Other Common Names
Western Yellow-banded Bumble Bee
Synonyms and other taxonomic changes
Often treated as a subspecies of its northern and eastern replacement B. terricola, but occidentalis may itself prove to be a species complex with cryptic diversity
Explanation of Names
Refers to its western distribution
Identification
White tail tip distinctive. Usually but not always with yellow band centered on T3 but this can be lacking or yellow of the metasoma may extend to other terga.
Range
southern Alaska [update: now recognized as a distinct species B. mckayi. See https://www.tandfonline.com/doi/full/10.1080/00222933.2021.1900444], western Canada [but far NW pertains now to B. mckayi], and western USA
Food
The Hosts section of its
Discover Life species page lists known associations based on specimen records and images.
Remarks
Has declined in the Pacific states including California. In the San Francisco Bay Area common until the early 1990s but now absent. Still regularly found in Colorado and elsewhere in the Rocky Mountains and has reappeared recently in small numbers at various sites in the Pacific Northwest.
Sympatric with another member of its subgenus, B. franklini of southern Oregon and adjacent northern California, which has not been seen since 2006 and is feared extinct.
Internet References
https://www.tandfonline.com/doi/full/10.1080/00222933.2021.1900444
