Yellow-faced Bumble Bee

The Yellow-faced Bumble Bee (Bombus vosnesenskii) is a social bee in the family Apidae, found in the San Francisco Bay Area.

This species is one of three members of the Bombus species commonly found at garden sites throughout California. Bombus californicus (California bumble bee) and Bombus melanopygus (Black-tailed bumble bee) are also common.

Bumble bees have annual colonies and are present most of the flowering season. Similar to honey bees, bumble bee hives organize themselves in three castes: workers, drones and queens. Unlike honey bees, bumble bees of all three castes can be found foraging at flowers. Queens emerge early in the season, as early as January for some species. Workers are common from spring until fall, and new queens and males are produced at the end of the colony season.

Yellow-faced bumble bees are social bees that nest underground in abandoned rodent burrows. They may also nest in tufts of grass at ground level, or occasionally in abandoned bird nests in cavities.