Other Common Names
Has been called the "Van Dyke" Bumble Bee, but use of the possessive should be preferred when forming such a name (see AOU and BOU bird checklists).
Synonyms and other taxonomic changes
Bremus vandykei Frison, 1927; Pyrobombus (Pyrobombus) cascadensis Milliron, 1970
Females resemble the sympatric and generally more numerous vosnesenskii, but in vandykei the yellow band is on T3 rather than T4. This character is often hard to observe in the field so this species is under-recorded in visual and photographic surveys. Males are extensively yellow, as in B. perplexus of northern and eastern North America, with a contrasting black tip to the metasoma and a variable amount of black hairs on the scutum. These have been confused with the much larger B. fervidus, but these are rarely sympatric and differ considerably in structure (note subgeneric characters).
Characteristic of relatively dry foothills of the Pacific Coastal States but also extends locally to higher mountains and lowlands.
Relatively dry shrubby habitat seems to be preferred.
The Hosts section of its Discover Life species page
lists known associations based on specimen records and images.
May be under-recorded in bumble bee surveys due to great similarity of females to the ubiquitous B. vosnesenskii and its preference for drier habitats than those preferred by many other bumble bee species (and by bumble bee specialists).
Thorp, R. W., D. S. Horning, Jr. and L. L. Dunning. 1983. Bumble Bees and Cuckoo Bumble Bees of California. Calif. Insect Survey, vol.23 (available as PDF