Further studies on pre-imaginal olfactory conditioning in insects

Abstract

Although normally repelled by the odor of peppermint, flies, of Drosophila melanogaster, which have been reared on a medium containing 0.5% peppermint essence are markedly attracted by the odor of this substance in an olfactometer. Conditioning brought about in this way gradually becomes extinct if the insects are isolated and has practically disappeared in about 6 days. Washing the fully-fed larvae, or newly formed puparia, free from the medium does not eliminate the conditioning effect although it reduces it to some extent. The author concluded that a change in the responses of the adult can be brought about by an influence operating only during the larval life. Exposure of the adult to the odor of peppermint immediately after emergence from the pupa brings about a positive conditioning even though the odor is not specifically associated with any particular favorable quality of the environment.