A phytoscreen identifies a garlic compound as a deterrent of mating and egg laying in Drosophila and mosquitoes

Abstract

One means of controlling insect disease vectors and pests is with compounds that manipulate their behavior. An extraordinary variety of phytochemicals, i.e., compounds produced by plants, activate insect chemosensory systems. Fruits and vegetables present a source of compounds that are inexpensive and safe. A “phytoscreen” of 43 fruits and vegetables identified garlic as a potent deterrent of mating and egg laying in Drosophila. Diallyl disulfide, a garlic compound, deters both behaviors. Mating and egg-laying effects depend on taste and the TrpA1 channel. Garlic inhibits mating and egg laying in Aedes vector mosquitoes and mating of the tsetse fly Glossina morsitans. Garlic exposure increases expression of Drosophila head genes, including female-specific independent of transformer (fit), which encodes a satiety hormone that is essential for the effect of garlic on egg-laying preference.