Arthropod Conservation Research Articles

Effects of livestock on arthropod biodiversity in Iberian holm oak savannas revealed by metabarcoding

Increasing food production while avoiding negative impacts on biodiversity constitutes one of the main challenges of our time. Traditional silvopastoral systems like Iberian oak savannas (“dehesas”) set an example, where free-range livestock has been reared for centuries while preserving a high natural value. Nevertheless, factors decreasing productivity need to be addressed, one being acorn losses provoked by pest insects. An increased and focalized grazing by livestock on infested acorns would kill the larvae inside and decrease pest numbers, but increased livestock densities could have undesired side effects on ground arthropod communities as a whole. We designed an experimental setup including areas under trees with livestock exclosures of different ages (short-term: 1-year exclusion, long-term: 10-year exclusion), along with controls (continuous grazing), using DNA metabarcoding (mitochondrial markers COI and 16S) to rapidly assess arthropod communities’ composition. Livestock removal quickly increased grass cover and arthropod taxonomic richness and diversity, which was already higher in short-term (1-year exclosures) than beneath the canopies of control trees. Interestingly, arthropod diversity was not highest at long-term exclosures (≥10 years), although their community composition was the most distinct. Also, regardless of treatment, we found that functional diversity strongly correlated with the vegetation structure, being higher at trees beneath which there was higher grass cover and taller herbs. Overall, the taxonomic diversity peak at short term exclosures would support the intermediate disturbance hypothesis, which relates it with the higher microhabitat heterogeneity at moderately disturbed areas. Thus, we propose a rotatory livestock management in dehesas: plots with increased grazing should co-exist with temporal short-term exclosures. Ideally, a few long-term excluded areas should be also kept for the singularity of their arthropod communities. This strategy would make possible the combination of biological pest control and arthropod conservation in Iberian dehesas.

The Use and Prospects of Nonlethal Methods in Entomology.

Arthropods are declining globally, and entomologists ought to be in the forefront of protecting them. However, entomological study methods are typically lethal, and we argue that this makes the ethical status of the profession precarious. Lethal methods are used in most studies, even those that aim to support arthropod conservation. Additionally, almost all collecting methods result in bycatch, and a first step toward less destructive research practices is to minimize bycatch and/or ensure its proper storage and use. In this review, we describe the available suite of nonlethal methods with the aim of promoting their use. We classify nonlethal methods into (a) reuse of already collected material, (b) methods that are damaging but not lethal, (c) methods that modify behavior, and (d) true nonlethal methods. Artificial intelligence and miniaturization will help to extend the nonlethal methodological toolkit, but the need for further method development and testing remains.

Arthropods are kin: Operationalizing Indigenous data sovereignty to respectfully utilize genomic data from Indigenous lands.

Indigenous peoples have cultivated biodiverse agroecosystems since time immemorial. The rise of metagenomics and high-throughput sequencing technologies in biodiversity studies has rapidly expanded the scale of data collection from these lands. A respectful approach to the data life cycle grounded in the sovereignty of indigenous communities is imperative to not perpetuate harm. In this paper, we operationalize an indigenous data sovereignty (IDS) framework to outline realistic considerations for genomic data that span data collection, governance, and communication. As a case study for this framework, we use arthropod genomic data collected from diversified and simplified farm sites close to and far from natural habitats within a historic Kānaka 'Ōiwi (Indigenous Hawaiian) agroecosystem. Diversified sites had the highest Operational Taxonomic Unit (OTU) richness for native and introduced arthropods. There may be a significant spillover effect between forest and farm sites, as farm sites near a natural habitat had higher OTU richness than those farther away. We also provide evidence that management factors such as the number of Polynesian crops cultivated may drive arthropod community composition. Through this case study, we emphasize the context-dependent opportunities and challenges for operationalizing IDS by utilizing participatory research methods, expanding novel data management tools through the Local Contexts Hub, and developing and nurturing community partnerships-all while highlighting the potential of agroecosystems for arthropod conservation. Overall, the workflow and the example presented here can help researchers take tangible steps to achieve IDS, which often seems elusive with the expanding use of genomic data.

