Neurophysiological and behavioral responses of gypsy moth larvae to insect repellents: DEET, IR3535, and picaridin.

Jillian L Sanford,Sharon A Barski,Vonnie D C Shields,Christina M Seen,Joseph C Dickens,Frederic Marion-Poll

doi:10.1371/journal.pone.0099924

Abstract

The interactions between insect repellents and the olfactory system have been widely studied, however relatively little is known about the effects of repellents on the gustatory system of insects. In this study, we show that the gustatory receptor neuron (GRN) located in the medial styloconic sensilla on the maxillary palps of gypsy moth larvae, and known to be sensitive to feeding deterrents, also responds to the insect repellents DEET, IR3535, and picaridin. These repellents did not elicit responses in the lateral styloconic sensilla. Moreover, behavioral studies demonstrated that each repellent deterred feeding. This is the first study to show perception of insect repellents by the gustatory system of a lepidopteran larva and suggests that detection of a range of bitter or aversive compounds may be a broadly conserved feature among insects.

Highlights

The effects of insect repellents have been shown to elicit aversive behavior in numerous insect species through the olfactory system [1,2]
Effects of repellents on deterrent-sensitive gustatory receptor neuron (GRN) A single neuron within the medial styloconic sensillum on the maxillary palps fired in response to DEET, IR3535, and picaridin presented either singly
We demonstrate that insect repellents are detected by a specific GRN in the larva of the L. dispar and the presence of the repellents deters feeding

Summary

Introduction

The effects of insect repellents have been shown to elicit aversive behavior in numerous insect species through the olfactory system [1,2]. While it is known that olfaction plays a major role in mediating the behavioral effects of DEET and other insect repellents, recent research on two selected adult dipteran species clearly demonstrated that repellents may act through the gustatory system [7,10]. These authors demonstrated that two adult dipteran species, the vinegar fly Drosophila melanogaster [10] and the yellow-fever mosquito Aedes aegypti [7] have a gustatory receptor neuron (GRN) housed within the labellar sensilla sensitive to DEET (D. melanogaster) and two other insect repellents, IR3535 and picaridin (A. aegypti). Lee et al [10]

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