Diversity Of Arthropod Communities Research Articles

A Comparative Analysis of Island vs. Mainland Arthropod Communities in Coastal Grasslands Belonging to Two Distinct Regions: São Miguel Island (Azores) and Mainland Portugal

Coastal grasslands host diverse arthropod communities and provide important ecosystem services. Islands, being isolated environments, are expected to have simpler ecosystems than continental areas, with the few successful colonizing species often attaining high densities; however, these patterns are still poorly documented for coastal grassland arthropods. We conducted a comparative study of the biodiversity of arthropod communities in two distinct coastal grassland ecosystems (Portugal mainland and the Azores) with the following objectives: (a) to investigate the arthropod community composition in both locations; (b) to compare the diversity profiles in both locations; (c) to investigate potential density compensation in the island’s arthropod communities. For four months, arthropods were collected on the Island of São Miguel, Setúbal Peninsula, and Sine’s region and subsequently classified into taxonomic groups. With the data collected, Hill Numbers were calculated for each region. We confirmed that the richness on the mainland was higher than in the Azores, and we found some apparent abundance compensation in the Azores. At the same time, we also observed that many species in the Azores are also present in the continental coastal grasslands of mainland Portugal.

Differences in urban arthropod communities may not limit the nestling diet of a generalist songbird

Anthropogenic land use, including urbanization, has caused population declines across diverse taxa including arthropods and songbirds. Declines in one taxa can impact other groups based on its role in a community. In particular, declines in lower trophic level taxa, such as arthropods, could have negative impacts on higher trophic level species. Here, we examined how urban arthropod communities compare to rural ones and how these differences may impact song sparrow (Melospiza melodia) nestlings living in urban and rural habitats. We quantified differences in the abundance, biomass, and diversity of arthropod communities between replicate urban and rural sites. At the same sites, we also compared the stomach contents of nestlings because song sparrows rely upon arthropod prey during development. We found that the arthropod community in urban habitats had lower average abundance, average biomass, and Simpson's diversity compared to rural habitats. The arthropod communities also significantly differed in the relative abundance of some higher trophic level taxa, such as spiders. However, we found no difference in the total stomach content mass, nor the mass of invertebrate food items in the stomachs of urban and rural nestlings. Thus, though urban habitats had lower availability of arthropods, possibly driven by the simplification urban habitats, there was no evidence of a negative impact on the quantity of food provided to urban song sparrow nestlings.

Simulation of red mud/phosphogypsum-based artificial soil engineering applications in vegetation restoration and ecological reconstruction

Red mud and phosphogypsum are two of the most typical bulk industrial solid wastes. How they can be efficiently recycled as resources on a large scale and at low costs has always been a global issue that urgently needs to be solved. By constructing a small-scale test site and preparing two types of artificial soils using red mud and phosphogypsum, this study simulated their engineering applications in vegetation restoration and ecological reconstruction. According to the results of this study, the artificial soils contained a series of major elements (e.g. O, Si, Al, Fe, Ca, Na, K, and Mg) similar to those in common natural soil, and preliminarily possessed basic physicochemical properties (pH, moisture, organic matter, and cation exchange capacity), main nutrient conditions (nitrogen, phosphorus and potassium), and biochemical characteristics that could meet the demands of plant growth. A total of 18 different types of adaptable plants (e.g. wood, herbs, flowers, succulents, etc) grew in the test sites, indicating that the artificial soils could be used for vegetation greening and landscaping. The preliminary formation of microbial (fungal and bacterial) community diversity and the gradually enriched arthropod community diversity reflected the constantly improving quality of the artificial soils, suggesting that they could be used for the gradual construction of artificial soil micro-ecosystems. Overall, the artificial soils provided a feasible solution for the large-scale, low-cost, and highly efficient synergistic disposal of red mud and phosphogypsum, with enormous potential for future engineering applications. They are expected to be used for vegetation greening, landscaping, and ecological environment improvement in tailings, collapse, and soil-deficient areas, as well as along municipal roads.

