Responses of queenright and queenless workers of Apis cerana to 9-keto-2(E)-decenoic acid, a pheromonal constituent of the mandibular gland

Abstract

In dequeened honeybee colonies ovarian activation occurs in some workers, and the pheromonal bouquets of these laying workers become more queen-like. In the Asiatic honeybee, Apis cerana, we compared the amounts of 9-keto-2(E)-decenoic acid (9-ODA), a mandibular gland pheromone component, between non-laying workers from queenright colonies and laying workers from queenless colonies and, further, applied synthetic 9-ODA to workers to determine whether workers discriminate workers with activated ovaries based on the level of this compound. Levels of 9-ODA were higher in laying workers from dequeened colonies than in non-laying workers from queenright colonies. In both queenright and queenless colonies, more workers treated with 9-ODA were attacked by other workers than were control-treated workers. These results suggest that detection of pseudoqueens in A. cerana is mediated by changes in 9-ODA.