Effects of thelytokous worker reproduction on kin-selection and conflict in the Cape honeybee, Apis mellifera capensis

Abstract

Apis mellifera capensis workers are able to produce female eggs by the process of thelytoky, whereas the workers of other races of honeybee and most other eusocial Hymenoptera produce males only (arrhenotoky). The maximization of inclusive fitness has been studied in eusocial arrhenotokous species, but not in thelytokous ones. Thelytokous worker offspring are female, consequently the kin-structure of colonies is altered. This difference leads to changes in kin-value asymmetries and kin-selection. Following from these changes many of the predictions regarding conflict in thelytokous species differ quantitatively or even qualitatively from those for arrhenotokous species. In A. m. capensis inclusive fitness arguments predict more conflict between workers over reproductive dominance, especially when the colony is queenless. Some of the unique traits of Gape honeybee workers upon queen-loss, for example: (i) extreme aggression amongst workers; (ii) very rapid development of ovaries; and (iii) queen-like pheromones in workers upon queen-loss can be explained as responses to such selection. It is predicted that workers will remove (police) less of their fellow workers’ eggs than other races.