Shalene Jha

Animal cognition and brain morphology can vary between individuals and across a lifetime as a function of social and ecological requirements. Bumblebees have distinct ecological pressures acting upon individuals at different times: young queens (gynes) and workers share similar challenges as they both forage as part of the colony, but only queens overwinter and start a colony the following season, switching to a reproductive stage. Here, we compared bumblebee (Bombus impatiens) visual learning and brain morphology across age-matched workers and gynes and older reproductive queens. We expected foraging-stage gynes to be better at visual learning than reproductive queens and visual regions to be reduced in the reproductive queens, in line with work in other social insects. However, we found that gynes and queens performed similarly, and both performed better than workers. We also found that reproductive queens had larger olfactory regions (antennal lobes) than gynes, while visual regions (medulla and lobula) did not differ, indicating a greater investment in olfactory regions in this later reproductive stage. Brain regions also scaled differently with body size for gynes and workers. Overall, our results provide behavioral and morphological evidence that social and ecological roles in a colony shape cognition and neural investment.

Internal parasites and pathogens have not been a focus of wild bee systematic data collection efforts to-date but are important to document because they have been strongly linked to bee declines. Here, we provide a standardized protocol for collecting fresh bee tissue samples for generating parasite and pathogen data. The protocol emphasizes appropriate handling and storage conditions and data standards. It can be embedded within bee health monitoring projects or used by individual data collection efforts that aim to generate parasite and pathogen data now and in the future. This protocol is part of a series developed in association with the U.S. National Native Bee Monitoring Network to standardize bee monitoring practices.

This protocol provides guidance on the appropriate collection of bee specimens or tissue samples for molecular analysis, with an emphasis on generating genetic and genomic data while ensuring tissue integrity. Specifically, the protocol focuses on tissue collection and storage methods, including relevant specimen metadata recording and reporting, but does not cover any downstream handling or analyses, which vary depending on the aims of a given project or study. This protocol is specifically designed for freshly collected, individual bee specimens intended for genetic, genomic, or other molecular analyses. While molecular approaches to bee monitoring are not the primary focus, we emphasize their promising role for future applications. This protocol is part of a series developed in association with the U.S. National Native Bee Monitoring Network to standardize bee monitoring practices.

Animal cognition and brain morphology can vary between individuals and across a lifetime as a function of social and ecological requirements. Bumblebees have distinct ecological pressures acting upon individuals at different times: young queens (gynes) and workers share similar challenges as they both forage as part of the colony, but only queens overwinter and start a colony the following season, switching to a reproductive stage. Here we compared bumblebee ( Bombus impatiens ) visual learning and brain morphology across age-matched workers and gynes and older reproductive queens. We expected foraging-stage gynes to be better at visual learning than reproductive queens and visual regions to be reduced in the reproductive queens, in line with work in other social insects. However, we found that gynes and queens performed similarly, while both performed better than workers. We also found that reproductive queens had larger olfactory regions (antennal lobes) than gynes, while visual regions (medulla and lobula) did not differ, indicating a greater investment in olfactory regions in this later reproductive stage. Brain regions also scaled differently with body size for gynes and workers. Overall, our results provide behavioral and morphological evidence that social and ecological roles in a colony shape cognition and neural investment.

Pollination is a key ecological process sustaining biodiversity and food security, yet global patterns of plant–pollinator specialisation have remained unresolved. Using the largest global dataset of quantitative networks (>3,400 networks, >110,000 interactions), we show that the latitudinal specialisation gradient (LSG) exists, but it is non-linear, hemispherically asymmetric, and strongly taxon-dependent. Network-level and pollinator specialisation were lowest in the tropics and peaked at northern mid-latitudes, whereas plants tended to become more specialised toward higher latitudes. Climate consistently outperformed latitude, species richness, and environmental productivity as a predictor of these patterns. Specialisation declined with increasing temperature, rose with moderate rainfall before declining at the wettest sites, and increased with temperature seasonality, but plants and pollinators responded differently to these drivers. Functional groups diverged strongly: ectothermic insects were most specialised in cooler, seasonal climates, while birds showed weaker links to latitude but reduced specialisation in wetter regions. These findings demonstrate that climate, rather than latitude or species richness, structures global variation in specialisation. Because warmer and less seasonal climates promote generalisation, climate change is likely to disrupt the most specialised pollination systems, unevenly across taxa and regions, with important consequences for biodiversity and ecosystem stability.