Mistletoes benefit from initiating cascading effects in a cactus–stem borers–arthropods system: A positive feedback

Abstract Parasitic plants may indirectly modify arthropod community structure by inducing resistance/susceptibility in host plants. In the Atacama Desert, the mistletoe Tristerix aphyllus initiates cascading effects on its cactus host, Echinopsis chiloensis, inducing susceptibility to stem‐borer beetles, whose brood chambers are colonized by a diverse arthropod community. We evaluated whether those cascading effects initiated by Tristerix generate a positive or negative feedback loop on this parasitic plant. A positive or negative feedback loop would occur if the mistletoe‐elicited indirect effects on arthropod community result in increased or decreased mistletoe fitness, respectively. Specifically, by way of field sampling, experimental manipulation of number of brood chambers, and structural equation modelling, we assessed the indirect impact of number of brood chambers on Tristerix fitness mediated by its influence on the abundance of arthropod trophic guilds (omnivores, nectarivores, herbivores and predators). We found that the number of brood chambers had a positive indirect effect on mistletoe fitness, likely mediated by the increased abundance of nectarivores. The number of brood chambers was positively associated with the abundance of predators, nectarivores and herbivores. However, nectarivores were the only trophic guild showing a positive association with both number of brood chambers and Tristerix fitness. This positive feedback loop, together with the known pattern of specific disperser‐mediated cyclic reinfection of cacti by Tristerix, would indicate that mistletoe infection may ultimately threaten cactus survival.

The diversity and ecological roles of insects and arachnids in arabica coffee (Coffea arabica) plantation in Palasari, Bandung Regency

Keanekaragaman komunitas artropoda dapat dijadikan sebagai bioindikator perubahan lingkungan khususnya pada sistem budi daya kopi dengan sistem pengelolaan yang beragam. Sistem pengelolaan lahan yang beragam akan menimbulkan perubahan struktur komunitas dan fungsi ekologis artropoda. Tujuan dari penelitian ini untuk menganalisis keanekaragaman dan peranan serangga dan Arachnida pada perkebunan kopi Arabika di Kabupaten Bandung. Sampel diambil dari perkebunan kopi di Desa Legok Nyenang, Kabupaten Bandung dengan menetapkan lima plot sampel berukuran 100 m2 per plot dengan jarak antar plot sejauh 50 m. Serangga dan Arachnida terestrial diambil menggunakan jaring ayun, perangkap nampan kuning, dan beating sheet. Sampel yang diperoleh diidentifikasi berdasarkan karakter morfologi hingga tingkat morfospesies. Sebanyak 269 jenis serangga (11 ordo dan 98 famili, total 669 individu) dan 23 jenis Aachnida (satu ordo dan 13 famili, total 44 individu) berhasil dikumpulkan dari perkebunan kopi Arabika Palasari. Peran ekologi yang paling beragam adalah fitofag. Spesies fitofag yang dominan adalah Nysius sp. (Hemiptera: Lygaeidae). Musuh alami yang dominan, yaitu parasitoid Megacampsomeris prismatica (Hymenoptera: Scoliidae) dan predator, Tetragnatha sp. (Araneae: Tetragnathidae), sedangkan fungsi ekologis yang jumlahnya paling rendah adalah serangga penyerbuk (Hymenoptera: Apidae). Keanekaragaman jenis serangga dan Arachnida yang ditemukan pada pertanaman kopi di Kabupaten Bandung termasuk dalam kategori tinggi (H’ = 5,10), meskipun indeks kemerataan dan dominansinya tergolong rendah. Hasil penelitian ini menunjukkan bahwa pertanaman kopi merupakan ekosistem yang potensial bagi konservasi keanekaragaman hayati serangga dan Arachnida predator sehingga praktik budi daya dan pengelolaan hama harus diarahkan untuk melindungi serangga menguntungkan, seperti musuh alami dan polinator.

