Bombus ashtoni

    In the U.S., the social parasite Bombus (Psithyrus) ashtoni is a northern boreal species that cooccurs with its hosts Bombus affinis and Bombus terricola. Records of the socially parasitic subgenus Psithyrus are rare, so it is possible that B. ashtoni may be found in South Dakota, northern Iowa, and far northern Illinois and Indiana.