Olfactory learning in worker honeybees from queenright and queenless colonies (Apis mellifera carnica Pollm.)

Abstract

In order to study the significance of queen loss in a honeybee colony for the ontogeny of queen pheromone perception, the conditioned proboscis extension response to queen extract (dose of 0.001 queen equivalent) in worker honeybees (Apis mellifera carnica Pollm.) was investigated. Worker bees (newly emerged, 1-, 2-, 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 12-, 14-, 16-, 18- and 20-day-old) from specially formed queenright (with a mated and egg-laying queen) and queenless colonies were studied. Our results revealed a great improvement in olfactory learning of queenright workers during the first three days of adult life. The olfactory learning in queenless worker bees reached its maximum only on the 10th day, i. e. seven days later than in queenright bees. Differences in the levels of conditioned response to the queen extract of queenright and queenless workers were revealed within two to nine days of adult development. Similar differences were revealed in the rate of conditioning of queenright and queenless workers of the same age in the period from three to eight days (except in the rate of conditioning of 6-day-old bees). The conditioned response of workers over 10 days of age was high irrespective of the queen’s presence in the colony. Keywords: Apis mellifera, proboscis extension response (PER), conditioning, honeybee queen, queen pheromone, age