Bombus appositus

{{Short description|Species of bee}}

{{Speciesbox

| image = Bombus appositus lateral2.jpg

| status = LC

| status_system = IUCN3.1

| status_ref =

| genus = Bombus

| parent = Bombus (Subterraneobombus)

| species = appositus

| authority = Cresson, 1878

}}

Bombus appositus is a species of bumblebee known commonly as the white-shouldered bumblebee.Hatfield, R., et al. 2015. [http://www.iucnredlist.org/details/44938356/0 Bombus appositus.] The IUCN Red List of Threatened Species. Downloaded on 04 March 2016.NatureServe. 2015. [http://explorer.natureserve.org/servlet/NatureServe?searchName=Bombus+appositus Bombus appositus.] NatureServe Explorer Version 7.1. Accessed 4 March 2016. It is native to western North America, 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, thistles, gentians, owl's clovers, locoweeds, penstemons, and clovers. It especially favors subalpine larkspur (Delphinium barbeyi) and it serves as one of the plant's main pollinators.Manson, J. S., et al. (2013). [http://onlinelibrary.wiley.com/doi/10.1111/1365-2745.12144/full Dose-dependent effects of nectar alkaloids in a montane plant–pollinator community.] Journal of Ecology, 101(6), 1604-1612.

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, a species of cuckoo bumblebee.