The curious promiscuity of queen honeybees (Apis mellifera): Evolutionary and behavioral mechanisms

Even after considerable effort and debate, it remains unclear why honey bee queens frequently mate with 10 or more males. We address both why polyandry is adaptive to queens and how queens obtain such extreme numbers of mates. We review a manipulative experiment which tested the hypothesis that multiple mating reduces the genetic load caused by the honey bee sex determination system. Our results suggest that multiple mating (i.e, mating more than once) increases a queen's fitness by lowering the probability that she produces a high proportion of inviable, diploid males within her brood. Furthermore, we examined the relationship between a queen's mating behavior and her mating number. We propose that "extreme" polyandry in honey bees (i.e., mating numbers ≥10) may be inadvertent consequences of a queen's mating behavior, therefore additional adaptive arguments are not needed to explain why honey bees have some of the highest mating numbers among the social insects.