Search

We investigated the plant‐pollinator interactions of the Mexican grass‐carrying wasp Isodontia mexicana—native to North America and introduced in Europe in the 1960s—through the use of secondary data from citizen science observations. We applied a novel data exchange workflow from two global citizen science platforms, iNaturalist and Pl@ntNet. Images from iNaturalist of the wasp were used to query the Pl@ntNet application to identify possible plant species present in the pictures. Simultaneously, botanists manually identified the plants at family, genus and species levels and additionally documented flower color and biotic interactions. The goals were to calibrate Pl@ntNet's accuracy in relation to this workflow, update the list of plant species that I. mexicana visits as well as its flower color preferences in its native and introduced ranges. In addition, we investigated the types and corresponding frequencies of other biotic interactions incidentally captured on the citizen scientists' images. Although the list of known host plants could be expanded, identifying the flora from images that predominantly show an insect proved difficult for both experts and the Pl@ntNet app. The workflow performs with a 75% probability of correct identification of the plant at the species level from a score of 0.8, and with over 90% chance of correct family and genus identification from a score of 0.5. Although the number of images above these scores may be limited due to the flower parts present on the pictures, our approach can help to get an overview into species interactions and generate more specific research questions. It could be used as a triaging method to select images for further investigation. Additionally, the manual analysis of the images has shown that the information they contain offers great potential for learning more about the ecology of an introduced species in its new range. [ABSTRACT FROM AUTHOR]

Bees are important pollinators and are essential for the reproduction of many plants in natural and agricultural ecosystems. However, bees can have adverse ecological effects when introduced to areas outside of their native geographic ranges. Dozens of non-native bee species are currently found in North America and have raised concerns about their potential role in the decline of native bee populations. Osmia taurus Smith (Hymenoptera: Megachilidae) is a mason bee native to eastern Asia that was first reported in the United States in 2002. Since then, this species has rapidly expanded throughout the eastern part of North America. Here, we present a comprehensive review of the natural history of O. taurus , document its recent history of spread through the United States and Canada, and discuss the evidence suggesting its potential for invasiveness. In addition, we compare the biology and history of colonization of O. taurus to O. cornifrons (Radoszkowski), another non-native mason bee species now widespread in North America. We highlight gaps of knowledge and future research directions to better characterize the role of O. taurus in the decline of native Osmia spp. Panzer and the facilitation of invasive plant-pollinator mutualisms. [ABSTRACT FROM AUTHOR]

The solitary bee Osmia lignaria is a native pollinator in North America with growing economic importance. The life cycle of O. lignaria provides a unique opportunity to compare the physiological and molecular mechanisms underlying two ecologically contrasting dormancies within the same species. O. lignaria prepupae become dormant during the summer to avoid high temperatures. Shortly after adult eclosion, they enter a second dormancy and overwinter as diapausing adults. To compare these two dormancies, we measured metabolic rates and gene expression across development as bees initiate, maintain, and terminate both prepupal (summer) and adult (overwintering) dormancies. We observed a moderate temperature-independent decrease in gas exchange during both the prepupal dormancy after cocoon spinning (45 %) and during adult diapause after eclosion (60 %). We sequenced and assembled a high-quality reference genome from a single haploid male bee with a contiguous n50 of 5.5 Mbp to facilitate our transcriptomic analysis. The transcriptomes of dormant prepupae and diapausing adults clustered into distinct groups more closely associated with life stage than dormancy status. Membrane transport, membrane-bound cellular components, oxidoreductase activity, glutathione metabolism, and transcription factor activity increased during adult diapause, relative to prepupal dormancy. Further, the transcriptomes of adults in diapause clustered into two groups, supporting multiple phases of diapause during winter. Late adult diapause was associated with gene expression profiles supporting increased insulin/IGF, juvenile hormone, and ecdysone signaling. [Display omitted] • Prepupal dormancy and adult diapause are characterized by moderate metabolic suppression. • We assembled a high-quality reference genome with an n50 of 5.5 Mbp • Transcriptomes cluster by life stage, not dormancy status. • Adult diapause has two distinct gene expression profiles, indicating multiple phases. [ABSTRACT FROM AUTHOR]

A functional ecological understanding of urban wild bee communities is of growing importance especially in regard to biodiversity conservation, ecosystem service maintenance and effective conservation programmes. In this paper, we review and summarize the published literature aiming to inform future research investigations in the growing field of wild bee functional ecology. Specifically, we: (1) review which functional trait-based analyses have been carried out on wild bees in cities thus far; (2) summarize which wild bee species traits have been considered; (3) evaluate any consistent wild bee trait–environment relationships (i.e. urbanization) across studies; and (4) synthesize findings and limitations to inform future research recommendations. We reviewed 48 studies based on a systematic Web of Knowledge search. We found consistent trait characteristics for 'nesting type', 'diet', 'body size', 'sociality' and 'phenology' across studies. More than one third of the studies were descriptive and the majority of studies were located in urban gardens in temperate Europe and North America, calling for more research from underrepresented geographic regions and from the entire spectrum of urban habitat types. Of these studies, only five analyzed functional diversity indices and three studies applied statistics to relate urban wild bee traits to urbanization factors. Future studies should consider trait-based statistics, and could incorporate functional trait-based ecological networks to examine network shifts across urbanization gradients. Our review suggests that we lack generalizable information about wild bee trait and urbanization relationships yet, making conservation recommendations challenging. Therefore, we propose more research that considers methodological recommendations to develop a comparable and comprehensive understanding of how urbanization affects the functional ecology of urban wild bees to link with specific urban conservation measures. [ABSTRACT FROM AUTHOR]

