Once the new workers begin to forage, the queen stops foraging and stays in the nest to produce more brood. The workers feed and care for the developing brood. Towards the end of summer the colony begins to produce reproductive queens and drones. When these reproductives mature, they leave the colony and mate. The new queens then find a suitable overwintering site and go into diapause over the winter.
Bumble bees form their colonies in existing cavities.
Depending on the species, they may inhabit abandoned rodent nests or cavities in logs. There are about 30 species in North America, and at least two have been domesticated for use in agriculture. New technological developments have made colonies available on a year-round basis. In western North America, Bombus occidentalis is the native bee that is available as a pollinator. In the east, Bombus impatiens is available as a pollinator.