Reproductive biology of scutellata—a proven invader
The reproductive biology of the scutellata-derived 'Africanized honeybee' (hereafter AHB) has been extensively studied in the American neotropics (for an overview and references see Schneider et al., 2004). AHB has been shown to have a strong reproductive advantage over European subspecies.
AHB colonies show a greater emphasis on pollen than nectar collection, and this pollen is rapidly converted into brood. AHB colonies produce more brood per adult worker than other honeybee subspecies, resulting in high growth rates and increased swarm production. Likewise, drone production is high, resulting in a mating advantage of AHB males due to numerical superiority at drone aggregations. Moreover, AHB drones tend to drift into other colonies, thereby suppressing drone production by the host colony. Male migration from AHB colonies into European ones was almost certainly an important factor in the displacement of European subspecies in the Americas.
During queen rearing (prior to swarming or to replace the mother queen), AHB virgin queens may have a competitive advantage in colonies that have both AHB and non-AHB parentage. This advantage arises from AHB virgin queens developing faster than queens of other genotypes. Thus, if a colony has patrilines arising from both scutellata and non-scutellata males, it is more likely that a virgin from a scutellata patriline will inherit the colony because they tend to emerge first and kill their rivals.