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Bees provide pollination services in both agricultural and natural ecosystems. However, invasive ants that exploit floral nectar in these landscapes can compete with bees for resources, with implications for pollinator resource acquisition, plant fitness, and, ultimately, ecosystem function. While interference competition has been described between bees and nectivorous, non-pollinator antagonists, the behaviors and sensory mechanisms involved remain largely unresolved. Here, we studied the mechanisms by which invasive Argentine ants influence bee nectar foraging behavior. In a series of laboratory assays, we assessed the foraging behavior of bumble bees (Bombus impatiens) in response to live Argentine ants (Linepithema humile) or to a subset of ant chemical cues. Bees were clearly deterred by live ants at a nectar source: they consumed less, fed less frequently, and fed for a shorter duration when live ants were present. Bees were also deterred by a combination of olfactory and gustatory ant chemical cues, consistent with both innate and learned avoidance behavior. Naïve and ant-experienced bees were deterred through chemosensation of ants, feeding less from nectar infused with ant chemicals as compared to nectar lacking ants or their associated cues. Some ant-experienced bees showed a unique behavior, displaying aggression toward ants as well as in response to ant chemicals. The marked effects of this invasive ant on bee foraging behavior—through physical interaction and chemical cues—highlights Argentine ants as a serious pest whose control should be considered when developing pollinator conservation and management strategies. [ABSTRACT FROM AUTHOR]

" Adult Butterfly Feeding-Nectar Flower Associations: Constraints of Taxonomic Affiliation, Butterfly, and Nectar Flower Morphology." Nectar feeding without pollination is sometimes referred to as nectar thievery (Inouye, [9]), nectar robbing (e.g., Agrawal et al., [1]; Bauder et al., [3]), or ineffective legitimate visitation (Castro et al., [4]). Keywords: butterflies; Lycaenidae; nectar larceny; nectar robbing; Penstemon EN butterflies Lycaenidae nectar larceny nectar robbing Penstemon 1 5 5 02/03/23 20230201 NES 230201 The relationships between Lepidoptera and plants are complicated. [Extracted from the article]

In human-modified landscapes, understanding how habitat characteristics influence the diversity and composition of beneficial organisms is critical to conservation efforts and modeling ecosystem services. Assessing turnover, or the magnitude of change in species composition across sites or through time, is crucial to said efforts, yet is often overlooked. For pollinators such as wild bees, variables influencing temporal turnover, particularly across seasons within a year, remain poorly understood. To investigate how local and landscape characteristics correlate with bee diversity and turnover across seasons, we recorded wild bee and flowering ornamental plant assemblages at 13 plant nurseries in California between spring and autumn over 2 years. Nurseries cultivate a broad diversity of flowering plant species that differ widely across sites and seasons, providing an opportunity to test for correlations between turnover and diversity of plants and bees. As expected, we documented strong seasonal trends in wild bee diversity and composition. We found that local habitat factors, such as increased cultivation of native plants, were positively associated with bee diversity in sweep netting collections, whereas we detected moderate influences of landscape level factors such as proportion of surrounding natural area in passive trap collections. We also detected a moderate positive correlation between the magnitude of turnover in plant species and that of bee species (as number of taxa gained) across consecutive seasons. Our results have implications for the conservation of wild bees in ornamental plant landscapes, and highlight the utility of plant nurseries for investigating hypotheses related to diversity and turnover in plant–pollinator systems. [ABSTRACT FROM AUTHOR]

Bees used alfalfa leaves but ignored alfalfa petals and cut marigold petals but not marigold leaves. Relative to the abundance of plants in cages, bees used alfalfa leaves, marigold petals, and mallow leaves 4.8, 8.9, and 6.1 times more than expected, respectively, but used mallow petals 1.9 times less than expected (Fig. Keywords: alfalfa leafcutting bee; behavior; Medicago sativa; Megachile rotundata; Megachilidae; reproduction EN alfalfa leafcutting bee behavior Medicago sativa Megachile rotundata Megachilidae reproduction 1 4 4 02/03/22 20220201 NES 220201 The alfalfa leafcutter bee ( I Megachile rotundata i , hereafter simply "leafcutter bee") is a solitary, cavity-nesting bee native to Eurasia, managed as an agricultural pollinator of alfalfa and several other crops in North America since the 1940s (Pitts-Singer and Cane 2011). Here, we describe the petal provisioning behavior and provide the first, to our knowledge, quantitative assessment of behavior related to leafcutter bee nest building material selection involving petals in a controlled environment. [Extracted from the article]

