Cape honey bees, Apis mellifera capensis, are unusual in that both queenright and queenless laying workers regularly reproduce parthenogenetically. This progeny may be female or male and the former may give rise either to workers or to queens. Some laying workers also exhibit shifts in the relative pheromonal composition of the mandibular gland secretion from worker-like to queen-like and effectively mimic queens in their ability to suppress queen cell construction and ovarial development in other workers. When introduced into colonies of other races such as A. m. scutellata (through active socio-parasitic invasion by the bees themselves, inadvertently by beekeepers or for experimental reasons) such worker bees evoke retinue responses from host workers and the latter eliminate their own queen in preference for the Cape laying worker in their midst. The recent introduction of Cape honey bees into the provinces of north-eastern South Africa has seriously affected commercial beekeeping with A. m. scutellata.