Floral Visitation and Pollen Collection by Native Bees in Temperate Deciduous Forests with Diverse Understory Communities

Abstract The native bees associated with deciduous forest are likely the pre-colonial dominant bee fauna of the eastern United States, yet we lack the data on their resource use needed to guide management. We characterized bees’ floral resource use in mature deciduous forests managed by the National Park Service at sites spanning ~ 550 km of latitude in Indiana and Michigan. We collected floral visitation records for 4194 bee specimens representing 103 species, and data on bees’ pollen collection for 665 specimens. Our findings highlight differences among dominant bee genera in their floral resource use, especially pollen, and confirm the importance of canopy tree species and shrubs for bees in deciduous forests, even in those with diverse understory floral assemblages. As the largest, most spatially extensive source of data on bees’ use of floral resources within mature deciduous forests in North America, these records provide a useful reference point for forest bee conservation.