Hummingbirds, a highly diverse avian family, are specialized vertebrate pollinators that feed upon carbohydraterich nectar to fuel their fast metabolism while consuming invertebrates to obtain protein. Previous work has found that morphologically diverse hummingbird communities exhibit higher diet specialization on floral resources than morphologically similar hummingbird communities. Due to the difficulties of studying avian diets, we have little understanding whether hummingbirds show similar patterns with their invertebrate prey. Here, we use DNA metabarcoding to analyze floral and invertebrate diets of 3 species of sympatric North American hummingbirds. We collected fecal samples from 89 Anna’s (Calypte anna), 39 Black-chinned (Archilochus alexandri), and 29 Calliope (Selasphorus calliope) hummingbirds in urban and rural localities as well as across an elevational gradient from sea level to 2,500 meters above sea level in California, USA. We found hummingbirds showed high dietary overlap in both invertebrate and plant resources, with few invertebrate and plant families common to most individuals and many families found in only a few individuals. Chironomidae was the most common invertebrate family across all species, and Rosaceae and Orobanchaceae were the most common plant families. Anna’s Hummingbirds had significantly higher invertebrate diet diversity than Black-chinned Hummingbirds when found at the same sites, but we found no difference in plant diet diversity among any of the 3 species. Hummingbirds in urban sites had higher plant diet diversity than in rural sites, but we found no effect of elevation on dietary richness. Our study shows how DNA metabarcoding can be used to non-invasively investigate previously unknown life-histories of well-studied birds, lending insight to community structure, function, and evolution. [ABSTRACT FROM AUTHOR]

1. An ongoing challenge in ecology is predicting how characteristics of communities correspond to habitat features. Examining variation in functional traits across species may reveal patterns not discernible from measures of mere abundance or richness. For beneficial insects like wild bees, functional trait‐based approaches are often used to characterise communities in different agricultural habitats. 2. However, no such approach has yet been applied in horticultural plant nurseries, which represent intensively managed artificial flowering plant assemblages. Certain nurseries mostly cultivate regionally native flowering plants, allowing one to test how differences between local plant assemblages may correlate with bee functional traits. 3. We surveyed bee assemblages at native and conventional plant nurseries in southern California from spring through autumn over 2 years, while also documenting the native status of blooming plants in sampling plots. Bees were classified into different functional categories based on their diet breadth, nesting location, and social organisation. 4. At native plant nurseries, we netted proportionally more specialist bee species and fewer generalist species than at conventional nurseries. Nesting location and social organisation of bee samples did not differ between nursery types. Meanwhile, landscape‐level features were not associated with any observed functional trait metrics of bee collections. Furthermore, network‐level specialisation of bee‐plant interactions was higher at conventional nurseries. 5. Our results suggest that a horticultural cultivation practice is quantifiably correlated with the functional distribution of resident bee assemblages. These results are important and encouraging to pollinator conservation efforts in nursery systems and other human‐modified landscapes dominated by ornamental plants. [ABSTRACT FROM AUTHOR]

Social insect colonies exhibit a variety of life history strategies, from the annual, semelparous colonies of temperate bees and wasps to the long-lived colonies of many ants and honeybees. Species introduced to novel habitats may exhibit plasticity in life history strategies as a result of the introduction, but the factors governing these changes often remain obscure. Vespula pensylvanica, a yellowjacket wasp, exhibits such plasticity in colony longevity. Multi-year (perennial) colonies are relatively common in introduced populations in Hawaii, while source populations in the western United States are typically on an annual cycle. Here, we use experiments and observational data to examine how diet, disease, nest thermal environment, and nest location influence colony longevity in a population with both annual and perennial colonies. Counter to our predictions, experimental feeding and warming did not increase colony survival in the winter in the introduced range. However, Moku Virus load and wasp colony density predicted colony survival in one year, suggesting a potential role for disease in modulating colony phenology. We also found that local V. pensylvanica colony density was positively correlated with Moku Virus loads, and that Arsenophonus sp. bacterial loads in V. pensylvanica colonies were positively associated with proximity to feral honeybee (Apis mellifera) hives, suggesting potential transmission routes for these poorly understood symbionts. The factors influencing colony longevity in this population are likely multiple and interactive. More important than food availability, we propose winter precipitation as a critical factor that may explain temporal and spatial variation in colony longevity in these invasive wasps. [ABSTRACT FROM AUTHOR]

