From Science:
When a new queen begins her reign over a colony of honeybees, she gives up her virginity with gusto. Venturing outside the hive and flying to a height of 6 meters or more, the queen mates in midair with a dozen or so male bees, called drones, who all die after ejaculating. The reason for this acrobatic orgy–polyandry is the polite term–has long been a puzzle.
Here’s the conundrum: When the queen buzzes back to the hive and lays eggs, she fertilizes them with sperm from the various drones she mated with. That means many of the female workers will be half-sisters, and these bees should be less likely than full sisters to work for each others’ benefit, at least according to the theory of kin selection. So why doesn’t the queen mate with a single male and keep the hive as one tight family?
According to a study in the 20 July issue of Science, a genetically diverse hive can be vastly more productive than a homogenous hive of sisters.
More here.