last ~40 years tended to decrease. However, the length of the activity period, the tolerance to drought, and the dispersal capacity did not change significantly. Furthermore, urbanisation promoted increases in the average dispersal capacities of spider communities. Additionally, urbanisation favoured spider communities with larger body sizes and longer activity periods. The loss of woody areas at the landscape level was associated with trait shifts to carabid communities with larger body sizes, shorter activity periods, higher drought tolerances and strongly decreased dispersal capacities. Decreases in activity periods and dispersal capacities were also found in spider communities.Our study demonstrates that human‐induced changes in land use alter key functional traits of carabid and spider communities in the long term. The detected trait shifts in arthropod communities likely have important consequences for their functional roles in ecosystems. [ABSTRACT FROM AUTHOR]

Diet composition and its ecological drivers are rarely investigated in coexisting closely related species. We used a molecular approach to characterize the seasonal variation in diet composition in four spiny lizard species inhabiting a mountainous ecosystem. DNA metabarcoding revealed that the lizards Sceloporus aeneus, S. bicanthalis, S. grammicus, and S. spinosus mostly consumed arthropods of the orders Hemiptera, Araneae, Hymenoptera, and Coleoptera. The terrestrial lizards S. aeneus and S. bicanthalis mostly predated ants and spiders, whereas the arboreal–saxicolous S. grammicus and saxicolous S. spinosus largely consumed grasshoppers and leafhoppers. The taxonomic and phylogenetic diversity of the prey was higher during the dry season than the rainy season, likely because reduced prey availability in the dry season forced lizards to diversify their diets to meet their nutritional demands. Dietary and phylogenetic composition varied seasonally depending on the species, but only dietary composition varied with altitude. Seasonal dietary turnover was greater in S. spinosus than in S. bicanthalis, suggesting site‐specific seasonal variability in prey availability; no other differences among species were observed. S. bicanthalis, which lives at the highest altitude in our study site, displayed interseasonal variation in diet breadth. Dietary differences were correlated with the species' feeding strategies and elevational distribution, which likely contributed to the coexistence of these lizard species in the studied geographic area and beyond. [ABSTRACT FROM AUTHOR]

Maternally‐inherited sex ratio distorting microbes (SRDMs) are common among arthropod species. Typically, these microbes cause female‐biased sex ratios in host broods, either by; killing male offspring, feminising male offspring, or inducing parthenogenesis. As a result, infected populations can experience drastic ecological and evolutionary change. The mechanism by which SRDMs operate is likely to alter their impact on host evolutionary ecology; despite this, the current literature is heavily biased towards a single mechanism of sex ratio distortion, male‐killing. Furthermore, amidst the growing concerns surrounding the loss of arthropod diversity, research into the impact of SRDMs on the viability of arthropod populations is generally lacking. In this study, using a theoretical approach, we model the epidemiology of an understudied mechanism of microbially‐induced sex ratio distortion—feminisation—to ask an understudied question—how do SRDMs impact extinction risk in a changing environment? We constructed an individual‐based model and measured host population extinction risk under various environmental and epidemiological scenarios. We also used our model to identify the precise mechanism modulating extinction. We find that the presence of feminisers increases host population extinction risk, an effect that is exacerbated in highly variable environments. We also identified transmission rate as the dominant epidemiological trait responsible for driving extinction. Finally, our model shows that sex ratio skew is the mechanism driving extinction. We highlight feminisers and, more broadly, SRDMs as important determinants of the resilience of arthropod populations to environmental change. [ABSTRACT FROM AUTHOR]

