Defensive Behaviour and Production of Alarm Pheromone in Honeybees

Abstract

Summary Worker bees of an “aggressive” line (Brown) were more easily alerted to disturbance, and much more responsive to alarm substance, than those of a “gentle” line (Van Scoy). The sting apparatus of Brown workers contained about one-third more isopentyl acetate (IPA) than that of Van Scoy workers. Brown x Van Scoy hybrids responded to human breath and to measured amounts of IPA to the same extent as Van Scoy, leading to the conclusion that the gentle Van Scoy response is due to dominant heredity. Response of the hybrids to disturbance (removing the hive cover) was intermediate, indicating lack of dominance. Production of IPA in the hybrids was very variable, but on the average it resembled that in the Brown, and gave an indication of heterosis.