New Records of the American Bumble Bee, Bombus pensylvanicus, in Michigan

We report recent detections of the American bumble bee, Bombus pensylvanicus (De Geer) (Hymenoptera: Apidae), in 16 counties of Michigan, USA. This bee species is currently listed as state endangered in Michigan. The current report provides an update on the distribution of B. pensylvanicus in Michigan from collections made between 2020 and 2024, including detections from at least 21 locations in the Lower Peninsula, expanding the known distribution in this state. These samples were from four pollinator survey projects with records from photographs and collections and two online participatory science programs where users uploaded photographs of this species while verified by experts. Here, we provide information regarding the timing, location, and host plant associations of the new records of B. pensylvanicus and give recommendations for research and education to support this state-endangered bee species.