Pollinators such as bees need reliable access to nectar resources. However, competition for these carbohydrate rewards can be high among floral visitors. Moreover, invasive insects may further restrict pollinator access to flowers. For example, invasive Argentine ants (Linepithema humile) are known to harass and displace pollinators from flowers and reduce nectar reward acquisition. The foraging behavior of bees is strongly influenced by numerous chemical cues and signals at the flower. Thus, to avoid aggressive floral visitors, bees may use chemical cues when deciding whether or not they forage on the flower. Here, we demonstrate that Argentine ants deposit a pygidial gland chemical, iridomyrmecin, on a sugar source while feeding. Based on two-choice laboratory assays conducted with three commercially available bee species, the presence of iridomyrmecin in the sugar resource influenced the foraging decisions of Megachile rotundata and Osmia lignaria, but not those of Apis mellifera. Detailed insights into the chemical signals left by ants at floral resources and their effects on foraging decisions by pollinators can provide vital information for understanding the magnitude and mechanisms of impacts invasive ant species might have on pollinators. [ABSTRACT FROM AUTHOR]

Mark-recapture experiments reveal foraging behavior and plant fidelity of native bees in plant nurseries Keywords: agroecosystems; California; foraging fidelity; Halictus; native plants; ornamental plants EN agroecosystems California foraging fidelity Halictus native plants ornamental plants 1 4 4 06/04/20 20200601 NES 200601 Understanding the spatial and temporal foraging patterns of pollinators is essential to conserving these organisms in human-modified landscapes, such as agroecosystems (Cranmer et al. [3]). These bees not only foraged in the same general location the next day, but of the 106 recaptured bees, 102 (96.2%) foraged on the same plant species as the previous day despite the broad diversity of plants flowering in nurseries. Although more bees were recaptured on native plants overall, some bees still displayed relatively high rates of fidelity to nonnative plants, though we found no preference for or against any nonnative plant species. [Extracted from the article]

Worldwide, native species increasingly contend with the interacting stressors of habitat fragmentation and invasive species, yet their combined effects have rarely been examined. Direct negative effects of invasive omnivores are well documented, but the indirect effects of resource competition or those caused by predator avoidance are unknown. Here we isolated and examined the independent and interactive effects of invasive omnivorous Black rats (Rattus rattus) and forest fragment size on the interactions between avian predators and their arthropod prey. Our study examines whether invasive omnivores and ecosystem fragment size impact: 1) the vertical distribution of arthropod species composition and abundance, and 2) the vertical profile of foraging behaviors of five native and two non-native bird species found in our study system. We predicted that the reduced edge effects and greater structural complexity and canopy height of larger fragments would limit the total and proportional habitat space frequented by rats and thus limit their impact on both arthropod biomass and birds’ foraging behavior. We experimentally removed invasive omnivorous Black rats across a 100-fold (0.1 to 12 ha) size gradient of forest fragments on Hawai‘i Island, and paired foraging observations of forest passerines with arthropod sampling in the 16 rat-removed and 18 control fragments. Rat removal was associated with shifts in the vertical distribution of arthropod biomass, irrespective of fragment size. Bird foraging behavior mirrored this shift, and the impact of rat removal was greater for birds that primarily eat fruit and insects compared with those that consume nectar. Evidence from this model study system indicates that invasive rats indirectly alter the feeding behavior of native birds, and consequently impact multiple trophic levels. This study suggests that native species can modify their foraging behavior in response to invasive species removal and presumably arrival through behavioral plasticity. [ABSTRACT FROM AUTHOR]

