Cape honeybees, Apis mellifera capensis, police worker-laid eggs despite the absence of relatedness benefits

Abstract

In the Cape honeybee, Apis mellifera capensis, workers lay diploid (female) eggs via thelytoky. In other A. mellifera subspecies, workers lay haploid (male) eggs via arrhenotoky. When thelytokous worker reproduction occurs, worker policing has no relatedness benefit because workers are equally related to their sister workers' clonal offspring and their mother queen's female offspring. We studied worker policing in A. m. capensis and in the arrhenotokous African honeybee A. m. scutellata by quantifying the removal rates of worker-laid and queen-laid eggs. Discriminator colonies of both subspecies policed worker-laid eggs of both their own and the other subspecies. The occurrence of worker policing, despite the lack of relatedness benefit, in A. m. capensis strongly suggests that worker reproduction is costly to the colony and that policing is maintained because it enhances colony efficiency. In addition, because both subspecies policed each others eggs, it is probable that the mechanism used in thelytokous A. m. capensis to discriminate between queen-laid and worker-laid eggs is the same as in arrhenotokous A. m. scutellata.