Age of Eucalyptus plantations differentially affects assemblages of surface‐active arthropods

AbstractMicrohabitats 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.

Commercial banana and macadamia plantations in a savanna matrix support high levels of arthropod diversity

Expansion and intensification of agroecosystems is one of the major causes of habitat loss in the savanna biome in South Africa. As such, this study sought to determine the influence of commercial subtropical fruit plantations (banana and macadamia) on species richness, abundance, and composition of surface-active arthropods compared to the savanna biome. Given that pesticides and herbicides are applied from spring to early autumn in banana and macadamia plantations, we sampled in winter to reduce the potential impact of pesticides and herbicides. Surface-active arthropods were sampled using pitfall traps. Habitat type did not affect species richness and abundance of ants and spiders, as well as species richness of beetles. However, significantly greater abundance of beetles was recorded in the macadamia plantation compared to the banana and savanna. This could have been due to greater abundance of herbivorous beetles and other insects, which would have increased the diversity of predatory beetles. Furthermore, unlike the banana plantation, the macadamia plantation was characterised by a deep leaf litter layer and the presence of weeds and grasses, which probably increased abundance of beetles. Species composition indicated that the studied arthropod taxa associate with specific habitats, as demonstrated by the three habitats supporting different species composition. Despite savanna habitat not supporting high species richness or abundance of surface-active arthropods, we recorded the highest number of unique species of ants and spiders in the savanna rather than in the plantations. These results highlight the importance of natural landscapes in conservation of surface-active arthropods.

Differentiating the effects of organic management, pesticide reduction, and landscape diversification for arthropod conservation in viticulture

Biodiversity loss is a main challenge for agricultural sustainability. Major drivers include local management and landscape simplification. Therefore, conservation measures aim to increase organic agriculture, reduce pesticide use, and increase the proportion of semi-natural habitats (SNH). Yet, it is important to understand the effects of such measures. We investigate how arthropod biomass, taxa richness, and community composition in Malaise trap samples are affected by organic management, pesticide use, and SNH in the landscape. The 32 studied vineyards were chosen in a crossed design of management (organic vs. conventional) and pesticide use (regular vs. reduced) along a gradient of landscape composition. Pesticide reduction by 55% was obtained by including half of the vineyards with fungus-resistant grape (FRG) varieties. Malaise trap samples were weighed and arthropods identified using metabarcoding. Surprisingly, biomass was almost one-third higher in conventionally managed vineyards compared to organic ones. Taxa richness increased by more than one third when the proportion of SNH in a radius of 1,000 m in the surrounding landscape increased from zero to 50%. Diptera richness tended to be 4% higher in conventionally managed vineyards and the richness of Hymenoptera was 9% higher in FRG varieties. Community composition changed with the proportion of SNH and differed between organic and conventional management. Overall, organic viticulture was not effective to enhance the arthropod community, which was dominated by flying insects in our study. Agricultural policies should therefore rather preserve and promote SNH in the surrounding in order to promote arthropod biodiversity in viticultural landscapes.

Conservation-relevant plant species indicate arthropod richness across trophic levels: Habitat quality is more important than habitat amount