Insecticides may compromise the benefits of tree-crop diversification on arthropod biodiversity in cocoa agroforestry smallholdings

ABSTRACT Arthropods play vital roles in ecosystem functions, yet their distribution is subjected to environmental factors. Hence, this study investigates the impact of habitat features on arthropod communities within cocoa smallholdings under different farming practices: agroforestry and monoculture systems. We conducted arthropod sampling using yellow sticky traps and assessed the habitat features at each plantation twice to capture temporal variations in arthropod populations. The study recorded 2945 individual arthropods belonging to eight different functional groups. The most abundant functional group was saprophagous, followed by phytophagous, parasitoid, predator, mycetophagous, frugivorous, palynivore, and nectarivorous group. Using Generalized Linear Mixed Models (GLMMs), we found that the abundance of phytophagous and predatory arthropods increases with leaf litter, while it decreases with saprophagous arthropods. Our findings suggest that tree-crop diversification within cocoa smallholdings can play a significant role in preserving higher arthropod biodiversity, particularly when these smallholdings remain free from chemical insecticide use. Canopy cover was also found to positively affect the variability of arthropods indicating that it is a crucial factor affecting arthropod biodiversity. This study underscores the significance of integrating agroforestry systems into cocoa production landscapes, particularly those utilizing agrochemicals, to support diverse arthropod communities and promote sustainable cocoa production.

Beneficial effects of native broadleaved forests on canopy beetle diversity are not reduced by admixture of non‐native conifers

Abstract Biodiversity loss and vast forest diebacks due to climate change‐induced disturbances require adapted forest management strategies that reconcile economic interests and conservation. Tree species selection, including admixture of fast‐growing and drought‐tolerant non‐native species to native forests, is an increasingly considered approach. However, we lack data on how such mixtures affect native forest biodiversity, especially for the sparsely researched major above‐ground part of trees, the canopy. In 40 temperate forest plots in northwest Germany, we investigated how monocultures and admixtures of introduced fast‐growing conifers (native Norway spruce planted outside its natural range and non‐native Douglas fir) to native broadleaved European beech forests affect abundance, biomass, taxonomic and functional diversity and community composition of canopy beetles across trophic guilds. Diverse arthropod communities are vital contributors to forest health and resilience, and therefore valuable indicators to assess and evaluate forestry measures. Monospecific stands of non‐native Douglas fir reduced canopy beetle abundance and diversity compared to native European beech, exceeding the negative effects of Norway spruce. These effects were more pronounced for herbivorous beetles, while they were less strong for predators. Beetle communities in monospecific Norway spruce stands had low functional richness. European beech and mixtures with non‐native Douglas fir had high dissimilarity between local communities (turnover, i.e. beta diversity) and high total beetle diversity at landscape scale (gamma diversity). Mixtures generally mitigated the negative effects of introduced conifers, including shifts in species community composition compared to native European beech. Synthesis and applications: Monospecific stands of fast‐growing non‐native Douglas fir and native Norway spruce planted outside its natural occurrence showed undesirable effects such as low diversity and a shifted community composition of canopy beetles compared to native European beech. However, mixed stands mitigated negative effects and specifically admixed non‐native Douglas fir did not reduce species turnover and landscape‐scale beetle diversity. In line with recent studies on other forest taxa, we conclude that admixtures of introduced conifers to European beech forests, but not monospecific plantations, can potentially serve as a compromise between conservational and economic interests.

