Drone adult bodies are robust, their abdomenabdomen:
the segmented, posterior (third) part of the bee body that contains heart, honey, stomach, intestines, Malphigian tubules, reproductive organs, and sting
is rounded rather than tapered, and they have large eyes that meet at the top of their head. They have one additional antennal segment compared to workers.
Colonies rear the male drones only during favorable resource conditions. Their development takes three days longer than worker development. The mated queen places the unfertilized eggs that yield the drone in the larger horizontal drone cells. Drone rearing starts early in the spring expansion stage and is one of the signs that colonies may move into reproduction of the colony itself, known as swarming behavior. Following the summer solistice most colonies halt drone rearing, although the adult drones will still be found in colonies.
Adult drones are often found at the edges of the active brood rearing area. They do not contribute to the work of the hive. Drones can feed themselves, but they prefer to beg food and grooming care from workers. Drones must mature for one to two weeks before they begin to leave the hive. After orientation flights, they fly in afternoon hours for mating. They fly to a close-by Drone Congregation area (DCA), where drones from many hives gather together and drones form into comets, flying together in a well-defined area, chasing any virgin queens they encounter. They return to the hive to refuel after several minutes of comet flight, then return to mating flights. Successful drones die in the process of mating.
In the fall, workers slaughter adult drones. Shorter daylength and diminishing resources are the apparent stimulus. Workers force the adult drones out of the hive, and do not allow them to return. Scavengers like yellowjackets and flies usually feed on the dead and dying expelled drone bodies. In queenless colonies or areas where resources continue and there is less of a change in daylength, colonies may not kick out drones, although they may not rear many either.
The eyes of drone pupae, like those of workers and queens, change color from white to dark black as they age. The approximate pupal age can be estimated by eye color when cappings are removed. Since drones have but a single set of genes (from their mother and none from their father), recessive gene mutations show up more frequently in adult drones. One such mutation is white eyes in the adult (variously described as ivory, yellow, or chartreuse). White-eyed drones may have one or both eyes lacking color. (Worker bees may also have white eyes as adults due to a recessive gene characteristic.) Other mutations seen in drones are gynandromorphs (a mixture of male and female characteristics) or one-eyed drones (Cyclops). The white-eyed drone adults, cyclops or gynandromorph adults apparently live normally inside the colony but are not able to mate.
Koeniger G, Koeniger N, Ellis J, and Connor L. 2015. Mating Biology of Honey Bees. Wicwas Press, Kalamazoo, MI, US.