The massive declines in terrestrial arthropods reported across Europe call for effective methods to monitor and promote biodiversity in human-dominated landscapes. Previous studies vary in their support for the suitability of plants as indicators of arthropod diversity, while the potential of subsets of conservation-relevant plant species to estimate arthropod richness remains to be tested. Moreover, the relative importance of plant species richness compared to other factors driving arthropod richness, such as land-use intensity, habitat amount and landscape configuration, is poorly understood. We conducted a multi-scale field study in Southern Germany, sampling vascular plants and terrestrial arthropods in four local land-use types (forest, grassland, arable field, settlement) across large-scale gradients of climate and land-use intensity. We obtained an extensive arthropod dataset using Malaise traps as sampling method and DNA metabarcoding for species identification. We compared the correlation of three sets of plant species richness (total, red-listed and biotope-indicator plants) with arthropod richness, including different trophic and taxonomic groups. Using mixed-effect models, we assessed the partial effects of plant species richness, habitat amount and landscape configuration on local arthropod richness while controlling for climate and land-use effects, and explored the environmental drivers of plant species richness. Arthropod species numbers of all trophic groups strongly responded to species numbers of plants that indicate protected habitats, while red-listed plant species richness was a key determinant for the richness of red-listed arthropods and butterflies. In most cases, plant species richness and temperature were stronger drivers of arthropod richness than the amount of surrounding semi-natural habitat and landscape configuration. While total plant species richness was highest in settlements, the richness of biotope-indicator plants was highest in forests and positively influenced by the amount of semi-natural habitat and edge density. The number of red-listed plant species increased with edge density at the landscape scale but was independent of habitat amount. We conclude that the richness of conservation-relevant plant species provides a powerful indicator of arthropod diversity, and underpins the potential of such plant lists for monitoring habitat quality. Our study highlights the importance of openings in forests for conservation of plants and arthropods as well as of preserving and restoring fragments of high-quality biotopes in agricultural and urban areas where the amount of semi-natural habitat is limited.

Response of ants, beetles and spiders to disturbance varies among taxa in a South African savannah biome

Savannahs are structurally complex ecosystems consisting of a diverse community of plants and animals such as arthropods. Arthropods are essential in many ecosystem processes that help maintain life on Earth. The anthropogenic conversion of natural landscapes into croplands, residential and industrial areas has a negative impact on surface-active arthropods that have limited dispersal abilities and narrow habitat preferences. This study investigated the effect of disturbance on assemblages of ants, beetles and spiders in the savannah vegetation in Mpumalanga province, South Africa. We compared species richness, abundance and composition of these three taxa between the pristine savannah and the savannah that is exposed to a variety of anthropogenic activities (disturbed savannah). Arthropods were collected using pitfall traps in 15 sites in pristine savannah and 15 sites in disturbed savannah. We found that disturbance affects species richness and abundance of these taxa differently. Disturbance did not affect species richness of spiders and abundance of beetles, while greater species richness of ants and beetles, as well as abundance of ants and spiders was in disturbed than in pristine savannah. Furthermore, the species compositions of all taxa were different between disturbed and pristine savannah. The disturbed savannah had twice more unique indicator species than the pristine savannah. Differences in assemblages of arthropods between pristine and disturbed habitats suggest that it may be important to consider habitats in and outside protected areas in the conservation of arthropods, particularly in areas with greater percentage of natural and semi-natural landscapes occurring outside protected areas.

Vegetation increases abundances of ground and canopy arthropods in Mediterranean vineyards

The decline of arthropod populations observed in many parts of the world is a major component of the sixth mass extinction with intensive agriculture being one of its main drivers. Biodiversity-friendly farming practices are taking centre stage in the recovery process. In vineyards, vegetation cover is commonly used for production purposes, to reduce soil compaction by machinery use and soil erosion. Here we examined the effects of vegetation cover and soil management on the abundance of ground- (spiders, beetles, Hemiptera and harvestmen) and canopy-dwelling (wild bees, green lacewings, beetles and Hemiptera) arthropods in three categories of vineyards: (i) vineyards with no vegetation, (ii) partially vegetated (every second inter-row is vegetated) and (iii) all inter-rows are vegetated. We recorded a general positive effect of a decrease in soil perturbation intensity and corresponding higher vegetation cover on arthropod abundance. Plant species richness was the most important vegetation parameter, with a positive effect on spiders, harvestmen, hemipterans and beetles (ground and canopy) abundances. Using a path analysis, we also highlighted the central role of inter-row vegetation management in trophic and non-trophic relationships between vegetation and arthropods, and between arthropod groups. Our results demonstrate the benefits of a softer soil management preserving a diverse vegetation cover for the conservation of arthropods in Mediterranean vineyards.