Differential effects of soil conservation practices on arthropods and crop yields

AbstractMany agricultural management tactics, such as reduced tillage, aim to promote biodiversity and ecosystem services. Responses to such tactics can be context dependent, however, and differentially impact (i) functional groups of service‐providing organisms and (ii) crop yields. In canola (Brassica napus L., B. rapa L.) crop fields, we assessed how soil tillage and landscape context (amount of semi‐natural habitat within 1 km of each field) affected arthropod biodiversity and crop yield. We assessed effects of full (multiple tillage passes that leave soil surface bare), intermediate (tilled once and some stubble remains), or no (seed planted directly into last year's stubble) tillage on functional groups with unique diets and reproductive strategies: (i) herbivores, (ii) kleptoparasites, (iii) parasitoids, (iv) pollinators, and (v) predators. Effects of tillage and landscape context on arthropod abundance and diversity varied across functional groups. Pollinators responded strongest to tillage, benefitting from intermediate tillage. Predators and herbivores responded strongly to landscape context, as both were more abundant in landscapes with more semi‐natural habitat. Our results suggest that natural history differences among functional groups mediate effects of landscape context on biodiversity. However, variation in arthropod communities had little effect on canola crop yield. The effects of soil management practices on aboveground arthropods are complex, and practices thought to increase some aspects of agricultural sustainability may not be beneficial in other contexts. Identifying practices such as intermediate tillage that may increase soil quality and arthropod diversity is a key to designing agricultural ecosystems that will effectively benefit both biodiversity and human well‐being.

Organic fertility management in cotton Gossypium hirsutum L. fosters arthropod biodiversity and complements pest suppression

AbstractResearch on economic, ecological and relative benefits from organic and conventional farming systems has gained significant importance. Organic farming increases species diversity, enhances biological control services, and thus complements sustainable pest management. However, published literature is scarce on cotton crops grown organically with respect to the abundance and diversity of biological control agents and their effects on herbivore populations, typically from developing nations. To address the question, the non‐transgenic cotton variety CIM‐573 was cultivated under two fertility management systems, that is, organic and conventional in 2019 and 2021, and subsequently, differences in the abundance and diversity of arthropod communities were carried out. We applied cattle manure in organic fields 1 month before planting; however, synthetic fertilizers were used in conventional fields. We sampled arthropods weekly after 7 weeks of sowing from the middle rows of treatments for both types of fields. We recorded 10 herbivores as well as eight natural enemy species. Herbivores were more abundant in conventional cotton. However, natural enemies were higher in organic cotton fields. Principal component analysis of herbivores assemblages depicted that Shannon diversity and abundance were positively correlated in the conventional cotton while Menhinick richness and Simpson dominance index were higher in organic cotton. Likewise, natural enemies' abundance, Shannon diversity, Menhinick richness and Simpson dominance were typically more concentrated in organic cultivated cotton. Regression analysis confirmed that the abundance and diversity of natural enemies played a significant role in lowering herbivores populations. Seed cotton yield was significantly higher in conventional cotton and the yield difference between organic and conventional cotton was 27.98%. Our study clearly demonstrates that organic cotton provides more functional and complementary niches to natural enemies and plays a crucial role in pest suppression. Implications of our results for future pest management with respect to ecosystem services in organically grown cotton crops are also discussed.

Local‐scale abiotic factors influence the organization of rock pool arthropod communities in a biodiversity hotspot

AbstractDetermining drivers of community assembly is central to ecology, and patchily distributed temporary habitats offer an ideal system to study the roles of ecological and evolutionary processes in structuring communities over different spatial scales. We studied functionally diverse arthropod communities in 32 freshwater rock pools on 3 plateaus in the Western Ghats biodiversity hotspot, sampling them throughout their hydroperiod (2–7 months). Using the Hierarchical Modeling of Species Communities approach, we assessed (a) the influence of local (water chemistry, habitat complexity at the pool level) and regional (seasonality in temperature and precipitation at the plateau level) scale abiotic covariates in shaping species' occurrence, (b) the influence of species traits (dispersal/reproductive mode, body size, feeding guild) and phylogenetic relationships on species response to abiotic covariates, and (c) the strength of biotic filtering in the communities. Environmental filtering was the dominant driver of community structure, where the pool‐level covariates (mainly hydroperiod and water chemistry), explained greater variation (56.3%) in species occurrences rather than plateau‐level covariates, that is, climatic seasonality (33.7%). Spatial factors explained only 11% of the variation in species occurrences. The selected traits explained 22% variation in species' responses, with body size responding to the abiotic covariates at both spatial scales. Closely related taxa exhibited shared responses to the abiotic covariates. Only a few residual associations were observed, all among passive dispersers, indicating a low contribution of biotic filtering to community structure. Our results highlight the importance of habitat‐level factors and the key role of evolutionary processes in shaping diversity in this vulnerable landscape characterized by its seasonality.

