Effects of Genetic Diversity on thermoregulation in Apis mellifera.
- Honeybee queens mate with a large number of males. In our experiment, our honeybee queens mated with between 20-37 males. The evolution of hyperpolyandry in honeybees (Apis mellifera) is an interesting phenomenon, given that it will reduce the average relatedness amongst workers and potentially decrease the fitness benefits derived from cooperation. Past studies have suggested that mating with up ... read moreto 10 males can be explained as a mechanism to decrease the production of genetic misfits (i.e. diploid males). The benefits of polyandry beyond 10 matings are poorly understood, although recent studies have shown some fitness benefits of hyperpolyandry on disease resistance, behavioral traits, and colonial thermoregulation. We were interested in the benefits of genetic diversity on colony thermoregulation. We examined the relationship between thermoregulation and genetic diversity quantified as the patriline number of the colonies. We predicted that stability of thermoregulation, measured as temperature variance in the brood comb would correlate positively with patriline number. In addition, we explored the mechanism for the pathogenesis of behavioral fever in response to Ascosphaera apis infection. Based on previous experiments, we predicted that our experimental hives would increase brood comb temperature in response to A. apis spores. Our data suggest that increasing genetic diversity is not a predictor of thermoregulatory stability. Although genetic diversity may have fitness benefits in hive development, stability of thermoregulation does not seem to be influenced by genetic diversity in naturally foraging, naturally mated colonies. Our results revealed that specific temperature conditions are relevant to the pathogenesis of behavioral fever against A. apis in honeybee colonies. During the experiment, our experimental colonies failed to mount a behavioral fever when they were exposed to A. apis spores at an ambient temperature of ~33oC, which is above the germination temperature of A. apis. This result suggests that there is a temperature requirement in the generation of group fever in honeybee. Surprisingly, our results also showed a food-influenced temperature circadian rhythm in honeybees. When the colonies were given a sugar feed, hive temperatures were no longer correlated with ambient temperature, and comparison between the no-feed and feed periods showed a different thermoregulatory pattern. Although using food as an external cue for circadian patterns had been observed in organisms such as mice, a "food-related clock" in a superorganism has never been seen until now.read less