Invasive predators can profoundly impact native communities, especially in insular ecosystems where functionally equivalent predators were evolutionarily absent. Beyond direct consumption, predators can affect communities indirectly by creating or altering food web linkages among existing species. Where invasive predators consume prey from multiple distinct resource channels, novel links may couple the dynamics of disjunct modules and create indirect interactions between them. Our study focuses on invasive populations of Eleutherodactylus coqui (Anura: Leptodactylidae) on Hawaii Island. Coqui actively forage in the understory and lower canopy at night but return to the forest floor and belowground retreats by day. Recent dietary studies using gut contents and naturally occurring stable isotopes indicate higher than expected consumption of litter arthropods, which in these Hawaiian forests are primarily non-native species. We used laboratory studies to observe diurnal and nocturnal foraging behavior, and experimental field additions of C4 vegetation as a litter tracer to distinguish epigaeic sources from food web pools in the C3 canopy. Lab trials revealed that prey consumption during diurnal foraging was half that consumed during nocturnal foraging. Analysis of δ13C isotopes showed incorporation of C4 carbon into litter arthropods within one month, and Bayesian mixing models estimated that 15–25% of the carbon in coqui tissue was derived from litter sources. These results support recent findings that E. coqui are not quiescent diurnally but instead actively forage. Such activity by a mobile invasive predator may introduce a novel linkage that integrates detrital and foliar resource pools, potentially distributing influences of invasive litter arthropods through the broader system to amplify impacts on native species. [ABSTRACT FROM AUTHOR]

In eusocial insects, nestmate queens can differ in their reproductive output, causing asymmetries in the distribution of mutual benefits. However, little is known about how reproductive success is partitioned in incipiently polygynous species, which would provide clues about the evolutionary forces shaping the emergence of polygyny. Here, we leverage a recent transition from predominantly single-queen (monogyne) to multiple-queen (polygyne) colonies in an invasive yellowjacket species to investigate whether queens in incipiently polygyne colonies invest equally in reproductive effort or vary in their relative investment in each caste. We excavated nine polygyne Vespula pensylvanica colonies in Hawaii and used restriction site–associated DNA sequencing to infer the parentage of worker, male, and gyne (daughter queen) pupae from each nest comb. In four colonies with at least eight gyne pupae, a single queen produced most or all gynes. These queens had no male offspring and few worker offspring, suggesting that a subset of nestmate queens might exploit the collective benefits of newly polygyne societies. In contrast to most queens, gyne producers had offspring distributed nonrandomly across nest combs. Nestmate queens generally exhibited low relatedness levels. Our results suggest that rapid, ecologically driven transitions to polygyny among unrelated queens may, at their onset, be vulnerable to reproductive asymmetries that are likely evolutionarily unstable. More broadly, this study contributes to the understanding of social evolution by uncovering asymmetric partitioning of reproduction in a population with newly evolved polygyny and raises questions about the future trajectories of introduced populations. [ABSTRACT FROM AUTHOR]

Social wasps play critical ecological roles in an ecosystem, providing a diversity of services and some disservices. Yellowjacket wasps (Vespula spp.) in particular are well known for shaping arthropod communities via predation and competition for resources. In part due to their sociality and large colony sizes, Vespula can have a profound ecological impact on local communities. Such effects can be magnified when colonies exhibit a perennial life history, in which a colony will overwinter, persist for more than one year, and become orders of magnitude larger in size compared to typical annual colonies. Despite growing interest in the factors that influence colony success, we currently lack the ability to predict when yellowjackets may have a high-abundance or outbreak year. This highlights the need for a critical understanding of the phenological patterns of foraging activity, colony distribution, and senescence. Here, we quantify the seasonal activity and foraging rates of 123 colonies of the western yellowjacket, V. pensylvanica, in its native range over 4 consecutive years. Average colony longevity was about 1 month longer than previously reported for this species, and colonies with later peaks in activity and higher average traffic rates persisted longer into the winter. Longer-lived colonies tended to cluster together within a year, but not between years. We found 3 perennial colonies (2.4% of all colonies), and they exhibited tenfold higher peak traffic rates compared to annual colonies. By identifying temporal and spatial patterns in survivorship and colony longevity, we gain insight into the factors associated with prolonged survival time and increased likelihood of overwintering in yellowjacket wasps. [ABSTRACT FROM AUTHOR]

