Wild Bees (Hymenoptera: Apoidea: Anthophila) of the Michigan Highbush Blueberry Agroecosystem

Abstract

Abstract Highbush blueberry (Vaccinium corymbosum L.) is a native North American crop dependent upon pollen movement by bees for high fruit set and large berries. Commercial blueberry farms use honey bees (Apis mellifera L.) to provide pollination services, but there is concern regarding their long-term sustainability as crop pollinators. We conducted a 3-yr study at 15 farms to identify the bee community associated with the blueberry agroecosystem in Michigan to improve our understanding of this community and to better target conservation practices. Pan trapping and direct observation were used to determine the relative abundance and diversity of wild bees before, during, and after bloom. We found at least 166 species, representing 30 genera and five families, 112 of which were active during bloom. Most bees captured were solitary, soil-nesting bees. Most species were from subfamily Halictinae (family Halictidae) and genus Andrena (family Andrenidae). Andrena Carolina Viereck, a specialist on Ericaceae, was the most abundant native bee species collected during blueberry bloom. Several native Osmia species that were present in low abundance during bloom are potential targets for management. Honey bees were more often captured in white than in yellow traps, regardless of trap position in the field. Wild bees were more often captured in field perimeters than interiors, but they did not respond differentially to trap color. We report seven new state records for Michigan, including significant range extensions, and three new floral record associations. Implications for the conservation of native bees in this agricultural system are discussed.