BACKGROUND: Structural and chemical plant defence traits may reduce the efficacy of biological control agents in integrated pest management. Breeding programmes have shown arthropod predators' potential to acclimate to challenging host plants. However, whether and how these predators adapt to novel plant environments remain unclear. Using the predatory mite Phytoseiulus persimilis – herbivorous mite Tetranychus urticae system in an experimental evolution setup, we studied the adaptation mechanisms to tomato and cucumber, plants that possess a distinct repertoire of defensive traits. RESULTS: Experimental evolution experiments on whole plants revealed that allowing P. persimilis to adapt to tomatoes led to an ~100% larger population size. Independent feeding assays showed that tomato‐ and cucumber‐adapted prey reduced predator fecundity. The deleterious effect of ingesting low‐quality prey persisted after adaptation of the predator to both cucumber and tomato. We demonstrated that jasmonic acid (JA)‐dependent defences reduce prey quality by evaluating predator performance on prey fed on JA defence‐deficient tomato plants. Transcriptomic profiling of the replicated P. persimilis lines showed that long‐term propagation on tomato and cucumber plants produces distinctive gene‐expression levels. Predator adaptation to tomatoes results in the loss of a large transcriptional response, in which predicted cuticle‐building rather than detoxification pathways are affected. CONCLUSION: We showed that the adaptation of predatory arthropods to a novel, challenging plant does not necessarily occur via the prey, but rather through the physical environment of the plant. We provided first insights into the underlying molecular mechanisms. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Unplanned urban development has consequences for natural ecosystems, resulting in habitat fragmentation and loss. Arthropod responses to urbanisation are well documented in the Global North, but no clear responses are found for the Global South.We assessed beta diversity, composition, richness and abundance responses of arthropods in Turnera subulata in an urbanisation gradient.Urbanisation affected arthropod communities' composition, and more urbanised areas showed lower insect richness and abundance. Arthropod taxa did not respond homogeneously to urbanisation.Turnover best explained the change in beta diversity along the urbanisation gradient, indicating urbanisation causes species replacement compared to less urbanised areas.We found negative results of urbanisation on the arthropod community on flowers of T. subulata. Our results are a first approximation to the effects of rural–urban gradient of urbanisation on multiple arthropod taxon in Brazil, highlighting the need for maintenance of urban green areas to allow the existence of a richer and more diverse community, especially in the face of the arthropod biodiversity crisis that we are experiencing. [ABSTRACT FROM AUTHOR]

Degraded areas are often restored through active revegetation; however, recolonization by animals is rarely engineered. Recolonization may be rapid for species with strong dispersal abilities. However, poor dispersers, such as many flightless arthropods, may struggle to recolonize newly restored sites. Actively reintroducing or "rewilding" arthropods may therefore be necessary to facilitate recolonization and restoration of arthropod communities and the ecological functions they perform. However, active interventions are rare. The purpose of this study was twofold. First, we asked whether potential source remnant arthropod communities were dispersal‐constrained and struggling to recolonize restoration sites. Second, we tested whether reintroducing entire arthropod communities from remnant populations would help dispersal‐constrained species establish during farmland ecological restoration in southern Australia. Rewilding was conducted in summer 2018 by transplanting leaf litter, soil, and entire communities contained within it from remnant source populations into geographically isolated restoration sites, which were paired with untreated controls (n = 6 remnant, rewilding transplant, and control sites). We collected leaf litter and extracted arthropod communities 19 months after the initial rewilding event, then sequenced mite, springtail, and insect communities using a metabarcoding approach. Within all groups, community similarity decreased with spatial distance between sites, suggesting significant dispersal barriers. However, only mite communities showed a strong response to rewilding, which was expressed as increased compositional similarity toward remnant sites and greater species richness relative to controls. Our results demonstrate that many arthropod species may struggle to recolonize geographically isolated restoration sites and that full community restoration requires active interventions via rewilding. [ABSTRACT FROM AUTHOR]