The rusty patched bumble bee, Bombus affinis, is an important pollinator in North America and a federally listed endangered species. Due to habitat loss and large declines in population size, B. affinis is facing imminent extinction unless human intervention and recovery efforts are implemented. To better understand B. affinis biology and population genetic and genomic landscapes, we sequenced and assembled the B. affinis genome from a single haploid male. Whole genome HiFi sequencing on PacBio coupled with HiC sequencing resulted in a complete and highly contiguous contig assembly that was scaffolded into a chromosomal context, resolving 18 chromosomes distributed across the 365.1 Mb assembly. All material for both HiFi and HiC sequencing was derived from a single abdominal tissue segment from the single male. These assembly results, coupled with the minimal amount of tissue destructively sampled, demonstrate methods for generating contiguous and complete genomic resources for a rare and endangered species with limited material available and highlight the importance of sample preservation. Precise methods and applications of these methods are presented for potential applications in other species with similar limitations in specimen availability and curation considerations., Competing Interests: Conflicts of interest The author(s) declare no conflict of interest., (Published by Oxford University Press on behalf of The Genetics Society of America 2023.)

Animal pollination has been recognized as an essential ecosystem function that is potentially under various environmental stresses. We investigated the landscape effects of forest cover at multiple spatial scales on the sexual reproductive success of a common woodland herb in North America, Maianthemum canadense. This species is a self-incompatible species and pollinated by insects requiring natural landscapes. Nine populations were selected in deciduous forests within agricultural fields of southern Ontano, Canada. We investigated whether fruiting success decreases as forest cover surrounding the plant populations increases at the landscape scale. Forest cover was quantified by the proportion of forest within six different radii from 250 to 1500 rn. Analyses showed relationships with the proportion of forest at 750and 1000-rn radii and fruiting success in populations of M. canadense. These findings suggest potential local extirpation of M. canadense and indicate that forest loss can negatively impact on even some common woodland herbs. [ABSTRACT FROM AUTHOR]

Forest-associated species, which depend on forest habitat for their survival, are among the world's most vulnerable species due to widespread forest loss. However, in many parts of the world, forests are re-growing. Thus, if forest-associated species can persist in young forests their conservation outlook is less bleak. We examined the effects of forest loss and regrowth on bee pollinators in eastern North America using three datasets totaling 36,605 individual specimens. First, we conducted a regional-scale study to identify forest-associated and habitat generalist bee species. Second, we examined how the abundance and richness of each group change with forest area and age, by collecting bees from forests chosen to vary orthogonally in these variables. Lastly, we examined whether the results of our field studies were consistent with long-term, regional trends in the richness of both groups, using a dataset of museum specimens collected between 1872 and 2011, which was a period of reforestation in our study region. We found that the abundance and richness of forest-associated bees increase with forest area, while being relatively insensitive to forest age. By contrast, habitat generalist bees are unaffected by forest area, but decrease in abundance with forest age. Consistent with these results, we found a 16% increase in the richness of forest-associated bees over a 140-year time series as reforestation occurred in eastern North America, but no significant trend for habitat generalists. Overall, our results show that the loss of forest area from a landscape harms forest-associated bees, and that young forests have high conservation value for both forest-associated and habitat generalist bees. [ABSTRACT FROM AUTHOR]

Urbanization is rapidly growing worldwide, yet we still do not fully understand how it affects many organisms. This may be especially true for wild bees that require specific nesting and floral resources and have been threatened by habitat loss. Our study explores the response of wild bee communities to an urbanization gradient in the Chicagoland region of Illinois. Specifically, we explored how both landscape scale impervious surface and local floral diversity across an urbanization gradient influenced 1) the composition of local bee communities, 2) the richness of native and non-native bees, and 3) the composition of bee functional traits. Over the course of our study, we documented 2,331 bees belonging to 83 different species, 13 of which were not native to North America. We found that impervious surface influenced the overall composition of bee communities. In particular, highly urban areas were composed of more non-native bee species and fewer native bee species. Additionally, bee richness and native bee richness responded positively to floral resources. Bee functional trait responses were variable, with floral diverse sites supporting greater richness of ground nesting, eusocial, and generalist bees regardless of landscape-level impervious surface. Importantly, our study provides evidence that urban areas can support diverse bee communities, but urban and suburban bee communities do differ in composition. Thus, bee conservation efforts in urban areas should focus on creating floral diverse habitats to help support more bee species, specifically native bee species, while also considering which bees are best supported by these conservation efforts., (© The Author(s) 2021. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Emergent fungal diseases are critical factors in global biodiversity declines. The fungal pathogenNosema bombiwas recently found to be widespread in declining species of North American bumble bees (Bombus), with circumstantial evidence suggesting an exotic introduction from Europe. This interpretation has been hampered by a lack of knowledge of global genetic variation, geographic origin, and changing prevalence patterns ofN. bombiin declining North American populations. Thus, the temporal and spatial emergence ofN. bombiand its potential role in bumble bee decline remain speculative. We analyzeNosemaprevalence and genetic variation in the United States and Europe from 1980, before an alleged introduction in the early 1990s, to 2011, extractingNosemaDNA fromBombusnatural history collection specimens from across this time period.Nosema bombiprevalence increased significantly from low detectable frequency in the 1980s to significantly higher frequency in the mid- to late-1990s, corresponding to a period of reported massive infectious outbreak ofN. bombiin commercial bumble bee rearing stocks in North America. Despite the increased frequency, we find no conclusive evidence of an exoticN. bombiorigin based on genetic analysis of globalNosemapopulations; the widespreadNosemastrain found currently in declining United States bumble bees was present in the United States before commercial colony trade. Notably, the USN. bombiis not detectably different from that found predominantly throughout Western Europe, with both regions characterized by low genetic diversity compared with high levels of diversity found in Asia, where commercial bee breeding activities are low or nonexistent.