Environmental Modification of Oviposition Behavior in Drosophila

In order to assess the independent effects of larval and adult environments on oviposition site preference in four species of Drosophila (D. melanogaster, D. pseudoobscura, D. immigrans, and D. recens), individuals were exposed as larvae and/or adults to medium containing sodium chloride, ethanol, ethyl acetate, lactic acid, piperidine, or peppermint oil. For the first three species, previous exposure of adults to peppermint oil significantly reduced their aversion to this substance; that is, they appeared to become habituated to it. Adults of D. melanogaster also became habituated to 7% ethanol medium, which is normally repellent to ovipositing females. Finally, an induced preference for piperidine containing medium was exhibited by D. immigrans when they were exposed to such medium as adults. In no case did the larval environment have a significant effect on subsequent oviposition behavior. Buf if adults emerge in the vicinity of their larval environments, the processes of habituation and induced preference can promote local polyphagy, aid in the tracking of fluctuating resources, and facilitate the spread of genes that adapt individuals to particular larval food resources.