Bumblebees have a fat furry look, and are large-bodied bees. Native to North America, bumblebees are a social bee that lives in colonies. At its peak in late summer a colony will usually have about 150-200 bees. There are about 250 species of bumblebees, which live primarily in temperate regions, and about two dozen species reside in Canada.
These large bees nest underground, in places like abandoned mice nests, and are affected by rain and poor soil drainage. A typical underground nest will be 15-23 cm in diameter with a tunnel 30 cm, sloping, and 2.5 cm wide.
Males and queens are born at the end of the season. Bumblebee queens, the only females to mate, do so in late summer and feed heavily to store fat. The bumblebee queen is the only colony member that over-winters. In the spring the queen lays her eggs in the nest and forages nectar and pollen to feed the larvae. When the first worker bees mature they take over the job of feeding the larvae. Males, produced from unfertilized eggs, mate and leave the nest to forage on their own. Bumblebees require sustenance throughout the spring, summer and fall.
The North American bumblebee species have a wide range of forage preferences and visit a wide variety of flowers for nectar. There are varying tongue-lengths among the bees and this makes them seek flower types with different shapes and corolla tube lengths. Short-tongued bumblebees will bite holes in the flower, and directly rob the flower of its nectar. Longer-tongued bumblebees are important pollinators of many legumes such as field beans and red clover.
Bumblebees are effective pollinators, but are not used to pollinate large cultivated areas because they are usually too small in number. Managed bumblebees are better pollinators of greenhouse produce, such as tomatoes.