Land use change threatens global biodiversity and compromises ecosystem functions, including pollination and food production. Reduced taxonomic α‐diversity is often reported under land use change, yet the impacts could be different at larger spatial scales (i.e., γ‐diversity), either due to reduced β‐diversity amplifying diversity loss or increased β‐diversity dampening diversity loss. Additionally, studies often focus on taxonomic diversity, while other important biodiversity components, including phylogenetic diversity, can exhibit differential responses. Here, we evaluated how agricultural and urban land use alters the taxonomic and phylogenetic α‐, β‐, and γ‐diversity of an important pollinator taxon—bees. Using a multicontinental dataset of 3117 bee assemblages from 157 studies, we found that taxonomic α‐diversity was reduced by 16%–18% in both agricultural and urban habitats relative to natural habitats. Phylogenetic α‐diversity was decreased by 11%–12% in agricultural and urban habitats. Compared with natural habitats, taxonomic and phylogenetic β‐diversity increased by 11% and 6% in urban habitats, respectively, but exhibited no systematic change in agricultural habitats. We detected a 22% decline in taxonomic γ‐diversity and a 17% decline in phylogenetic γ‐diversity in agricultural habitats, but γ‐diversity of urban habitats was not significantly different from natural habitats. These findings highlight the threat of agricultural expansions to large‐scale bee diversity due to systematic γ‐diversity decline. In addition, while both urbanization and agriculture lead to consistent declines in α‐diversity, their impacts on β‐ or γ‐diversity vary, highlighting the need to study the effects of land use change at multiple scales.

Urban community gardens are important social–ecological systems from which urban citizens receive many benefits. In this study of 18 urban community gardens in the Central Coast of California, USA, we use a combination of gardener surveys and field-based measurements to evaluate the amount of fresh fruit and vegetables produced by gardeners. We then investigate how food production differed between segments of the gardening population, specifically as a function of gardening experience, time spent in gardens, and food security status. Lastly, we ask gardeners to describe their motivations for gardening to better understand how motivations may relate to individual levels of food production. Thirty-eight percent of gardeners estimate harvesting one to five pounds of food per week, with another 26% estimating six to ten pounds. These estimates were corroborated by field measurements of tomato, squash, and pepper cultivation, where gardeners produced, at the height of the harvest season, an average of four pounds of food per week—an estimated savings of ~ $16USD per week (compared to the cost of local organic fruits and vegetables, June 2023 prices). Regarding the ability of community gardens to reduce food insecurity, gardeners who spent more time in the garden and with higher incomes reported higher food security, while those with larger families or lower incomes were more food insecure. These results show that gardeners in most need of food support were not necessarily the ones cultivating the most fruits and vegetables. While 48% of gardeners reported food cultivation as a primary motivator for gardening, many other motivations (e.g., hobby, being outdoors, relaxation, social interaction, and exercise) were identified as reasons to spend time in the garden, indicating that food production is not the only factor motivating gardeners. Overall, we document that community gardens can be highly productive and provide valuable produce that substantially offsets high fresh food costs; however, gardeners with the greatest food needs are currently not the largest producers, but could benefit from additional resources and support.

Predicting how habitat composition alters communities of mobile ecosystem service providers remains a major challenge in community ecology. This is partially because separate taxonomic groups that provide the same service may respond uniquely to changes in habitat and associated resource availability. Further, the spatial scale at which habitat features impact each group can vary. Failure to account for these differences significantly limits the ability to quantify shared versus contrasting responses to habitat for important ecosystem service-providing groups. We investigated the impacts of local (habitat patch level) and landscape features in the US Southern Great Plains on groups of pollinating insects with different basic biologies: Coleoptera, Diptera, Hymenoptera, and Lepidoptera. Habitat features included local flower and shelter resources as well as landscape-scale semi-natural habitat. We found that bare ground supported more Hymenoptera and Lepidoptera but fewer Diptera, while more diverse flower communities supported more Hymenoptera but fewer Coleoptera. Interestingly, given that this study occurred in a grassland system, forest cover in the surrounding landscape more strongly affected pollinator diversity than grassland cover did. Landscapes with more woodland had higher Coleoptera and Diptera richness. Our results highlight that pollinator conservation and sustainable land management depend on understanding the habitat needs, including shelter, of diverse pollinators. Because taxa can have opposite responses to specific habitat features or scales, providing a range of grassland management practices (e.g., variety in the timing and type of biomass removal) may be the most effective approach to support the broader pollinator community.