Drone-worker heritability of oxidative stress resistance in honey bees (Apis mellifera)

Honey bees are currently facing numerous challenges that are detrimental to colony fitness.  Exposure to stress factors associated with their environment and management practices likely contribute to their susceptibility to challenges such as disease or nutritional stress.  The ability to resist or tolerate the effects of such stressors potentially varies among different colonies, which may be in part a function of genetic effects.  Here, we used an injection of paraquat, a synthetic herbicide and known inducer of oxidative stress in honey bees, to test the following.  First, we investigated if there was natural variation in stress resistance or tolerance levels among different patrlines.  We examined this by injecting drones with paraquat and tracking their mortality rate compared to controls.  Second, we determined the heritability of this drone resistance or tolerance to stress to worker offspring.  We achieved this by selecting high- and low-resistance drones, instrumentally inseminating queens with semen from each drone type, and quantifying the resistance/tolerance levels of resulting worker offspring.  Our findings will help commercial beekeepers breed for colonies that can withstand negative environmental or management effects using active selection for high stress-resistant drone lines.