In the United States there are about 40 species of bumble bees (Bombus), most native to North America. Bumble bees are generalist foragers, feeding on a diverse suite of pollen and nectar sources. Although bumble bees do not produce commercial quantities of honey, they arguably are very important in the pollination of native flowers in natural ecosystems. Occasionally bumble bees are used in commercial pollination, for example, in tomato greenhouses.
Bumble bees are generally furrier and have other physiological adaptations that allow them to fly in cold and cloudy conditions when other bees are inactive. This ability to survive in cold climates makes bumble bees important pollinators of alpine flowers in high elevations.
Social insects, bumble bees live and work in colonies headed by a single queen that is the “mother” of all the nest residents. Bumble bees are corbiculate, that is they have pollen baskets on their hind legs.
Although the specifics may vary, the general life cycle of bumble bees is:
*Solitary queens overwinter under the ground in small cavities (hibernaculae) which they excavate.
*As the soil begins to warm in the spring the queen emerges, flies, looks for a nest site (abandoned underground rodent holes, holes in building foundations, crevices in firewood stacks and similar locations), and feeds.
*Once a nest site is found, the queen bumble bee builds a small wax cup (honey pot) and collects pollen in the cup to feed her brood.
*After enough pollen is accumulated the queen bumble bee lays her eggs on the pollen and incubates the eggs by placing her abdomen over them.
*Approximately four weeks later the first workers emerge. These workers forage, care for the nest and care for successive broods.
*Throughout the summer the colony grows.
*Late in the season the queen, with the help of the workers, produces a clutch of male bumble bees followed by clutch of new queen bees.
*The new reproductive bumble bees leave the nest and find mates.
*After mating the males die. The new female queens then dig hibernaculae and become dormant for the winter before beginning the cycle again in the spring.
Bumble bees are identified by their color characteristics and morphological characteristics such as proboscis length, cheek length and the relation of their ocelli to the supraorbital line. I am pretty much limited to color characteristics and range in my efforts.
With that in mind, I believe this specimen is a Vosnesensky bumble bee (Bombus vosnesenskii). Its face is yellow and the T4 segment is also yellow with the remainder of the body being black. It is also very common in its range – coastal Washington, Oregon and California east to the Sierra Cascade Crest. Vosnesensky bumble bee is present, but uncommon, in Nevada.
This bumble bee was photographed in early March on early blooming daffodils in our yard near Lookout CA (Modoc County). The weather was sunny days alternating with cold, snowy weather. Since it is so early in the season I believe this may be a queen that recently emerged from her underground hibernaculum.