Honey bee (Apis mellifera) intracolonial genetic diversity influences worker nutritional status

Abstract

Honey bee queens mate with multiple males resulting in high intracolonial genetic diversity among nestmates; a reproductive strategy known as extreme polyandry. Several studies have demonstrated the adaptive significance of extreme 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 worker nutritional status are unknown. We created colonies headed by queens instrumentally inseminated with sperm from either 1 or 20 drones, then compared protein consumption, digestion, and uptake among nestmates. We found that nurse bees from colonies with multiple-drone-inseminated (MDI) queens consumed more pollen, had lower amounts of midgut tissue protease, and invested more protein into larvae than nurse bees from single-drone-inseminated (SDI) queens. Pollen foragers from MDI colonies had significantly higher hemolymph protein concentration than pollen foragers from SDI colonies. Differences in hemolymph protein concentration between nurses and pollen foragers were significantly smaller among MDI colonies than among SDI colonies. While intracolonial genetic diversity is correlated with increased foraging, our results suggest that this relationship may be driven in part by the elevated resource demands of nurse bees in genetically diverse colonies that consume and distribute more protein in response to the social context within the hive.