What feeds onQuercus ilexL.? A biogeographical approach to studying trophic interactions in a Mediterranean keystone species

AbstractAimHolm oak (Quercus ilexL.) is regarded as a keystone plant species. Trophic interactions may affect the distribution and abundance of phytophagous species, but the number of arthropod species that use holm oak as a food resource and their levels of host specificity are not yet known. Here, we aimed to quantify these species, their feeding strategies and conservation status, the taxonomic relatedness in each trophic guild and their degree of host specificity on holm oak.LocationOur study covered the whole distribution area ofQ. ilexin the central‐western Mediterranean Basin.MethodsWe reviewed the existing literature and compiled information about all arthropod species that feed onQ. ilex, as well as their feeding strategies and conservation status. We also investigated the relationships between trophic guilds and the taxonomic relatedness of species, and assessed the degree of climatic niche overlap with holm oak.ResultsWe found that 605 species feed on seven different parts of the holm oak plant (i.e. feeding strategies). More than 90% of these species lack a conservation status assessment, and eight are threatened by human activities, either as vulnerable, endangered or critically endangered. A significant phylogenetic relationship was found between taxonomic relatedness and groups of arthropods that feed on the same part of the plant (i.e. trophic guilds). Twenty per cent of the species had similar niches, thereby indicating the potentially high host dependence of these species.Main conclusionsThis study highlights the significance of a keystone tree species for arthropod conservation and the need for further research into the distribution and conservation status of arthropod species in Mediterranean holm oak woodlands.

Small-scale traditional maize farming fosters greater arthropod diversity value than conventional maize farming

Globally insects are in decline, with the transformation of natural areas for agriculture one of the most important drivers of this decline. Yet, insects play an important role in regulating ecosystem services such as pollination, soil fertility and pest suppression, so their conservation within agricultural areas is critical. We examined comparative impacts of traditional small-scale low input farming versus large-scale conventional farming systems, and mono-cropped versus inter-cropped systems in Kenyan maize fields on predator, ant and herbivore arthropod species richness and composition. We also considered the value of hedgerows and percentage of surrounding maize cover for arthropod conservation. As expected, traditional farming retained higher herbivore species richness, evenness and abundance, as well as higher predator abundance compared to conventional farming. Percentage maize cover was positively correlated to ant species richness, predator and herbivore abundance, as well as determining species assemblage composition for ants and herbivores. Hedgerow volume and the comparison of mono- vs inter-cropping were important predictors for predator evenness. These results suggest that the low input farming systems retain far higher arthropod numbers, although this does not seem to be due to the use of intercropping on the farms. Rather it seems that hedgerows play an important role in maintaining arthropods. While higher maize coverage surrounding the farm increases the species and abundance of arthropods in the fields, this is most likely due to the high biotope fidelity of arthropods that specialize in open cropping systems such as maize fields.Implications for insect conservationThe results here are encouraging as the retention of culturally important farming techniques (i.e., the traditional Kenyan farmers) and small improvements, such as the retention of hedgerows, greatly promotes biodiversity in the farmlands.

Diversity and abundance of soil-litter arthropods and their relationships with soil physicochemical properties under different land uses in Rwanda