Cultural practices modify agroecosystems to prevent or reduce pest outbreaks, but they may be detrimental to beneficial arthropods and non‐target effects are not commonly evaluated. Plastic mulches are an effective management practice for spotted‐wing drosophila (Drosophila suzukii Matsumura) since they increase UV radiance in the plant canopy to reduce larval infestation of fruit. In this 2‐year study, we evaluated how black, white, and metallic plastic mulches impact populations of arthropods, including predators of D. suzukii and raspberry pollinators in Wisconsin. The three plastic mulches did not affect arthropod richness and did not affect the abundance of about 65% of arthropod groups identified. In the raspberry canopy, the black mulch decreased the abundance of Orthoptera and Thysanoptera and increased Orius spp.; the white mulch increased Diptera, Thysanoptera, and Orius spp.; and the metallic mulch decreased Coleoptera, micro‐Hymenoptera, Orthoptera, and Thysanoptera. On the ground, all mulches decreased the abundance of Gryllidae, the black and metallic increased Formicidae, and the white increased Staphylinidae. We reported 10 insect groups visiting raspberry flowers. Bombus impatiens Cresson was the most common, accounting for 82% of flower visits. The plastic mulches did not reduce flower visitation, though the white plastic mulch increased the abundance of B. impatiens compared to the other mulch treatments. Plastic mulches can reduce populations of pests such as D. suzukii and overall have no severe non‐target effects on other arthropods in Wisconsin raspberry. [ABSTRACT FROM AUTHOR]

Like other urban green spaces, urban community gardens can act as biodiversity refugees, especially for small organisms like arthropods. In turn, arthropods can provide important ecosystem pest control services to these agroecosystems. Thus, an often‐asked question among urban gardeners is how to improve gardens and surrounding areas for natural enemies and associated pest control services. We examine how local vegetation and garden characteristics, as well as the surrounding landscape composition, affect ground‐dwelling beetles (Coleoptera: Carabidae and Staphylinidae), spiders (Araneae), opilionids (Opiliones), and ladybird beetles (Coleoptera: Coccinellidae), all of which are important predators. In the summer of 2019, we collected predators, vegetation, ground cover, and garden and landscape characteristic data from 10 community gardens in the city of Seattle, Washington. We found that different groups of natural enemies are associated with different environmental variables and at different scales; probably related to differences in their dispersal capabilities, habits, and diets. Floral variables (number of flowers and number of species in flower) had a negative effect on nonflying natural enemies (spiders, opilionids, and ground‐dwelling beetles), but not on flying ones (ladybird beetles). The only taxon that was significantly affected by a landscape‐scale variable was Opiliones, the only group examined that exclusively disperses by ground. Our results show contrasting results to similar studies in different regions and highlight the need to expand the taxa and regions of study. [ABSTRACT FROM AUTHOR]

Agricultural intensification is leading to conversion of cocoa agroforestry towards monocultures across the tropics. In the context of cocoa agriculture, arthropods provide a range of ecosystem services and dis‐services. Arthropod pests (e.g., mirids and mealybugs) can cause major damage to crops, whilst pollinators and natural enemies (e.g., predatory insects and parasitoids) have the potential to enhance agricultural yields. Understanding how intensification of cocoa farming affects different arthropod groups is therefore important in maximising the abundance of beneficial arthropod taxa and reducing pest burdens. However, little is known about the influences of agricultural intensification on tropical arthropod communities, especially in Africa, where ~70% of the world's cocoa is produced.Most research on arthropod communities considers data from different sampling methods separately, as proxies of abundance; whilst these proxies can be informative, estimating true abundance enables direct comparison between arthropod taxa, and therefore the study of community dynamics. Here, we develop a Bayesian hierarchical model that integrates data from three common arthropod survey techniques to estimate population size of arthropod orders and to investigate how arthropod community composition responds to farm shade cover (an indicator of management intensity).Our results show that eight of 11 arthropod taxa responded to farm shade cover; importantly, brown capsids (the primary pest of cocoa in Africa), Coleoptera pests and Hemiptera pests decreased with increasing farm shade cover, whilst Araneae (natural enemies) and Diptera (potential pollinators) were more abundant in shady farms.Synthesis and applications. To achieve lower pest burdens and higher abundances of potential pollinators and natural enemies, African cocoa farms should maintain a dense canopy of shade trees. The current shift towards high‐intensity cocoa farming in Africa could result in long‐term losses due to pest infestations and loss of arthropod‐mediated ecosystem services. [ABSTRACT FROM AUTHOR]