Understanding the pollination requirements of threatened species is critical for the success of longterm conservation strategies. In a series of greenhouse experiments, we assessed the effects of different pollination treatments, including autogamy, facilitated autogamy, and cross-pollination on fruit and seed set for 2 generations of a rare island endemic plant. Santa Cruz Island rockcress, Sibara filifolia (Brassicaceae), is a rare, endangered annual herb that is endemic to the California Channel Islands. While efforts are underway to monitor and conserve this rare plant species, little is known about its pollination biology. We quantified the index of self-compatibility and multiplicative fitness. We also assessed how maternal plant treatment influenced seed germination and seedling survival rates. While S. filifolia is fully self-compatible, we demonstrate that facilitated pollination and outcrossing treatments positively affected all measures of reproductive output and fitness in first-generation plants. Metrics of predispersal fitness (e.g., fruit set and seed production) in the F2 generation also increased significantly in response to facilitated pollination and outcrossing. While our data suggest that S. filifolia fecundity increases with outcrossing, we observed lower fitness benefits of facilitated autogamy and outcrossing on the production of F2 seeds. This highlights the difficulty in providing specific recommendations when the consequences of outbreeding may not be detectable until later generations. More study is required to confirm that multiple generations of interpopulation gene flow can effectively improve population viability and decrease genetic erosion. [ABSTRACT FROM AUTHOR]

Birds increase crop yields via consumption of pests in some contexts but disrupt pest control via intraguild predation in others. Landscape complexity acts as an inconsistent mediator, sometimes increasing, decreasing, or not impacting pest control. Here, we examined how landscape context and seasonal variation mediate the impact of birds on arthropod pests and natural enemies, leaf damage, and yields of broccoli (Brassica oleracea) on highly diversified farms that spanned the USA west coast. Our study had two complementary components: a bird exclusion experiment and molecular diet analysis of 357 fecal samples collected from the most commonly captured bird species that also foraged in Brassica fields--American Goldfinch (Spinus tristis), American Robin (Turdus migratorius), Savannah Sparrow (Passerculus sandwichensis), Song Sparrow (Melospiza melodia), and White-crowned Sparrow (Zonotrichia leucophrys). Bird access yielded higher, rather than lower, numbers of pest aphids and increased their parasitism, while no other arthropods examined were consistently impacted. Independent of bird presence, percent natural cover in the landscape sometimes increased and sometimes decreased densities of arthropods in the mid-growth period, with diminishing impacts in the late-growth period. Herbivore feeding damage to broccoli leaves decreased with increasing amounts of natural land cover and in the late-growth period. Molecular diet analysis revealed that Brassica pests and predatory arthropods were relatively uncommon prey for birds. Landscape context did not alter the prey items found in bird diets. Altogether, our bird-exclusion experiment and molecular diet analysis suggested that birds have relatively modest impacts on the arthropods associated with broccoli plantings. More broadly, the limited support in our study for net natural pest control services suggests that financial incentives may be required to encourage the adoption of bird-friendly farming practices in certain cropping systems. [ABSTRACT FROM AUTHOR]

Farmland birds can suppress insect pests, but may also consume beneficial insects, damage crops and potentially carry foodborne pathogens. As bird communities shift in response to farming practices, so too do the benefits (services) and costs (disservices) from birds. Understanding how and why ecosystem services and disservices covary can inform management interventions that enhance synergies, avoid trade‐offs and promote multifunctionality.We investigated how farmland diversification practices influence the services and disservices provided by wild birds on 21 California strawberry farms. Specifically, we coupled 285 bird surveys, metabarcoding and other molecular analyses of ~1,000 faecal samples representing 55 bird species (mostly passerines) to determine which individuals consumed pests, natural enemies, and crops and carried foodborne pathogens. Then, we explored how farming practices shape ecosystem service bundles, or suites of consistently co‐occurring services/disservices.Avian services and disservices were shaped by interactions between local farming practices and landscape context. We found that the amount of semi‐natural habitat surrounding each farm was the single most important driver of ecosystem services, with the best outcomes (highest multifunctionality) occurring on farms surrounded by semi‐natural habitat.Bundles were primarily influenced by landscape context. Increasing semi‐natural habitat around farms was associated with more multifunctional bird communities that maximized services and minimized disservices. However, not all trade‐offs were minimized in landscapes with more semi‐natural habitat, suggesting that specific farming contexts can exacerbate or mitigate trade‐offs as bird communities shift in response to diversification practices.Synthesis and applications. Though growers are often pressured to remove non‐crop habitat to reduce food‐safety risks, our work suggests that conserving habitat can support bird conservation, mitigate food‐safety risks and decrease crop damage from birds. More broadly, by considering the multiple roles that communities play in ecosystems, managers can simultaneously maximize services and minimize disservices to achieve multifunctionality. [ABSTRACT FROM AUTHOR]

