Abstract
In laboratory tests, two inbred lines of honeybees (Apis mellifera) different in colony defensive behaviour were shown to differ in their initial general activity level, the time to react to isopentyl acetate, and the initial intensity of the reaction. Evaluation of an F1 and backcrosses to both lines indicated that a more responsive phenotype was dominant to a less responsive phenotype in all three characteristics. The degree of dominance for time to react was estimated as 0·502 and the heritability as 0·681. It was estimated that 2 or 3 loci controlled each of the three components of behaviour.