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The defensive behavior of 52 hybrid honeybee (Apis mellifera L.) colonies from four sets of crosses was studied and compared with that of European and Africanized bee colonies. Colonies containing F1 hybrid workers were obtained through reciprocal crosses between European and Africanized bees. The total number of stings deposited by workers in a moving leather patch in 1 min was recorded. In each of the four sets of crosses, bees from hybrid colonies of Africanized paternity left more stings in leather patches than bees from hybrid colonies of European paternity. Results strongly suggest paternal effects of African origin increasing the defensive behavior of hybrid colonies. Although some degree of dominance was observed for high-defensive behavior in one of the four sets of crosses involving European paternity, most of the dominance effects reported in the literature appear to be the result of paternal effects. Several hypotheses to explain this phenomenon, as well as the implications of these effects on the fitness and breeding of honeybees are discussed. [ABSTRACT FROM AUTHOR]

Honeybees have an age-based division of labour that is influenced by genetic variability for the tendency to perform specific tasks. Individuals in a honeybee colony comprise diverse genotypes and their interactions can influence task allocation. Colonies from an African race (Africanized honeybees, AHB, Apis mellifera scutellata Ruttner) usually produce a much stronger defensive response than do European races of honeybees (EHB), and these races may differ in how individuals are allocated to the tasks of guarding and stinging. We observed guarding behaviour in colony environments that varied in proportions of genotypes (AHB, EHB) and population size. In large colonies, AHB showed much greater guarding persistence (number of days guarding) than EHB; hybrids were intermediate. In another series of experiments, three families each of AHB and EHB were cofostered in colonies with different AHB: EHB ratios, then tested in large and small colonies. In colonies of both sizes, colony environment interacted with both famly and type (AHB or EHB) for propensity to guard. Individuals of both types guarded more persistently in large colonies, but family and type both interacted with environment. EHB were more likely to initiate guarding bouts in low-AHB colonies, but persistence did not change with environment. AHB were insensitive to effects of environment for the tendency to initiate guarding behaviour, but were more persistent in high-AHB environments. EHB and AHB may differ in how they allocate individuals to guarding. The positive reinforcement of behaviour that occurs in high-defensive environments and in large populations could cause a stronger stinging response through alarm pheromone recruitment. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. [Copyright &y& Elsevier]