Effect of Bed Preparation on Native Wildflower Establishment, Weed Control, and Arthropod Presence

Native flowering forbs plantings have been found to support diverse arthropod communities by providing year-round forage and refuge from prey and chemical pollutants. Typically, pollinator habitats are planted from seeds; however, poor establishment and weed pressure often result in limited success of the planting. In this study, we evaluated two bed preparation techniques, a glyphosate treatment with no tillage and tillage with soil fumigant (dazomet) to determine their impact on herbaceous perennial transplants establishment, weed control, and arthropod presence. Our results suggest that forbs grown in beds that are tilled and treated with dazomet exhibit greater growth, produce more blooms, and experience reduced weed pressure compared to plants grown in untilled beds treated with glyphosate. We also found that the bed preparation method had no effect on arthropod activity, despite higher bloom counts in plants grown in beds prepared with tillage and dazomet applications. This research indicates that of the fifteen native flowering forbs examined in this study, a majority attracted abundant and diverse insect populations, despite variations in plant growth and bloom counts due to bed preparation treatments.

Cavity-breeding birds create specific microhabitats for diverse arthropod communities in boreal forests

The nests of secondary cavity-nesters located in tree cavities may form specific microhabitats of conservation importance due to their limited accessibility and availability. Species-specific nesting materials in nests of different secondary cavity-nesters may furthermore provide very different microhabitats for arthropods. The potential differences in arthropod communities inhabiting nests of different bird species in excavated cavities or nest boxes have, however, rarely been studied despite their relevance for conservation. Here we investigated the diversity and composition of arthropod communities in these different cavity types and bird species’ nests in managed boreal forests. We identified morphologically and by DNA-metabarcoding arthropods in nest materials that were collected in and compared between (i) woodpecker-size cavities from seven different combinations of cavity type (nest box or excavated cavity), tree species (aspen or pine) and accumulation history of nest materials (single-season cleaned or uncleaned nest boxes that accumulated nests of passerines or an owl species); and (ii) nests of two different passerine species in small nest boxes. We identified 64 arthropod taxa in ten orders, from which Diptera, Coleoptera, Siphonaptera, and Lepidoptera were the most abundant. Shannon diversity index was similar among the cavity-nest-type combinations, but taxa richness was the highest in the owl nests. The arthropod communities (especially Histeridae beetles) deviated most from the other types of nests in owl and aspen cavity nests with more advanced decomposition of nest material (soil or wet environment related taxa). The differences in arthropod communities between the different nest types point out the importance of the ecological chain “tree cavities—bird nests—arthropod communities”.

Can trap color affect arthropod community attraction in agroecosystems? A test using yellow vane and colorless traps.

Vane trapping is one of the most effective methods for sampling flower-visiting arthropods. Despite its importance in pollinator studies, the effects of trap color on the abundance and richness of pollinators are less understood. To test this, we conducted a 3-season field experiment over 2years with two types of vane traps: yellow and colorless. We set up twelve traps each in three field sites within the Lower Rio Grande Valley in south Texas, planted with Vigna unguiculata, Crotalaria juncea, Raphanus raphanistrum, and Sorghum drummondii. At each site, six colorless vane and six yellow vane traps were placed equidistant from each other. The experiment was replicated three times across three seasons, first during the pre-flowering season, when the crops were in full bloom, and when there was no crop on the field. In total, we collected 1912 insects, out of which 76.7% were pollinators. Generalized Linear Regression analyses showed that yellow traps consistently attracted significantly more arthropods and pollinators, but these differences were also season dependent. Furthermore, we noticed that Hymenoptera, followed by Coleoptera, were the most prevalent orders in both the yellow vane and colorless vane traps. Interestingly, although there was no significant difference in species richness of the arthropods in the yellow and colorless vane traps, our results suggest that trap color plays a significant role in capturing pollinators, including non-target arthropods. Our data add another line of evidence suggesting that trap color should be accounted for designing experiments that estimate pollinator and arthropod community diversity.