Birds play many roles within agroecosystems including as consumers of crops and pests, carriers of pathogens and beloved icons. Birds are also rapidly declining across North America, in part due to agricultural intensification. Thus, it is imperative to identify how to manage agroecosystems to best support birds for multi‐functional outcomes (e.g. crop production and conservation). Both the average amounts of services/disservices provided and their temporal stability are important for effective farm planning.Here, we conducted point count surveys for 4 years across 106 locations on 27 diversified farms in Washington and Oregon, USA. We classified birds as ecosystem service or disservice providers using indices spanning supporting, regulating, provisioning and cultural services/disservices. We then examined service/disservice index pairwise correlations and assessed the relative importance of local, farm and landscape complexity on the average and temporal stability of avian service/disservice provider indices.Generally, service provider indices (production benefitting birds, grower appreciation and conservation scores) were positively correlated with each other. Foodborne pathogen risk, grower disapproval and identity/iconic value indices were also positively correlated with each other. However, the crop damaging bird index generally had low correlations with other indices.Farms that implemented more conservation‐friendly management practices generally had higher average service provider indices, but farm management did not impact disservice provider indices, except for grower disapproval. Average disservice provider indices were lower on farms in complex landscapes.Local vertical vegetation complexity tended to increase the temporal stability of service provider indices but did not affect the disservice provider indices. Greater landscape complexity was generally associated with increased temporal stability of service and disservice provider indices. Increased landscape complexity may stabilize bird communities by increasing bird community evenness, which in turn, positively predicted temporal stability of all service/disservice provider indices.Policy implications. Our results suggest that farmers can effectively manage their farms to harness ecosystem services from birds through farm diversification. Disservices provided by birds, however, appear to be most negatively impacted by landscape‐level complexity. Thus, greater incentives for farmers to increase semi‐natural cover at the landscape scale are likely necessary to achieve multifunctional outcomes for conservation and agriculture. [ABSTRACT FROM AUTHOR]

Summary: Introduced mammalian predators are responsible for the decline and extinction of many native species, with rats (genus Rattus) being among the most widespread and damaging invaders worldwide. In a naturally fragmented landscape, we demonstrate the multi-year effectiveness of snap traps in the removal of Rattus rattus and Rattus exulans from lava-surrounded forest fragments ranging in size from <0.1 to >10 ha. Relative to other studies, we observed low levels of fragment recolonization. Larger rats were the first to be trapped, with the average size of trapped rats decreasing over time. Rat removal led to distinct shifts in the foraging height and location of mongooses and mice, emphasizing the need to focus control efforts on multiple invasive species at once. Furthermore, because of a specially designed trap casing, we observed low non-target capture rates, suggesting that on Hawai'i and similar islands lacking native rodents the risk of killing non-target species in snap traps may be lower than the application of rodenticides, which have the potential to contaminate food webs. These efforts demonstrate that targeted snap-trapping is an effective removal method for invasive rats in fragmented habitats and that, where used, monitoring of recolonization should be included as part of a comprehensive biodiversity management strategy. [ABSTRACT FROM AUTHOR]

