Senescence and learning in honeybee (Apis mellifera) workers.

Foraging by honeybee workers was investigated from the moment of the first foraging flight until death. To minimise the influence of factors other than senescence the foragers were trained to collect food from an artificial flower close to their hive. During each foraging trip the workers repeatedly visited an artificial flower, collecting one microlitre of 50% sugar solution per visit. During the first 50 flights the mean time taken to collect one portion of food decreased significantly and the number of visits to the artificial flower per flight increased significantly. During flights following the 50th flight, the mean time taken to collect one portion of food increased significantly and the number of visits to the artificial flower per flight decreased significantly. The results confirm earlier observations that the foraging behaviour of honeybee workers is not only influenced by learning, but also by the effects of senescence.