Drone Congregation Areas
By Tom Webster, PhD
Editor’s Note: Dr. Tom Webster spoke about the fascinating concept of Drone Congregation Areas (DCAs) at Kelley’s Field Day, on June 2, of 2012. He gave us permission to share the hand-out he provided, covering both fundamentals and amazing insights into this behavior.
Drones and queens fly to specific locations where they mate while flying. The drones that mate die soon afterward. The mated queens fly back to their hives.
The queens will mate with from 5 to 40 drones, during one or several mating flights. After their mating flights, the queens will develop large ovaries and not mate again. The semen from the mating is stored in the queen’s spermatheca, where it will last for years if the queen remains healthy. The spermatheca is a tiny organ about 1/2 millimeter across. The queen releases a few sperm to fertilize each egg as it passes down her reproductive tract, except for the eggs destined to become drones which develop from unfertilized eggs.
Why does a queen mate with so many drones? Genetic diversity within the colony helps it function more effectively.
How do drones and queens find these congregation areas? The bees choose the same places each year, even though there can be no “memory” of these spots. New drones and queens find them quite reliably. Some studies suggest that differences in the earth’s magnetic field lead bees to these places. Bees have magnetic tissue in their brains, like some other animals and people too.
Lines of trees or a ridge that ends abruptly may be an important indicator. There will be a cloud of drones circling about 50 ft above the ground. They will quickly chase any queen that passes into this area. Drones use their enormous eyes and also their ability to smell the queen’s pheromone.
The congregation areas may be close to hives or miles away. Drones fly farther than queens to reach congregation areas. This promotes out-breeding. Inbreeding is very unhealthy for honeybees. Drones from one hive may fly to different congregation areas in different directions from the hive.
Mating flights are usually late afternoon. Watch your hive entrances 4 p.m. - 6 p.m. during the April to June peak mating period.
Most drones are unsuccessful at mating. Perhaps 1 or 2% of drones are successful. Drones that survive until fall are evicted from their hives, usually after frosty nights in October.