Contrasting roles of landscape compositions on shaping functional traits of arthropod community in subtropical vegetable fields

Agricultural intensification and land use transformation are among the main driving forces of the unprecedented decline of biodiversity and ecosystem services in croplands. Trait-based approaches provide a unique framework to detect the potential mechanisms of how this intensification affects biodiversity and alter ecosystem services. However, the potential relationship between arthropod traits and various types of habitats is still poorly understood, especially in subtropical vegetable agroecosystems. Here, we conducted a trait-based approach to evaluate the variable roles of different habitats on functional trait diversity and the structure of the arthropod community in brassica vegetable crops. Twenty-three conventional cruciferous vegetables fields were sampled over two years in three regions in Fujian, China. We found that the increasing proportion of non-brassica vegetable plantations and water bodies negatively affected the functional diversity of arthropods, whereas forest and grassland habitats showed a positive correlation, indicating habitat filtering for certain traits or trait combinations. This study demonstrates the importance of landscape composition as an ecological filter for vegetable arthropod community, and identifies how the proportion of different habitats selected for or against specific functional traits. Our findings support that increasing forest and grassland areas adjacent to vegetable fields can play a vital role in promoting the functional diversity of arthropod communities. Since the natural enemy assemblages supported by these habitats bear combinations of diverse traits adapted to disturbance, they have the potential to enhance pest suppression in the highly variable environment of vegetable crops.

Experimental evidence for a hidden network of higher-order interactions in a diverse arthropod community

Transcending pairwise interactions in ecological networks remains a challenge.1,2,3,4,5 Higher-order interactions (HOIs), the modulation of a pairwise interaction by a third species,6 are thought to play a particularly important role in stabilizing coexistence and maintaining species diversity.7,8,9,10,11,12 However, HOIs have so far only been demonstrated in models9,10,11,12,13,14 or isolated experimental systems including only a few interacting species.7,8,15 Their ubiquity and importance at a community level in the real world remain unknown. We hypothesized that a complex network of HOIs could be constantly modifying pairwise interactions and shaping ecological communities and that consequently the outcome of pairwise interactions would be a product of many influences from distinct sources. Using field experiments, we tested how multiple interactions within a diverse arthropod community associated with the tropical shrub Baccharis dracunculifolia D.C. (Asteraceae) were modified by the removal of ant species or live or hatched insect galls (a non-trophic engineering effect) of the dominant galler species. We revealed an extensive hidden network of HOIs modifying each other and the "visible" pairwise interactions. Most pairwise interactions were affected indirectly by the manipulation of non-interacting taxonomic groups. The pervasiveness of these interaction modifications challenges pairwise approaches to understanding interaction outcomes and could shift our thinking about the structure and persistence of ecological communities. Investigating coexistence mechanisms involving interaction modulation by HOIs may be key to elucidating the underlying causes of the stability and persistence of ecological communities.

More than Moths: Flower Visitors of a Night-Blooming Plant in South Florida Pine Rocklands, USA.

