Multiple channels of DEET repellency in Drosophila

Hao Guo, Kishor Kunwar, Dean Smith

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

BACKGROUND: N,N-Diethyl-meta-toluamide (DEET) is the prophylactic insect repellent used most widely to inhibit insect bites. Despite its use since 1944, the mechanism of DEET repellency remains controversial. Here, we revisited the role of smell and taste in DEET repellence using Drosophila as a model. RESULTS: Analysis of the responses of individual olfactory receptor neuron (ORN) classes to DEET reveals that 11 ORNs are activated and two are inhibited by this compound. Blocking individual ORN classes in the antenna does not block DEET repellence. This argues against the existence of a single ORN mediating DEET repellence in Drosophila. Activation of all ORCO-expressing neurons using channelrhodopsin favors attraction, not repellence, in behavioral valence. We also demonstrate that gustatory neurons are highly sensitive to DEET. We used RNA interference to screen candidate receptors encoded by gene families involved in the detection of bitter compounds, including 34 gustatory receptors (Grs), 14 ionotropic receptors (Irs), five pick-pocket subunits (PPKs), three transient receptor potential ion channels (TrpA, TrpL, Painless) and one metabotropic glutamate receptors gene (DmXR). We saw striking defects in DEET-mediated oviposition behavior when expression of either Gr32a or Gr33a was inhibited. CONCLUSION: Our findings support a multimodal mechanism for DEET detection in fruit flies and indicate a prominent role for taste detection mediating DEET repellence.

Original languageEnglish (US)
Pages (from-to)880-887
Number of pages8
JournalPest Management Science
Volume76
Issue number3
DOIs
StatePublished - Mar 1 2020

Keywords

  • DEET
  • Drosophila melanogaster
  • gustatory receptor
  • odorant receptor
  • odorant receptor neurons

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Insect Science

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