Genotypic diversity in queenless honey bee colonies reduces fitness

Abstract

SummaryHoney bee queens mate with many males. The resulting genotypic diversity appears to enhance fitness of queenright colonies (those colonies with a reproductive queen present) which is difficult to measure, because measures of long-term fitness include successful matings of produced male sexuals (drones) and number of surviving swarms. The fitness of queenless colonies is, however, limited to worker-produced adult drones until natural colony death. Here we test the impact of genotypic diversity on fitness of queenless honey bee colonies, which were headed by queens inseminated with one, 10 and 20 drones or naturally mated. The data show that genetically diverse queenless colonies (20 subfamilies per colony) produced fewer adult drones, had a delayed onset of worker-derived drone flight activity, and a lower efficacy in drone production/per day colony life span compared to all other groups. Our data suggest that genotypic diversity may reduce fitness of queenless honey bee colonies, probably due to reproductive conflicts among subfamilies after queenloss.