Invasive species present a worldwide concern as competition and pathogen reservoirs for native species. Specifically, the invasive social wasp, Vespula pensylvanica, is native to western North America and has become naturalized in Hawaii, where it exerts pressures on native arthropod communities as a competitor and predator. As invasive species may alter the microbial and disease ecology of their introduced ranges, there is a need to understand the microbiomes and virology of social wasps. We used 16S rRNA gene sequencing to characterize the microbiome of V. pensylvanica samples pooled by colony across two geographically distinct ranges and found that wasps generally associate with taxa within the bacterial genera Fructobacillus, Fructilactobacillus, Lactococcus, Leuconostoc, and Zymobacter, and likely associate with environmentally-acquired bacteria. Furthermore, V. pensylvanica harbors—and in some cases were dominated by—many endosymbionts including Wolbachia, Sodalis, Arsenophonus, and Rickettsia, and were found to contain bee-associated taxa, likely due to scavenging on or predation upon honey bees. Next, we used reverse-transcriptase quantitative PCR to assay colony-level infection intensity for Moku virus (family: Iflaviridae), a recently-described disease that is known to infect multiple Hymenopteran species. While Moku virus was prevalent and in high titer, it did not associate with microbial diversity, indicating that the microbiome may not directly interact with Moku virus in V. pensylvanica in meaningful ways. Collectively, our results suggest that the invasive social wasp V. pensylvanica associates with a simple microbiome, may be infected with putative endosymbionts, likely acquires bacterial taxa from the environment and diet, and is often infected with Moku virus. Our results suggest that V. pensylvanica, like other invasive social insects, has the potential to act as a reservoir for bacteria pathogenic to other pollinators, though this requires experimental demonstration. [ABSTRACT FROM AUTHOR]

Social wasps of the genus Vespula have spread to nearly all landmasses worldwide and have become significant pests in their introduced ranges, affecting economies and biodiversity. Comprehensive genome assemblies and annotations for these species are required to develop the next generation of control strategies and monitor existing chemical control. We sequenced and annotated the genomes of the common wasp (Vespula vulgaris), German wasp (Vespula germanica), and the western yellowjacket (Vespula pensylvanica). Our chromosome-level Vespula assemblies each contain 176–179 Mb of total sequence assembled into 25 scaffolds, with 10–200 unanchored scaffolds, and 16,566–18,948 genes. We annotated gene sets relevant to the applied management of invasive wasp populations, including genes associated with spermatogenesis and development, pesticide resistance, olfactory receptors, immunity and venom. These genomes provide evidence for active DNA methylation in Vespidae and tandem duplications of venom genes. Our genomic resources will contribute to the development of next-generation control strategies, and monitoring potential resistance to chemical control. [ABSTRACT FROM AUTHOR]

Agricultural intensification and expansion have degraded biodiversity in agroecosystems, jeopardizing the ecosystem services provided by wildlife. Birds can act as particularly important purveyors of ecosystem services to farmers by consuming arthropod pests. Some bird species, however, may sometimes act as pests themselves by consuming crops. Further, on-farm management practices (e.g., crop diversity, vegetative structure) and the complexity of the surrounding landscape can shift the balance of bird-mediated ecosystem services and disservices through changes in bird community composition. Here, we explored how organic strawberry farms in California could be managed to bolster bird biodiversity and shift community composition from strawberry-consuming to pest-eating species. Using multi-species N-mixture models we found that semi-natural habitat at the landscape (1000 m) and farm (50 m) scales were positively associated with mean abundance of all birds, with varying effects on different species. In particular, we found that the mean local abundance of species that consume Lygus spp. (a major pest), but not strawberry-consuming species, increased with semi-natural habitat at the farm scale. Nest density in developed areas within farms also increased with greater semi-natural habitat in the landscape, while nest density in semi-natural habitat within farms decreased with increasing semi-natural habitat in the landscape. Further, nest density of Lygus spp. eating birds increased with increasing local semi-natural habitat. These results suggest that increasing semi-natural habitat at the landscape and local scales can bolster bird abundance across farms, while pest control can be promoted locally by conserving or restoring semi-natural vegetation at the farm scale. • We paired bird surveys with molecular diet data to identify key ecosystem service/disservice providers of strawberry farms. • N-mixture models show that community-wide bird abundance responds to seminatural habitat at local and landscape scales. • Birds that consume Lygus increase with local seminatural habitat, suggesting local seminatural habitat promotes biocontrol. [ABSTRACT FROM AUTHOR]

Using molecular tools, we identify Grammia ursina Schmidt, 2009 to be present at high densities on San Clemente Island, California. As a generalist herbivore, G. ursina has many hosts and is a potential pest of rare and endemic plants. We present a list of host records of G. ursina, including rare plants on San Clemente Island. Conservation efforts to support rare plants on the island include outplantings, which have been negatively affected in G. ursina outbreaks. We suggest continual monitoring of G. ursina populations to predict future outbreaks and population peaks and to monitor its effects on endemic plant species and restoration efforts. [ABSTRACT FROM AUTHOR]