Pre-exposure affects the olfactory response of Drosophila melanogaster to menthol

A modification of the trap assay (Woodard et al., 1989) was used to evaluat e the response of Drosophila melanogaster (Meigen) to food media containing menthol. Dose-response curves for flies to mentholic foods were produced f or flies that had been pre-exposed to menthol, during development and adult life, and flies that had not been exposed to menthol before the assay. Men tholic food media were less attractive to Drosophila than plain food medium . Rearing flies on a medium containing menthol reduced their aversion to so me concentrations of menthol. The rearing effect was not simply due to lowe red general activity levels resulting from developing in a medium containin g menthol. There was a threshold concentration of menthol in the rearing me dium below which we found no induced behavioural change.