Our limited knowledge about the ecological drivers of global arthropod decline highlights the urgent need for more effective biodiversity monitoring approaches. Monitoring of arthropods is commonly performed using passive trapping devices, which reliably recover diverse communities, but provide little ecological information on the sampled taxa. Especially the manifold interactions of arthropods with plants are barely understood. A promising strategy to overcome this shortfall is environmental DNA (eDNA) metabarcoding from plant material on which arthropods leave DNA traces through direct or indirect interactions. However, the accuracy of this approach has not been sufficiently tested. In four experiments, we exhaustively test the comparative performance of plant‐derived eDNA from surface washes of plants and homogenized plant material against traditional monitoring approaches. We show that the recovered communities of plant‐derived eDNA and traditional approaches only partly overlap, with eDNA recovering various additional taxa. This suggests eDNA as a useful complementary tool to traditional monitoring. Despite the differences in recovered taxa, estimates of community α‐ and β‐diversity between both approaches are well correlated, highlighting the utility of eDNA as a broad scale tool for community monitoring. Last, eDNA outperforms traditional approaches in the recovery of plant‐specific arthropod communities. Unlike traditional monitoring, eDNA revealed fine‐scale community differentiation between individual plants and even within plant compartments. Especially specialized herbivores are better recovered with eDNA. Our results highlight the value of plant‐derived eDNA analysis for large‐scale biodiversity assessments that include information about community‐level interactions. [ABSTRACT FROM AUTHOR]

Theory generally predicts that host specialisation and dispersal should evolve jointly. Indeed, many models predict that specialists should be poor dispersers to avoid landing on unsuitable hosts while generalists will have high dispersal abilities. Phytophagous arthropods are an excellent group to test this prediction, given extensive variation in their host range and dispersal abilities. Here, we explore the degree to which the empirical literature on this group is in accordance with theoretical predictions. We first briefly outline the theoretical reasons to expect such a correlation. We then report empirical studies that measured both dispersal and the degree of specialisation in phytophagous arthropods. We find a correlation between dispersal and levels of specialisation in some studies, but with wide variation in this result. We then review theoretical attributes of species and environment that may blur this correlation, namely environmental grain, temporal heterogeneity, habitat selection, genetic architecture, and coevolution between plants and herbivores. We argue that theoretical models fail to account for important aspects, such as phenotypic plasticity and the impact of selective forces stemming from other biotic interactions, on both dispersal and specialisation. Next, we review empirical caveats in the study of this interplay. We find that studies use different measures of both dispersal and specialisation, hampering comparisons. Moreover, several studies do not provide independent measures of these two traits. Finally, variation in these traits may occur at scales that are not being considered. We conclude that this correlation is likely not to be expected from large‐scale comparative analyses as it is highly context dependent and should not be considered in isolation from the factors that modulate it, such as environmental scale and heterogeneity, intrinsic traits or biotic interactions. A stronger crosstalk between theoretical and empirical studies is needed to understand better the prevalence and basis of the correlation between dispersal and specialisation. [ABSTRACT FROM AUTHOR]

