Our social standards harshly criticize the promiscuous behavior, especially in females, but for honeybees it seems very healthy. Queen honeybees who engage in sexual orgies with many drones produce more disease-resistant colonies than monogamous ones.

Bee keepers were puzzled by this royal behavior, as seeking out for multiple mates spends more time and energy and puts the queens at greater danger for predators. "Even though just one male provides all the sperm that a queen needs for the rest of her life, queen honeybees go out on mating flights and obtain sperm from a dozen or more males," said lead author Thomas Seeley, Cornell professor of biology and chair of the Department of Neurobiology and Behavior.

Seeley and David Tarpy of North Carolina State University tested the most accepted hypothesis that queens' promiscuity increases colony disease resistance by rising the genetic diversity of their offspring, the worker bees. "This required a particularly nasty experiment, in which we inoculated colonies with the most virulent disease of honeybees that is known, the dreaded American foulbrood disease," said Seeley.

The honeybee queens were inseminated with sperm from either a single drone (in 25 colonies) or from 10 drones (in 24 colonies).

The brood colonies were infected with water tainted with spores of the highly virulent bacterium that infects bee larvae and causes the disease American Foulbrood.

The more genetically diverse colonies derived from females fecundated with "10 drones sperm" were significantly less affected by the disease several months later.

The findings are important for bee keeping, an industry that brings revenues of about $20 billion annually in the United States for pollinating services. "Beekeepers could boost the health of their colonies, say the researchers, by promoting the queens' promiscuity by providing plentiful drones where queens are mating."