Some bees are communal. They are like solitary bees except that several females of the same generation use the same nest, each making her own cells for housing her eggs, larvae, and pupae. A few kinds of bees are semisocial-they live in small colonies of two to seven bees of the same generation, one of which is the queen, or principal egg layer; the others are worker bees. About 1000 species of bees live in small colonies consisting of a queen and a few daughter workers. In these colonies, the differences in appearance and behavior between workers and queens are scarcely distinguishable. Such species, called primitively eusocial, form temporary colonies that die out in autumn, and only the fertilized queens survive the winter. Bumble bees are familiar examples.
The eusocial, or truly social, bees live in large colonies consisting of females of two overlapping generations: mothers (queens) and daughters (workers). Males play no part in the colony's organization and only mate with the queens. Larvae are fed progressively-that is, cells are opened as necessary or are left open so that workers can tend the larvae. Highly eusocial bees, a few hundred species, form permanent colonies in which the queen and worker castes are markedly different in structure, each specialized for its own activities and unable to survive without the other. Colonies of eusocial bees are complex, highly coordinated societies. Individual bees may have highly specialized functions within the colony. The tasks of defense, food collection and storage, reproduction, and many other activities are regulated by the colony's response to environmental conditions inside and outside the hive. Individuals communicate by means of chemical messages, touch, sound, and, in the case of honey bees, a symbolic dance language. The nests of many eusocial bees are very elaborate and may be constructed partially of wax secreted by the bees.
Parasitic, or cuckoo, bees are those that do not forage or make nests themselves but use the nests and food of other species of bees to provide for their parasitic young. Parasitic bees are of two types: cleptoparasitic bees and social parasites. Cleptoparasitic bees invade the nests of solitary bees, hide their eggs in the brood chambers before the hosts lay theirs, and close the chambers. The young of the parasitic bees then feed on the food that was stored in the chamber by the host female. The eggs or young larvae of the host bee are killed either by the parasitic female or by her larvae. Social parasites are bees that kill the resident queen, lay their own eggs in the host's cells, and then force the host's workers to raise the young parasitic bees. Females of parasitic bees lack such special features as pollen baskets or pollen brushes since they do not forage for food for their young.
There are 11 families of bees. Scientists distinguish between them by subtle differences in wing veins and by the fine structure of the mouthparts and other microscopic characteristics. However, the bees in each family have other interesting descriptive features, including their size, nesting and foraging behaviors, and easy-to-see body features such as body hair, the length of the tongue, and the form of the pollen-carrying structure.
Cellophane bees are relatively hairless bees with short, forked tongues. They resemble wasps more so than other bees; hence they are considered the most primitive bees. They line their nest tunnels and larval cells (chambers for the young) with a secretion that hardens into a cellophane-like membrane. They carry pollen on leg hairs or internally in a stomachlike crop. Mining bees are a large group of bees that make soil nests of many branching chambers, each ending in one or more cells. They are either solitary or communal, living in separate but nearby nests. They carry pollen on body and leg hairs.
Sweat bees are generally small, dark-colored bees with little hair. They, too, usually nest in the ground but may live in societies in which related individuals help each other. Pollen is carried on brushy areas near the base of the legs and on body hairs. Leafcutter bees and mason bees belong to a family of long-tongued bees that have specialized pollen-carrying hairs on the underside of the abdomen. They often make their nests in preexisting cavities and may live in groups of individual nests. Some are used in agriculture to pollinate crops. Digger bees are fast-flying, fuzzy bees that may nest in the ground solitarily or in dense clusters or may excavate nests in wood. They have long tongues and are excellent pollinators of many plants. They carry their pollen on brushy areas near the middle of the hind leg. Carpenter bees are also in the digger bee family.
The most familiar bees are the honey bees and their close relatives. In this family are bees that make intricate nests and live in complex societies. The pollen-carrying structure in these bees is a smooth, bristle-surrounded area on one segment of the hind leg. This structure is known as a pollen basket, or corbicula. This group is divided into four tribes: the orchid bees, the bumble bees, the stingless bees, and the honey bees.
Scientific classification: Bees make up a superfamily known as the Apoidea. Cellophane bees make up the family Colletidae, mining bees make up the family Andrenidae, sweat bees make up the family Halictidae, the leafcutter and mason bees and their relatives make up the family Megachilidae, the digger bees make up the family Anthophoridae, and honey bees and their relatives make up the family Apidae.
Contributed by: Charles D. Michener