Bombus caliginosus (Obscure Bumble Bee)
Credit: Robin Gwen Agarwal
about the species
Bombus caliginosus (obscure bumble bee) is native to the Western Coast of the United States. Its distribution extends from Washington through Oregon to Southern California, as far south as the San Jacinto Mountains. This species is very similar to the yellow-faced bumble bee (B. vosnesenskii), and the two can be told apart genetically or using a few distinctive physical characteristics, including the length of their molar cheek, the structure of the male genitalia, yellow hairs found on the underside of the abdomen, and the irregular length on their hairs.
why species was selected
B. caliginosus is an ecologically important pollinator, and it is considered Vulnerable by the IUCN and is a Species of Special Concern in California. Analyses suggest very high population decline in relative abundance and range-wide. However, the level of population decline is difficult to ascertain due to its close resemblance to B. vosnesenskii, and more surveying is necessary.
