D3192: Bee traits across grassland grazing regimes

Pollinators, including bees, are vital to grassland ecosystems. In North America, grazing is an important tool for managing grassland ecosystems. However, there is limited knowledge on how grazing influences pollinator habitat in grasslands. Trait-based approaches are a powerful research tool to investigate the relationship between grazers, pollinators, and their habitat. Research using bee traits can improve our understanding of bees’ ecology, including their dispersal dynamics and roles as pollinators. In this project, we measured bee body size and corbicular area, which are proxies for dispersal ability and pollen carrying capacity. In 2024, we collected bees from prairies in Kansas and Montana in sites under a range of grazing practices (KS: cattle, bison, ungrazed; MT: cattle, bison, ungrazed, prairie dog). We investigate 1) whether body size and corbicular area vary with floral resources and habitat characteristics, and 2) whether these traits vary with grazing management practices. We expect that bison- and cattle-grazed sites will have greater floral richness and abundance due to the selective grazing of these herbivores. We hypothesize that larger bees, which are able to disperse larger distances and carry more pollen, will be found in areas with greater floral resources, because they can travel to more florally abundant sites. Linking bee size to habitat characteristics and management practices is important for understanding the dispersal dynamics and function of bees in today’s fragmented grasslands.