The influence of paternity on virgin queen success in hybrid colonies of European and African honeybees

When African honeybees, Apis mellifera scutellata, migrate into an area, substantial hybridization occurs with existing European bee populations. However, over time European traits disappear until the populations become predominantly or entirely African. European patrilineal traits could be lost when hybrid colonies raise virgin queens if African-patriline queens have a survival advantage during reproductive competition. We examined queen competition in observation colonies that contained an African (A) or European (E) matriline, and both patrilines. In colonies of either matriline, the virgin queens that survived the elimination process were those that emerged sooner, piped more, eliminated more rivals and received more vibration signals from workers. Hybrid queens had increased piping and vibration rates and greater fighting success than did purebred queens. However, the effects of hybridization were expressed differently in the two matrilines, resulting in significant matriline-by-patriline interactions. In the E-matriline colonies, African-patriline queens emerged sooner, piped more, killed more rivals, were vibrated at higher rates and were more likely to survive the replacement period than were their European-patriline sister queens. In contrast, in the A-matriline colonies, the behaviour of African- and European-patriline queens was highly variable, and the two queen types did not differ for any of the characters examined or the ability to survive the rival elimination period. Thus, African paternity potentially conveys a competitive advantage to queens of European maternity, which would contribute to the spread of African alleles and the loss of European traits in hybrid zones. Furthermore, we observed that vibration signals were produced predominantly by African-paternity workers. The vibration signal may influence the spread of African traits, and this effect may be mediated largely by the behaviour of African-paternity workers. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.