Aging and habituation of the tarsal response in Drosophila melanogaster.

The measure of the waning of an unconditioned response, viz. the extension of the proboscis in response to repetitive tarsal stimulations by sucrose, has been conducted in young and old Drosophila melanogaster as a mean to estimate habituation. The same percentage of young and old flies reaches the defined criterion of habituation. The number of trials to reach habituation does not vary with age. That habituation experiment does not reveal any form of perseveration in the aged Drosophila, contrary to what has been shown in mammals. These results could be due either to the fact that old flies are not more perseverative than young ones or to the fact that the habituation test used is perhaps too simple.