BACKGROUND: Maximizing the effectiveness of natural pest control requires a detailed understanding of how service delivery is affected by natural enemy community diversity and composition. Many studies have investigated the effects of natural enemy abundance and species richness on pest control. Studies examining the effects of evenness and species identity are fewer and have produced inconsistent results. Here we test the effects of arthropod predator community evenness and species identity on natural pest control by exposing aphid (Sitobion avenae) colonies in experimental cages to arthropod predator communities that had the same abundance and species richness but differed in evenness and dominant species. RESULTS: We found that the identity of the most dominant species in the arthropod predator community predominantly drove the pest control efficiency. However, additional to the effects of species identity, we also found a causal positive relationship between the evenness of arthropod predator communities and the suppression of pest growth. CONCLUSION: Our results provide support for the hypothesis that ecosystem service provision is generally a function of the abundance and efficiency of the most dominant species of the service‐providing groups. This could partly explain why management practices aiming at promoting abundance of natural enemies often have mixed effects on pest control. Our results also demonstrate that diversity components such as evenness have important additional effects. However, in real‐world ecosystems these effects may be obscured because evenness is generally confounded with abundance or species richness in natural enemy predator communities. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Developing systematic conservation plans depends on a wealth of information on a region's biodiversity. For 'dark taxa' such as arthropods, such data are usually very incomplete and in most cases left out from assessments.Sky islands are important and often fragile biodiversity hotspots. Southern Appalachian high‐elevation spruce–fir forests represent a particularly threatened sky‐island ecosystem, hosting numerous endemic and threatened species, but their arthropods remain understudied.Here we use voucher‐based megabarcoding to explore genetic differentiation among leaf‐litter arthropod communities of these highlands, and to examine the extent to which they represent dispersed communities of more or less coherent species, manageable as a distributed unit. We assembled a dataset comprising more than 6000 COI sequences representing diverse arthropod groups to assess species richness and sharing across peaks and ranges. Comparisons were standardised across taxa using automated species delimitation, measuring endemism levels by putative species.Species richness was high, with sites hosting from 86 to 199 litter arthropod species (not including mites or myriapods). Community profiles suggest that around one fourth of these species are unique to single sky islands and more than one third of all species are limited to a particular range. Across major taxa, endemicity was lowest in Araneae, and highest in neglected groups like Isopoda, Pseudoscorpionida, Protura and Diplura.Southern Appalachian sky islands of spruce–fir habitat host significantly distinct leaf‐litter arthropod communities, with high levels of local endemicity. This is the first work to provide such a clear picture of peak and range uniqueness for a taxonomically broad sample. Ensuring the protection of a sizeable fraction of high‐elevation litter species richness will therefore require attention at a relatively fine spatial scale. [ABSTRACT FROM AUTHOR]

Novel wildfire regimes are rapidly changing global ecosystems and pose significant challenges for biodiversity conservation and ecosystem management. In this study, we used DNA metabarcoding to assess the response of arthropod pollinator communities to large‐scale wildfires across diverse habitat types in California. We sampled six reserves within the University of California Natural Reserve System, each of which was partially burned in the 2020 Lightning Complex wildfires in California. Using yellow pan traps to target pollinators, we collected arthropods from burned and unburned sites across multiple habitat types including oak woodland, redwood, scrub, chamise, grassland, forest, and serpentine habitats. We found no significant difference in alpha diversity values between burned and unburned sites; instead, seasonal variations played a significant role in arthropod community dynamics, with the emergence of plant species in Spring promoting increased pollinator richness at all sites. When comparing all sites, we found that burn status was not a significant grouping factor. Instead, compositional differences were largely explained by geographic differences, with distinct communities within each reserve. Within a geographic area, the response of arthropods to fire was dependent on habitat type. While communities in grasslands and oak woodlands exhibited recovery following burn, scrublands experienced substantial changes in community composition. Our study highlights the importance of examining community responses to wildfires across broad spatial scales and diverse habitat types. By understanding the nuanced dynamics of arthropod communities in response to fire disturbances, we can develop effective conservation strategies that promote resilience and maintain biodiversity in the face of increasing wildfire frequency and severity driven by climate change. [ABSTRACT FROM AUTHOR]

Microhabitats and environmental conditions in eucalypts vary depending on the growth phase. Response of surface-active arthropods to eucalypt growth phases is unclear; yet, it can be an important contribution in forest management. Thus, we investigated the response of surface-active arthropods to three eucalypt age groups. We collected arthropods in a 7-month-old, 18-month-old, and 53-month-old eucalypts since planting. Eucalyptus age did not affect species richness. However, assemblages differed between the 53-month-old and 7-month-old eucalypts. Therefore, different eucalypt ages can enhance arthropod conservation, since they differ in terms of microhabitats and environmental conditions. [ABSTRACT FROM AUTHOR]

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Current understanding of ecological and evolutionary processes underlying island biodiversity is heavily shaped by empirical data from plants and birds, although arthropods comprise the overwhelming majority of known animal species, and as such can provide key insights into processes governing biodiversity. Novel high throughput sequencing (HTS) approaches are now emerging as powerful tools to overcome limitations in the availability of arthropod biodiversity data, and hence provide insights into these processes. Here, we explored how these tools might be most effectively exploited for comprehensive and comparable inventory and monitoring of insular arthropod biodiversity. We first reviewed the strengths, limitations and potential synergies among existing approaches of high throughput barcode sequencing. We considered how this could be complemented with deep learning approaches applied to image analysis to study arthropod biodiversity. We then explored how these approaches could be implemented within the framework of an island Genomic Observatories Network (iGON) for the advancement of fundamental and applied understanding of island biodiversity. To this end, we identified seven island biology themes at the interface of ecology, evolution and conservation biology, within which collective and harmonized efforts in HTS arthropod inventory could yield significant advances in island biodiversity research. [ABSTRACT FROM AUTHOR]

