''Bombus appositus'' is a species of

bumblebee A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only Extant taxon, extant group in the tribe Bombini, though a few extinct r ...

known commonly as the white-shouldered bumblebee.Hatfield, R., et al. 2015
''Bombus appositus''.
The IUCN Red List of Threatened Species. Downloaded on 04 March 2016.NatureServe. 2015
''Bombus appositus''.
NatureServe Explorer Version 7.1. Accessed 4 March 2016. It is native to western

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, including western Canada and the western United States. This species lives in open habitat, such as meadows and slopes. It nests underground or on the surface. Males congregate to seek mates. It feeds on a variety of plant taxa, including giant hyssops,

thistle Thistle is the common name of a group of flowering plants characterized by leaves with sharp spikes on the margins, mostly in the family Asteraceae. Prickles can also occur all over the planton the stem and on the flat parts of the leaves. T ...

s, gentians, owl's clovers, locoweeds,

penstemon ''Penstemon'' , the beardtongues, is a large genus of roughly 280 species of flowering plants native to North America from northern Canada to Central America. It is the largest genus of flowering plants endemic to North America. As well as bein ...

s, and

clover Clovers, also called trefoils, are plants of the genus ''Trifolium'' (), consisting of about 300 species of flowering plants in the legume family Fabaceae originating in Europe. The genus has a cosmopolitan distribution with the highest diversit ...

s. It especially favors subalpine larkspur (''Delphinium barbeyi'') and it serves as one of the plant's main pollinators. This species has a range from southwestern Canada south to the Cascade Mountains and the Sierra Nevada, and west to central Californiahttps://fieldguide.mt.gov/speciesDetail.aspx?elcode=IIHYM24040 This species is a host to ''

Bombus insularis ''Bombus insularis'' is a species of bumblebee in the subgenus ''Psithyrus'', the cuckoo bumblebees. It is native to northern and western North America, where it occurs throughout Canada, Alaska, the northern United States, and some western stat ...

'', a species of

cuckoo bumblebee Cuckoo bumblebees are members of the subgenus ''Psithyrus'' in the bumblebee genus ''Bombus''. Until the 1990s, ''Psithyrus'' was considered to constitute a separate genus.Williams, P.H. 1994. Phylogenetic relationships among bumblebees (''Bombu ...

References

Bumblebees Hymenoptera of North America Insects described in 1878 {{bombus-stub