The removal of corpses of individuals that die within a social insect colony is called necrophoresis. Although most bees die in the field while foraging, a normal colony will lose about 100 bees a day inside the nest. Since these bees may have borne diseases, their corpses pose a threat to the continued health of the colony.
The “undertaker” bees comprise about one or two percent of the bees in a colony at any one time, and no more than about ten percent of the bees in a colony will serve as undertakers at any point in their lives. Like all labor in bee colonies, necrophoric behavior is performed by bees of a certain age, in this case about two weeks after emergence.
Undertaker bees apparently recognize dead bees by chemical odors that develop in the corpse shortly after death. The corpse is carried away from the colony in the mandibles of an undertaker bee (sometimes more than one), to a distance usually between five and 100 yards; it is then dropped. Such corpses disappear rapidly, probably eaten by scavenging insects such as ants.
When the colony is less active during cold and rainy weather, corpses are removed more slowly; in winter they may accumulate in large numbers inside the colony, and are removed in the spring.