Scorpions are ancient and historically renowned for their potent venom. Traditionally, the systematics of this group of arthropods was supported by morphological characters, until recent phylogenomic analyses (using RNAseq data) revealed most of the higher‐level taxa to be non‐monophyletic. While these phylogenomic hypotheses are stable for almost all lineages, some nodes have been hard to resolve due to minimal taxonomic sampling (e.g. family Chactidae). In the same line, it has been shown that some nodes in the Arachnid Tree of Life show disagreement between hypotheses generated using transcritptomes and other genomic sources such as the ultraconserved elements (UCEs). Here, we compared the phylogenetic signal of transcriptomes vs. UCEs by retrieving UCEs from new and previously published scorpion transcriptomes and genomes, and reconstructed phylogenies using both datasets independently. We reexamined the monophyly and phylogenetic placement of Chactidae, sampling an additional chactid species using both datasets. Our results showed that both sets of genome‐scale datasets recovered highly similar topologies, with Chactidae rendered paraphyletic owing to the placement of Nullibrotheas allenii. As a first step toward redressing the systematics of Chactidae, we establish the family Anuroctonidae (new family) to accommodate the genus Anuroctonus. [ABSTRACT FROM AUTHOR]

The worldwide decline of insects is one of the major challenges for humankind. One of its main drivers is intensive farming, which reduces habitats and food resources for insect populations and causes direct mortality by pesticides. In addition, mowing of grassland poses another threat to insects, especially when it is done frequently, such as in roadside verges. Roadside verges comprise large areas worldwide and can serve as habitats for animals and plants and as corridors to connect populations when they are maintained ecologically, for example when mowing is done arthropod‐friendly and with low frequency. Microhymenoptera are highly diverse, mostly show a parasitoid lifestyle and occur in large numbers in meadows and grasslands. Although they have an important ecological function in regulating their arthropod host populations, they were mostly neglected in studies on the influence of mowing on insects. Therefore, we assessed which families of microhymenoptera occur in roadside verges and meadows, examined if they are affected by the mowing process with a conventional mulching mower, and studied which groups benefit from arthropod‐friendly mowing, using the mowing head Eco 1200 plus from MULAG, and a flushing bar made of track tarpaulin. In our experimental grassland plots, we found specimens of 18 families from the six microhymenoptera superfamilies Chalcidoidea, Ceraphronoidea, Diaprioidea, Ichneumonoidea, Platygastroidea and Proctotrupoidea. Mowing with a conventional mulching mower caused a significant loss of up to 64% for parasitoid Hymenoptera. The Eco 1200 plus showed an arthropod‐friendly effect only on the number of individuals of Chalcidoidea, saving 38% of individuals compared with the conventional mower. The flushing bar showed a significant effect on total number of individuals with a reduction only on Chalcidoidea and a tendency for Ichneumonoidea with 30% and 47%, respectively. Our study demonstrates the detrimental effect of mowing with a conventional mulching mower on microhymenoptera and shows that this effect can be partly reversed for Chalcidoidea and Ichneumonoidea through the arthropod‐friendly mower and a flushing bar. Our study highlights the importance to consider microhymenoptera in the context of insect decline. [ABSTRACT FROM AUTHOR]

