Drone Questions

Swiss reader, Alexandra, writes a number of pertinent questions about drone bees and their role in honey bee reproduction. She asks, “How does a queen find drones for mating? Will they hang out near her hive until she comes out on her mating flight? Is the mating going on while in the air? Are these drones from various hives, or just from one? Does any mating occur with her own drones, who genetically would be her own children? Do drones die after mating? What are the drones doing all day before it’s time for mating flights? Why are drone eggs infertile? Why do workers need to be fertile? And, lastly, what happens if the bees have to stay home a few days, like in stormy weather?”

I’ll try to answer: Drones from many hives fly to spaces called drone concentration areas, DCAs, where they mate with queen bees in flight. Young queen bees fly to DCAs, usually more distant than ones occupied by drones from her own hive, making it unlikely for queens to mate with genetically similar hive mates. This helps prevent inbreeding, which results in inferior offspring. In the DCAs, drones seek flying queens by sight and pheromones. Drones die in the act of mating; usually more than a dozen mate with a queen. Alexandra questions the drones’ activity outside of their mating flights. Drones conduct no work; they eat honey and rest inside the hive. Workers and queens develop from fertile eggs, and drones develop from infertile eggs in a scheme, common among stinging insects, known as parthenogenesis. When queens make their mating flights, over a day or two, they collect a life-time’s supply of sperm from drones. The queens then self-fertilize each egg that they lay that is to become a worker or queen. If the queen lays an egg without fertilizing, it becomes a drone. Inclement weather can delay mating flights. Long delays result in sterile queens, like the drone-layer shown in today’s photo.

--Richard

Martins and Drones

The purple martin is the largest member of the swallow family. These strong flying, insect-eating birds migrate to North America in the spring, and return to South America in the summer. Martins nest in gourds hanging from vines in treetops or in man-made bird houses mounted on poles. During the spring and early summer, martins rear their young. They catch great numbers of flying insects to feed their rapidly growing offspring, and the martins are feeding young birds at the same time that honey bee colonies are at the height of queen bee production. Soaring high in the sky and performing aerial acrobatics, the martins grab flying insects at will. As martins climb, dive, and sweep through honey bee drone concentration areas 20 to 80 feet in the air, they likely catch some queen bees making mating flights as well as drones.

Peace Bee Farm employs drone-breeder colonies with added drone brood frames to increase the number of drones in the drone concentration areas with valued traits. This technique, called drone saturation, is intended to lessen queen matings with feral drones. While some healthy bees are lost to martin predation, I feel like the birds actually help by eliminating weak or slow flying queens and drones. Martins surely apply selective pressure on queen bees while the queens are vulnerable outside the hive. It is evident that martins fly through drone concentration areas, because numbers of drones follow the martins back to their nest. Drones have large eyes to see queen bees making their mating flights. They seem to be attracted to the martins that fly through their drone concentration area. Following a fast moving martin, a plume of drones has no trouble keeping up with the bird as it sweeps through the sky. The drones follow the martins all the way back to their nest. Today’s photo shows a drone in close pursuit of a martin. The birds seem to pay no attention to their “comet tail” of drones.

--Richard