Hetero-specific queen retinue behavior of worker bees in mixed-species colonies of Apis cerana and Apis mellifera

Abstract

The retinue behavior of worker bees of Apis cerana cerana and Apis mellifera ligustica in two types of mixed-species colonies were studied to determine whether observed behaviors are pre- or post-speciation developments. In A. cerana queen-led mixed colonies, almost equal numbers of A. cerana workers (53.4±7.4) and A. mellifera workers (51.2±8.1) attended the A. cerana queen; while in A. mellifera queen-led mixed colonies, the A. mellifera queen attracted significantly fewer (47.8±5.9) A. cerana workers than A. mellifera workers (51.9±4.6). Thus about 100 workers in total were attracted to each queen. In pure A. cerana and A. mellifera colonies, the queen attracted 105.8 ± 9.1 and 107.8 ± 11.2 workers, respectively, there being no significant difference between them. Only the pheromones 9-ODA, 9-HDA and 10-HDA of the queens were significantly different and the workers did not show avoidance behavior to either heterospecific queen. Both species of workers were attracted by the queens and engaged in retinue behavior, suggesting that the retinue response was not related to a specific queen pheromone or colony environment. This non-specific queen retinue behavior in the mixed colonies indicates that the queen pheromones can be transmitted among the workers from the two species without any obstacles. We conclude that retinue behavior itself as well as the pheromones of the queens that induce this behavior are both primitive, conserved traits that preceded speciation in apine bees.