Given widespread declines in pollinator communities and increasing global reliance on pollinator-dependent crops, there is an acute need to develop a mechanistic understanding of native pollinator population and foraging biology. Using a population genetics approach, we determine the impact of habitat and floral resource distributions on nesting and foraging patterns of a critical native pollinator, Bombus vosnesenskii . Our findings demonstrate that native bee foraging is far more plastic and extensive than previously believed and does not follow a simple optimal foraging strategy. Rather, bumble bees forage further in pursuit of species-rich floral patches and in landscapes where patch-to-patch variation in floral resources is less, regardless of habitat composition. Thus, our results reveal extreme foraging plasticity and demonstrate that floral diversity, not density, drives bee foraging distance. Furthermore, we find a negative impact of paved habitat and a positive impact of natural woodland on bumble bee nesting densities. Overall, this study reveals that natural and human-altered landscapes can be managed for increased native bee nesting and extended foraging, dually enhancing biodiversity and the spatial extent of pollination services.

While an increasing number of studies indicate that the range, diversity and abundance of many wild pollinators has declined, the global area of pollinator-dependent crops has significantly increased over the last few decades. Crop pollination studies to date have mainly focused on either identifying different guilds pollinating various crops, or on factors driving spatial changes and turnover observed in these communities. The mechanisms driving temporal stability for ecosystem functioning and services, however, remain poorly understood. Our study quantifies temporal variability observed in crop pollinators in 21 different crops across multiple years at a global scale. Using data from 43 studies from six continents, we show that (i) higher pollinator diversity confers greater inter-annual stability in pollinator communities, (ii) temporal variation observed in pollinator abundance is primarily driven by the three-most dominant species, and (iii) crops in tropical regions demonstrate higher inter-annual variability in pollinator species richness than crops in temperate regions. We highlight the importance of recognizing wild pollinator diversity in agricultural landscapes to stabilize pollinator persistence across years to protect both biodiversity and crop pollination services. Short-term agricultural management practices aimed at dominant species for stabilizing pollination services need to be considered alongside longer term conservation goals focussed on maintaining and facilitating biodiversity to confer ecological stability.

Many insects sequester nutrients during developmentally programmed periods, which they metabolize during subsequent life history stages. During these periods, failure to store adequate nutrients can have persistent effects on fitness. Here, we examined a critical but under-studied nutrient storage period in queen bumble bees: the first days of adult life, which are followed by a diapause period typically coinciding with winter. We experimentally manipulated availability of pollen (the primary dietary source of lipids and protein) and the sugar concentration of artificial nectar (the primary source of carbohydrates) for laboratory-reared queens during this period and examined three nutritional phenomena: (i) diet impacts on nutritional status, (ii) the timescale upon which nutrient sequestration occurs and (iii) the fitness consequences of nutrient sequestration, specifically related to survival across the life cycle. We found evidence that pollen and nectar starvation negatively impact lipid storage, whereas nectar sugar concentration impacts stored carbohydrates. The majority of nutrients were stored during the first ~ 3 days of adult life. Nutrients derived from pollen during this period appear to be more critical for surviving earlier life stages, whereas nutrients sequestered from nectar become more important for surviving the diapause and post-diapause periods. Negative impacts of a poor diet during early life persisted in our experiment, even when pollen and a relatively high (50%) nectar sugar concentration were provided post-diapause. Based on these findings, we posit that the nutritional environment during the early adult life of queens has both immediate and persistent impacts on fitness. These findings underscore the importance of examining effects of stage-specific nutritional limitations on physiology and life history traits in this social insect group. Moreover, the findings may shed light on how declining food resources are contributing to the decline of wild bumble bee populations.