The species is a social parasite of Bombus jonellus. In the Pyrenees, it will also parasitize Bombus pyrenaeus and Bombus monticola (Løken, 1984; Rasmont, 1988). Pittioni (1942) also proposed Bombus cingulatus as a possible host, a citation repeated by Celary, Fijal and Kosior (2003)