Bombidae

a family of large bumblebees that measure as much as 3.5 cm long and are densely covered with hair. The coloration is a combination of black, white, red-yellow, and yellow stripes. There are about 300 species, distributed mainly in temperate climates. The bees can tolerate northern climates; for example, their range includes Greenland, Novaia Zemlia, the Chukchi Peninsula, and Alaska. About 100 species occur in the USSR.

Social insects, the bees live in families consisting of three castes—males, reproductive females (queens), and nonreproductive females (workers). Families are formed in the spring, with only the fertilized queens surviving through the next winter. In the spring the queens build nests and form new families. The nests, which are usually spherical and contain irregular oval cells, are built in the abandoned burrows of rodents, in the ground, in the grass, or under roofs. The queen builds a brood cell from a mixture of wax and pollen and places a few eggs into it. She then builds a cell, or waxen pot, to store honey. The larvae are fed a combination of pollen and nectar in one common cell, a feature unique to the Bombidae. Prior to pupation, each larva builds its own cocoon. With the emergence of the workers from the cocoons, the queen no longer leaves the nest. The workers build new honeycombs and feed the brood, from which the reproductive males and females appear at the end of the summer. In the fall the young males and females leave the nest and mate. Soon thereafter the males die, and the young females find sheltered areas for hibernation. In old families that have survived until autumn, all the workers die by the time winter arrives. Families usually consist of 100 to 200 (rarely to 500) individuals.

The bees are the principal pollinators of valuable forage crops, including clover, alfalfa, and many other legumes. The nests are protected. Methods are being developed to resettle the bees artificially and to increase their numbers.