Pyrobombus
Guides
Bombus bifarius
Two-form bumblebee
Bombus bifarius is a eusocial bumble bee of the subgenus Pyrobombus, first described by Cresson in 1879. Recent genetic research (2020) has clarified its taxonomy: what was historically considered a single species with two color morphs (red-tailed 'bifarius' and black-tailed 'nearcticus') has been split into two cryptic species. True B. bifarius is now restricted to the red-tailed form found in the southern Rocky Mountains, while the black-tailed and variable forms belong to the sister species Bombus vancouverensis. The species is small-bodied and has been identified as one of only two bumble bee species known to use pheromones in kin recognition.
Bombus vancouverensis nearcticus
Nearctic Bumble Bee
Bombus vancouverensis nearcticus is a subspecies of bumble bee native to western North America. It belongs to a species complex that has undergone taxonomic revision, with some authorities previously treating it as a distinct species (Bombus nearcticus) or synonymizing it with related taxa. The subspecies occurs in montane and coastal regions where it participates in pollination networks. Like other bumble bees in the subgenus Pyrobombus, it exhibits social colony structure with a single queen founding nests in spring.