ABSTRACT Soil-litter arthropods are critical for ecosystem functioning and sensitive to land use change, and hence to the variations in soil physicochemical properties. The relationships between soil-litter arthropod communities and soil physicochemical properties, however, remain poorly studied in Rwanda. We explored the relationships between the families of soil-litter arthropods and soil properties in exotic and native tree species, and in varieties of coffee and banana plantations. Soil-litter arthropods were sampled by using Berlese funnels, hand sorting, and pitfall traps, and were identified to the family level. Soil cores were collected and analysed for soil pH, available phosphorus, total nitrogen, soil organic carbon, silt, clay and sand. A total of 3176 individuals of soil-litter arthropods were collected, identified and classified into 13 orders and 23 families. Higher abundance was found in soil and litter sampled in plots of native tree species and banana plantations compared to exotic tree species and coffee plantations. Higher diversity was found in plots of native and exotic tree species. The analysis of soil physicochemical properties indicated that native tree species offer suitable conditions of studied soil properties. The study of the relationships between the land use, soil properties and families of soil-litter arthropods indicated positive correlations and relationships mainly in native tree species. We conclude that forest with native tree species play an important role in the conservation of soil-litter arthropods and for maintenance of better soil conditions.

An overview of Neotropical arthropod conservation efforts using risk assessment lists

Neotropical efforts for arthropod conservation are still insufficient. Some species from the Neotropical region have been assessed by the IUCN Red List criteria (IRL), while others have been assessed using local red lists (LRLs). Unfortunately, these two lists are completely unconnected, even when they use similar criteria to evaluate extinction risks. Therefore, an overview of arthropod conservation using the IRL and LRLs to determine general and common patterns for arthropods in the Neotropical region is still missing, and this was the main goal of our study. The LRLs provided significant information about the species under threat in the Neotropical region, particularly on endemic ones. Both the IRL and LRLs determined that habitat loss (agricultural use land than more 50%) is the most critical threat of arthropod diversity in this region, but other main threats were also found. The conservation efforts for arthropods in Neotropical countries have been developed heterogeneously. Special efforts are necessary to countries without red lists as large countries, islands, or island-like bioregions. So far, the most threatened arthropod diversity in the Neotropical region belongs to the Caribbean islands. Insect conservation is not just about red-listing. It is also crucial to conduct conservation action as habitat management and restoration, citizen science or specific policy to fight the illegal trade. The integration of LRLs with the IRL helped identify common threats to arthropod conservation and also facilitated the macroscopic evaluation of this topic. It is crucial to conserve Neotropical arthropods to protect animal biodiversity. The homologation of the LRLs in the IUCN would increase the representation of endemic arthropods generating (1) an increase in funding for research and (2) for local conservation policies such as ecological restoration, and their use as bioindicators of environmental impact on investment projects in agriculture, mining, forestry, and urbanization.

Assessing the conservation and enhancement value of revegetated strips on arthropod assemblages in a pasture landscape

Examining population dynamics of arthropod communities in habitats neighboring arable lands is essential to understanding how agroecosystems can be engineered to enhance ecosystem services and contribute to sustainable intensification. Arthropods comprise the bulk of faunal biomass on farms, are taxonomically diverse, and are the main drivers of many ecosystem functions. This study aimed to compare arthropod assemblages in revegetated strips of native plants and exotic pastures, and examine taxa of beneficial arthropods in revegetated strips and adjacent pasture in early spring (September 2009) and mid-summer (December 2009–January 2010) on two farms in southeastern Gippsland, Victoria, Australia. Arthropod community assemblages were distinctly different between revegetated strips and adjacent pasture with the exception of functional groups in early spring. Several taxa of beneficial arthropods including Carabidae (ground beetles) and Syrphidae (hoverflies) were of similar abundance in the two habitats. Only Formicidae (ants) were of higher abundances in revegetated strips compared to adjacent pasture in both seasons. Five of the 10 ant genera present, seven spider families and Dolichopodidae flies (long-legged flies) were found exclusively in revegetated strips. Apidae (bees) and Tachinidae (tachinid flies) had higher abundances in revegetated strips compared to 80 m into the adjacent pasture in mid-summer. Lycosidae (wolf spiders) were more abundant along the edge of revegetated strips and 20 m into adjacent pasture compared to the center (core) of revegetated strips and 80 m into pasture. These results illustrate that beneficial arthropods use revegetated strips as refugia and that revegetated strips clearly enhanced biological conservation of arthropods in pasturelands. Relevance of findings to enhanced biological control is also discussed.

