Insect olfactory repellents: is there a gustatory contribution?

Abstract

Insect repellents provide protection from biting insects including mosquitoes by affecting the olfactory system. As such, the majority of research carried out to understand the mechanisms behind insect repellency has focused on olfaction. Recent molecular evolutionary studies performed on olfactory receptors demonstrated that these proteins have evolved directly from gustatory receptors. The goal of my study is to determine if repellent compounds interact with the insect gustatory system. I carried out electrophysiological studies on the yellow-fever mosquito Aedes aegypti (Diptera: Culicidae) to determine if insect repellents stimulate receptor cells housed within gustatory sense organs (sensilla) located on the mouthparts. Electrophysiological studies show the presence of at least three gustatory receptor neurons (GRNs), one of which is activated by repellent compounds. The information in this study reveals a mechanism by which insect repellents act on the gustatory system, potentially leading to the design of more effective insect repellents.