BACKGROUND: Integrated pest management (IPM) has a long history in fruit production and has become even more important with the implementation of the EU directive 2009/128/EC making IPM mandatory. In this study, we surveyed 30 apple orchards in Norway for 3 years (2016–2018) monitoring pest‐ and beneficial arthropods as well as evaluating fruit damage. We obtained growers' diaries of pest management and used these data to study positive and negative correlations of pesticides with the different arthropod groups and damage due to pests. RESULTS: IPM level had no significant effects on damage of harvested apples by arthropod pests. Furthermore, damage by arthropods was mainly caused by lepidopteran larvae, tortricids being especially important. The number of insecticide applications varied between 0 and 3 per year (mean 0.8), while acaricide applications varied between 0 and 1 per year (mean 0.06). Applications were often based on forecasts of important pest species such as the apple fruit moth (Argyresthia conjugella). Narrow‐spectrum insecticides were commonly used against aphids and lepidopteran larvae, although broad‐spectrum neonicotinoid (thiacloprid) insecticides were also applied. Anthocorid bugs and phytoseiid mites were the most abundant natural enemies in the studied orchards. However, we found large differences in abundance of various "beneficials" (e.g., lacewings, anthocorids, parasitic wasps) between eastern and western Norway. A low level of IPM negatively affected the abundance of spiders. CONCLUSION: Lepidoptera was found to be the most important pest group in apple orchards. Insecticide use was overall low, but number of spray applications and use of broad‐spectrum insecticides varied between growers and regions. IPM level did not predict the level of fruit damage by insects nor the abundance of important pests or most beneficial groups in an apple orchard. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Suction sampling is increasingly being used to estimate abundance and diversity of epigeal arthropods, yet no study has quantified its efficiency to simultaneously assess diversity at different taxonomic and functional scales. Here, we evaluated the efficiency of this method (G‐Vac) relative to the pitfall (Barber) trap, which has been used for a long time, and their possible complementarity. To do that, we compared several diversity metrics of a wide range of arthropod taxa, with a particular focus on spiders (species level), and using functional traits such as trophic diet, hunting guild, and body size. Sampling took place in some coastal grasslands of Brittany (France) using a spatially paired design of vacuuming and unfenced pitfall trapping. In total, 21159 arthropods were identified to order or family levels, including 1018 adult spiders identified to species. Suction sampling was more efficient than pitfall trapping in collecting phytophagous arthropods, web‐builders, and small species living in the vegetation compared to detritivores, large‐bodied arthropods, and spiders living near the soil surface. We conclude that short‐term G‐Vac suction is more interesting than pitfall trapping to obtain a 'snapshot' of patterns in taxonomic richness. However, for assessing functional diversity, G‐Vac suction and pitfall trapping are complementary sampling methods. [ABSTRACT FROM AUTHOR]

Metacommunity theory has advanced scientific understanding of how species interactions and spatial processes influence patterns of biodiversity and community structure across landscapes. While the central tenets of metacommunity theory have been promoted as pivotal considerations for conservation management, few field experiments have tested the validity of metacommunity predictions. Here, we tested one key prediction of metacommunity theory—that decreasing habitat connectivity should erode metacommunity structure by hindering species movement between patches. For 2 years, we manipulated an experimental old‐field grassland ecosystem via mowing to represent four levels of habitat connectivity: (1) open control, (2) full connectivity, (3) partial connectivity, and (4) no connectivity. Within each treatment plot (10 × 10 m, n = 4 replicates), we measured the abundance and diversity (i.e., alpha and beta) of both flying and ground arthropods using sticky and pitfall traps, respectively. We found that the abundance and diversity of highly mobile flying arthropods were unaffected by habitat connectivity, whereas less mobile ground arthropods were highly impacted. The mean total abundance of ground arthropods was 2.5× and 2× higher in the control and partially connected plots compared to isolated patches, respectively. We also reveal that habitat connectivity affected the trophic interactions of ground arthropods, with predators (e.g., wolf spiders, ground spiders) being highly positively correlated with micro‐detritivores (springtails, mites) but not macro‐detritivores (millipedes, isopods) as habitat connectivity increased. Together these findings indicate that changes in habitat connectivity can alter the metacommunity structure for less mobile organisms such as ground arthropods. Because of their essential roles in terrestrial ecosystem functioning and services, we recommend that conservationists, restoration practitioners, and land managers include principles of habitat connectivity for ground arthropods when designing biodiversity management programs. [ABSTRACT FROM AUTHOR]