Plants whose flowers open at night but remain open during the day also attract diurnal flower visitors, potentially boosting their pollination rates and providing resources that can support diverse arthropod communities. The rough-leaf velvetseed, Guettarda scabra (Rubiaceae), is an evergreen shrub that thrives only in the imperiled pine rockland habitat in south Florida. Its white, tubular, and fragrant flowers open during late afternoon, exhibiting traits strongly associated with the attraction of nocturnal hawkmoths (Sphingidae). Flowers of G. scabra remain open until the following morning, becoming available to a wider array of visitors, bringing into question the expectation that sphingophilous flowers are visited mainly by hawkmoths. To evaluate whether the flowers of G. scabra are mainly visited by nocturnal hawkmoths and understand the role of this plant in the pine rockland habitat, we characterized the arthropod fauna associated with its flowers during the morning, evening, and at night. We found that most flower visitors were diurnal insects of the orders Hymenoptera and Lepidoptera, although we observed other arthropod groups too. Visitation at night was dominated by two species of hawkmoths. Nectar was the main resource used by the arthropod community during this study. Legitimate visitation and nectar-robbing were the behaviors most frequently observed among the flower visitors. Our results suggest that flowers of the night-blooming G. scabra constitute an important food source for both diurnal and nocturnal arthropod fauna in the fire-dependent pine rocklands of southern Florida. Our study provides novel data to support efforts to conserve and protect pine rocklands and the plants and animals that inhabit them.

Rainforest conversion to rubber and oil palm reduces abundance, biomass and diversity of canopy spiders.

Rainforest canopies, home to one of the most complex and diverse terrestrial arthropod communities, are threatened by conversion of rainforest into agricultural production systems. However, little is known about how predatory arthropod communities respond to such conversion. To address this, we compared canopy spider (Araneae) communities from lowland rainforest with those from three agricultural systems in Jambi Province, Sumatra, Indonesia, i.e., jungle rubber (rubber agroforest) and monoculture plantations of rubber and oil palm. Using canopy fogging, we collected 10,676 spider specimens belonging to 36 families and 445 morphospecies. The four most abundant families (Salticidae N = 2,043, Oonopidae N = 1,878, Theridiidae N = 1,533 and Clubionidae N = 1,188) together comprised 62.2% of total individuals, while the four most speciose families, Salticidae (S = 87), Theridiidae (S = 83), Araneidae (S = 48) and Thomisidae (S = 39), contained 57.8% of all morphospecies identified. In lowland rainforest, average abundance, biomass and species richness of canopy spiders was at least twice as high as in rubber or oil palm plantations, with jungle rubber showing similar abundances as rainforest, and intermediate biomass and richness. Community composition of spiders was similar in rainforest and jungle rubber, but differed from rubber and oil palm, which also differed from each other. Canonical Correspondence Analysis showed that canopy openness, aboveground tree biomass and tree density together explained 18.2% of the variation in spider communities at family level. On a morphospecies level, vascular plant species richness and tree density significantly affected the community composition but explained only 6.8% of the variance. While abundance, biomass and diversity of spiders declined strongly with the conversion of rainforest into monoculture plantations of rubber and oil palm, we also found that a large proportion of the rainforest spider community can thrive in extensive agroforestry systems such as jungle rubber. Despite being very different from rainforest, the canopy spider communities in rubber and oil palm plantations may still play a vital role in the biological control of canopy herbivore species, thus contributing important ecosystem services. The components of tree and palm canopy structure identified as major determinants of canopy spider communities may aid in decision-making processes toward establishing cash-crop plantation management systems which foster herbivore control by spiders.

The bug in a teacup-monitoring arthropod-plant associations with environmental DNA from dried plant material.

Environmental DNA analysis (eDNA) has revolutionized the field of biomonitoring in the past years. Various sources have been shown to contain eDNA of diverse organisms, for example, water, soil, gut content and plant surfaces. Here we show that dried plant material is a highly promising source for arthropod community eDNA. We designed a metabarcoding assay to enrich diverse arthropod communities while preventing amplification of plant DNA. Using this assay, we analysed various commercially produced teas and herbs. These samples recovered ecologically and taxonomically diverse arthropod communities, a total of over a thousand species in more than 20 orders, many of them specific to their host plant and its geographical origin. Atypically for eDNA, arthropod DNA in dried plants shows very high temporal stability, opening up plant archives as a source for historical arthropod eDNA. Considering these results, dried plant material appears excellently suited as a novel tool to monitor arthropods and arthropod–plant interactions, detect agricultural pests and identify the geographical origin of imported plant material. The simplicity of our approach and the ability to detect highly diverse arthropod communities from all over the world in tea bags also highlights its utility for outreach purposes and to raise awareness about biodiversity.

