Plant volatile chemicals and insect responses

Abstract

Production and emission of volatile organic chemicals (VOCs) is a general phenomenon in most of the plant communities. Insects respond to plant chemicals in a variety of interesting ways which has tremendous potential in pest management programmes. In a normal state, plants release a spectrum of species-specific VOCs through their leaf, stem, flower, and even root surfaces, and they become host location cues to insects leading to their colonisation on the plant, whereas the plants damaged by insect feeding emit qualitatively and quantitatively different volatiles that become host/prey location signals to the wandering insect natural enemies causing the reduction of the pest population. In addition to this, plant volatiles synergise or deter the insect sex pheromonal activities. Insects possess excellent chemosensory system for detection of volatile chemicals. The advent of electrophysiology, scanning, and transmission electron microscopic techniques made insect sensory physiology/morphology an admirable tool to unravel the mechanisms underlying the insect responses to plant volatile compounds.