Honey bee queens do not count mates to assess their mating success

Authors: Simone-Finstrom, Michael; TARPY, DAVID - North Carolina State University

Submitted to: Journal of Insect Behavior
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2018
Publication Date: 3/8/2018
Citation: Simone-Finstrom, M., Tarpy, D.R. 2018. Honey bee queens do not count mates to assess their mating success. Journal of Insect Behavior. 31(2):200-209. doi: 10.1007/s10905-018-9671-3.

Interpretive Summary: Honey bee queens mate with an extremely high number of males during their mating flights, up to 40 in some cases. Given that mating with a large number of males reduces the relatedness of a queen’s offspring, and therefore all the workers in the colony, the reasons for this extreme mating behavior have been under much scrutiny. The potential ability for a queen to assess the number of males that she has mated with and adjust her flight behavior accordingly is a significant question to help to determine if a queen’s mating number is determined by this ability to count mates or if it is regulated by some other aspect of mating. Here we observed queen mating flights and only permitted them to have one successful flight, during which she can mate with multiple males. We examined the mating success of queens that initiated egg-laying after one flight, and therefore did not attempt to have a second mating flight, and compared that to the mating success of queens that attempted more flights after a successful mating flight. We found that queens that had one successful mating flight mated with the same number of males as those that had one successful flight and attempted subsequent flights. This finding suggests that queens are not adjusting their mating flight behavior based on the number of mates during their initial flight. These results provide insight into how queen mating behavior is regulated.

Technical Abstract: The mating system of honey bees (genus Apis) is extremely polyandrous, where reproductive females (queens) typically mate with 12 or more males (drones) during their mating flight(s). The evolutionary implications for hyperpolyandry have been subject to considerable debate and empirical testing because they run counter to kinship theory that predicts indirect fitness benefits for highly related nestmates. The ability of queens to gauge and adjust their reproductive success is therefore important for selection to act on queen mating number at both the evolutionary (colony-level) and proximate (individual-level) timescales. We observed the mating flight activities of 80 queens in their respective mating nucleus hives each with a modified entrance that restricts flight attempts. We also attached a small weight (0, 16, or 38 mg) onto each queen’s thorax as a means of imposing additional flight costs. We then compared queens that were restricted from taking multiple mating flights to those that started oviposition after a single flight for their mating numbers as quantified by microsatellite analyses of their respective worker offspring. We found that neither additional weight nor restricted mating attempts had any significant effect on the effective mating frequencies of the experimental queens during their single mating flight. This observation suggests that queens are not adjusting their nuptial flight activity according to their precise mating number during their flight. These findings provide insights into the proximate regulation of honey bee queen mating behavior and the fitness consequences of hyperpolyandry at the colony level.