Submitted to: Apidologie
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 25, 2014
Publication Date: September 25, 2014
Citation: Eckholm, B.J., Huang, M.H., Anderson, K.E., Mott, B.M., Hoffman, G.D. 2014. Honey bee (Apis mellifera) intracolonial genetic diversity influences worker nutritional status. Apidologie. DOI: 10.1007/s13592-014-0311-4. Interpretive Summary: Honey bee queens mate with many males (drones), and this causes a colony to have genetic diversity in the worker population. Colonies with greater genetic diversity collect more pollen than those with lower diversity and have higher growth rates. Whether greater genetic diversity also causes colonies to process food and distribute it to nestmates more efficiently than colonies with low diversity is not known. To answer this question, we created sets of colonies headed by queens instrumentally inseminated with sperm from either one (low diversity – SDI) or twenty drones (high diversity-MDI). We compared protein consumption, processing, and allocation among nestmates between the sets of colonies. We found that nurse bees in MDI colonies consumed more pollen, had greater digestion rates and invested more protein in larvae than nurse bees from SDI colonies. Pollen foragers from MDI colonies had significantly higher amounts of protein in their hemolymph than foragers from SDI colonies. Genetic diversity is correlated with increased foraging and pollen collection. Our results suggest that this correlation may be driven, in part, by the behaviors of the nurse bees that consume, process and distribute more protein to adults and larvae resulting in a greater demand for this nutritional resource.
Technical Abstract: Honey bee queens mate with multiple males - a reproductive strategy known as polyandry - that results in colonies comprised of high intracolonial genetic diversity among nestmates. Several studies have demonstrated the adaptive significance of polyandry for overall colony performance and colony growth. Colonies that are more genetically diverse collect more pollen than colonies with less diversity. However, the effects of intracolonial genetic diversity on the ability to process and allocate protein among nestmates are unknown. We created colonies headed by queens instrumentally inseminated with sperm from either one or twenty drones, then compared protein consumption, processing, and allocation among nestmates. We found that nurse bees from colonies with multiple drone inseminated (MDI) queens consumed more pollen, had lower midgut protease levels, and invested more protein in larvae than nurse bees from single drone inseminated (SDI) queens. Pollen foragers from MDI colonies had significantly higher hemolymph protein titers than foragers from SDI colonies. While intracolonial genetic diversity is correlated with increased foraging, our results suggest that this correlation may be driven, in part, by the elevated resource demands of nurse bees in genetically diverse colonies, which process and distribute protein in response to the social context within the hive.