Impact of small-scale conservation management methods on spider assemblages in xeric grassland

Seminatural grasslands are among the most valuable habitats for arthropod conservation in Central Europe. The abandonment of traditional farming has caused these areas to become overgrown and homogeneous, thereby resulting in loss of arthropod biodiversity. This traditional farming therefore needs to be complemented by active conservation management methods. An important question is whether small-scale conservation management may support arthropod diversity and habitat specialists inhabiting abandoned seminatural grasslands. We investigated the effects of mowing, prescribed burning, mechanical turf disturbance, and absence of active management on species richness, functional diversity and composition, conservation value, abundance of Red List species, and assemblage composition of spiders. The management methods were applied on small-scale (4 × 5 m) patches in protected xeric grassland. Spiders were sampled using pitfall traps and sweeping during 2017 and 2018. A total of 11,634 specimens from 154 species were recorded, including many rare and threatened species. The temporal responses of spider assemblages to active conservation management depended on the particular group of spiders. Changes in assemblage composition and resulting shifts in the community weighted mean values were distinct in the second year of the experiment. Management had no significant effect on the species richness of ground-dwelling spiders. Mechanical turf disturbance shifted the assemblage composition of ground-dwelling spiders towards habitat generalist species. Vegetation-dwelling spiders had the highest species richness in unmanaged patches. Their functional diversity was lower in disturbed patches. Burnt patches supported species of conservation concern for both spider groups. Prescribed burning had positive results for most of the studied indicators. Nevertheless, mechanical turf disturbance had a rather negative effect on the spider assemblages. Our results indicate that even small, patch-like interventions with minimal costs can considerably support the valuable spider assemblages of xeric grassland in the intensified landscape of Central Europe.

Microbiomes are integral to conservation of parasitic arthropods

Parasitic arthropods have not typically been included in conservation and management strategies, possibly because the most well-known blood-feeding arthropods are associated with human and livestock disease. However, the vast majority of parasitic arthropods pose no threat to human health and instead contribute to the overall stability of communities to which they belong. The loss of parasitic arthropod biodiversity likely has repercussions for host health, population density, and community structure. The need for parasitic arthropod conservation is urgent given they represent the majority of parasitic animal biodiversity and environmental change is expected to pose a significant threat to their survival. We urge that microbial associations of host–parasitic arthropod assemblages be considered in conservation efforts. Parasitic arthropods are dependent on their microbial associates for development, nutrient acquisition, immune function, and reproduction. The microbiome also mediates the interactions between a parasitic arthropod and a host, and the role of a parasitic arthropod in vectoring pathogens to its host. The microbiome may therefore represent a “weak link” that increases the susceptibility of parasitic arthropods to environmental change. Fundamental knowledge is missing, precluding assessment of this complex association between microbes and parasitic arthropods. We highlight broad areas of future research that focus on building primary knowledge, developing experimental protocols and novel statistics, and leveraging new techniques to increase the resolution at which we can examine microbial communities of parasites. Conservation of parasitic arthropods that accounts for microbiota will likely be more effective at maintaining parasite biodiversity and at controlling arthropod-vectored disease emergence.

Vegetated roofs in boreal climate support mobile open habitat arthropods, with differentiation between meadow and succulent roofs

Vegetated roofs are hoped to benefit urban wildlife, yet there are few empirical results regarding the conservation potential of such roofs. In this paper, we focus on arthropods on vegetated roofs. We vacuum sampled 17 succulent, meadow or succulent-meadow roofs, in Helsinki, Finland, and used order to species level information together with trait data to describe the communities. We evaluated the importance of biophysical roof characteristics on shaping arthropod assemblages to provide information concerning roof designs that promote rich arthropod fauna. Arthropod communities differed between the three roof types and the influence of roof variables varied between and within arthropod orders. The main local drivers of arthropod abundance across the individually analysed taxa were roof height and vegetation, with mainly positive effects of height (up to 11 m) and litter cover, and mainly negative effects of grass cover. Based on trait data from true bugs, spiders and ants, the roofs consisted mainly of common dispersive species that are generalist feeders and associated with dry open habitats or have wide habitat tolerance. We found one true bug species new to the country and assume that it arrived with imported vegetation. Based on these findings, vegetated roofs of varying height and size benefit common generalists and fauna of open dry habitats, but seem to lack rare native specialists and may introduce non-natives if imported plant material is used. Because the responses to vegetation characteristics are taxon-specific, high diversity of roof vegetation types would benefit arthropod conservation.

