Genetic diversity affects colony survivorship in migratory beekeeping operations

Recent surveys suggest that an important problem in managed honey bee colonies are ‘poor queens’. Arguably the single most important attribute of a queen’s “quality” is how well she is mated. Queens mate with an average of approximately 12 drones, although there is significant variation among queens. Aside from supplying enough sperm for her egg-laying lifetime, one main consequence of polyandry is an increased diversity of the genotypes of workers within a colony. This increased intracolony genetic diversity has been shown empirically to confer significant adaptive advantages. In this study, we compare the mating frequencies of queens—and therefore the intracolony genetic diversity—in three commercial beekeeping operations to determine how they correlate with various measures of colony health and productivity, particularly the likelihood of queen supersedure and colony survival. We genotyped a total of 3,098 workers belonging to 79 colonies, and we found the average effective paternity frequency (me) to be 13.6 ± 0.76. The number of effective matings did not differ between colonies surviving verses not surviving the study. Similarly, effective mating frequency was not different between colonies that superseded their queen and those that did not. However, colonies headed with queens that had me ≤ 7.0 were 3.77-times more likely to die by the end of the study when compared to colonies headed by queens with me > 7.0. The stark contrast in colony survival based on increased genetic diversity suggests that there may be practical benefits of increased queen mating number in commercial honey bee colonies.