Epigeic arthropod community changes in response to livestock-caused alpine grassland degradation on the eastern Qinghai-Tibetan Plateau

As one of the most important ecosystems, grassland ecosystems maintain an abundance of flora and fauna, and provide humans with rich resources. The structure and function of most grassland ecosystems around the world have been significantly affected by human activity. The overgrazing of livestock and their feces has caused grassland degradation and flora and fauna losses. However, we know little about the relationship between grassland degradation, livestock feces and the arthropod community. In this study, we conducted surveys of the epigeic arthropod community in alpine grassland of the Zoige wetlands in eastern Qinghai-Tibetan Plateau, China. We used ANOVA, multiple linear regression and model-averaging to explore how grassland degradation and livestock feces affected epigeic arthropods community. We found that together grassland degradation and season differently affected taxonomic richness, abundance and different feeding groups of the epigeic arthropod community. Because of the influence of temperature on the epigeic arthropod, the taxonomic richness and abundance of epigeic arthropod community fluctuated dramatically among seasons. Epigeic arthropod community diversity had a significant positive correlation with plant height of all species and Compositae percentage cover in most levels of degradation. The amount of sheep feces had a significant negative correlation with taxonomic richness and abundance of the epigeic arthropod community, because overgrazing sheep reduces the availability of resources and the suitability of micro-habitats for epigeic arthropods. Our study found that moderate levels of disturbance can increase the richness and abundance of epigeic arthropod community over a short period of time. • Epigeic arthropod community diversity in moderately degraded grassland are lower than that in original grassland. • The reduction of plant height is negatively correlated with the diversity of epigeic arthropod community in alpine grassland. • Overgrazing directly and indirectly reduces epigeic arthropods and their applicable micro-habitat. • Grassland degradation affected arthropod community diversity by altering habitats heterogeneity and resources availability.

Impact assessment of genetically modified herbicide-tolerant cotton on arthropod communities

BackgroundCotton (Gossypium spp.) is one of the most important economic crops worldwide, and its production plays an important role in the economy of many countries. Genetically modified herbicide-tolerant (GMHT) crops, which were developed to minimize the losses caused by weeds, have gradually become the most widely adopted genetically modified crops in the world due to their economic and environmental benefits. However, the potential ecological and environmental risks of GMHT crops have attracted extensive attention and controversy. Arthropod communities form a prominent part of the biodiversity of agroecosystems and are important indicators of environmental health. Elucidating the effects of GMHT crops on the diversity of arthropod communities is necessary to ensure the safety of GMHT crops.ResultIn this 2-year study, we investigated the potential impact of GMHT crops on arthropod communities. The GMHT cotton variety GGK2 with glyphosate tolerance and its near-isogenic non-GMHT variety K312 were used for the experimental groups. The Shannon diversity index (H), Simpson diversity index (D), Pielou evenness index (J), and principal co-ordinates analysis (PCoA) of the Bray–Curtis distance were used to evaluate the population dynamics and biodiversity of arthropods in cotton fields. No significant differences were found between GGK2 and K312 in their total abundance of arthropod communities, and biodiversity indexes on most sampling dates. The arthropod composition in the GGK2 and K312 plots was similar. Sampling dates had a significant effect on biodiversity indexes, whereas no clear tendencies related to cotton variety or cotton variety × sampling dates interaction were recorded. In addition, PCoA revealed high similarity between the arthropod communities in the plots of the GMHT cotton variety GGK2 and its near-isogenic variety K312.ConclusionThere was no obvious difference in abundance, diversity indexes of arthropod communities between GMHT cotton variety GGK2 and its near-isogenic variety K312 under the small-scale planting regime.