Arthropod biodiversity and conservation biological control in rice

Rice ecosystems have a rich and diverse fauna of arthropods which varied in field in different ecological conditions. Beside the phytophages and detritivores, a large number of predators and parasitoids also exist in the rice ecosystem. Biological control has shown a great potential for reducing the dependence of crop protection on chemical control. Among the predators, spiders are highly abundant in rice fields which feed on variety of insect pests. The organisms present in the rice ecosystem are linked by food web which can help IPM because they clarify the functional interaction between populations. Conservation biological control can be achieved by reducing the pesticide-induces mortality of natural enemies and habitat manipulation to improve natural enemies fitness and effectiveness in the rice fields. There is a plethora of natural enemies in rice ecosystem and conservation biological control plays a major role in reducing pests. The identification of safer chemical pesticides and supplemental food of natural enemies is still needed.

Known and unknown terrestrial arthropod fauna of La Réunion Island, Indian Ocean

A major part of La Reunion Island has been included on the World Heritage List of the United Nations Educational, Scientific and Cultural Organization (UNESCO) for its unique landscapes and its outstanding biodiversity. However, there is a lack of knowledge on the arthropod diversity. For this reason, an up-to-date census of Reunion’s terrestrial arthropods was undertaken. Of the 3369 species that are reported from Reunion, 31% are endemic to the island and 40% are endemic to the Mascarenes. A diversity ratio between the numbers of described and expected species in the world was established and then applied to the numbers of reported species in Reunion to estimate the total expected numbers of species on the island. The results predict that between 6751 and 10,812 species of terrestrial arthropods are present in Reunion and that 62% of species remain to be discovered. However, some groups appear underrepresented as expected for Darwinian islands that should be originally composed by species with abilities to colonize remote places. Considering the global biodiversity decline and the numerous threats on Reunion’s natural habitats, this article emphasizes the crucial need for conservation of terrestrial arthropods and strongly encourages an increase in the list of protected arthropods.

Floral abundance and richness drive beneficial arthropod conservation and biological control on golf courses

Golf courses are among the largest, most ubiquitous highly maintained urban green spaces in the U.S. Although their primary function is recreation, a large portion of golf course land is not actively in use, which presents opportunities to create more ecologically functional areas. Golf courses around the world are converting these out-of-play areas to alternative habitats, but few do so using evidence that maximizes their benefit. Previous studies have investigated effects of conservation plantings on golf courses, but none have isolated the biological control services of flying natural enemies and few investigated effects on native bees. In this study, we ask if converting out-of-play maintained turfgrass areas into wildflower habitats increases bee and insect natural enemy abundance and diversity and their associated ecosystem services. We created wildflower habitats at two levels of species richness and compared their effects on insects within and around them to turfgrass plots. To quantify effects on biological control, we deployed sentinel prey Spodoptera frugiperda larvae, excluding ground-dwelling predators. As predicted, we found that converting turfgrasses to flowering habitats increased bees and natural enemies on golf courses. However, high wildflower species richness was an important factor in promoting native bees and natural enemies. We found that wildflower habitats, particularly those with highest floral richness, increased biological control rates in adjacent turfgrass areas by up to 50% compared to turfgrass controls. Our results indicate that purposefully designed conservation plantings on golf courses can help support insect pollinators while also augmenting biological control of turfgrass pests.