Molecular Mechanism of a Conserved Odorant Receptor in Detecting a Repellent Signal in the Rice Moth Corcyra cephalonica

The rice moth Corcyra cephalonica, a highly destructive pest found worldwide, with a wide-ranging diet and robust reproduction, severely damages various stored foods. A sensitive olfactory system is essential for insect behavioral perception, odorant receptors (ORs) play a crucial role in detecting volatile chemical cues in the living environment of insects. However, the reports on the identification and functional analyses of ORs in C. cephalonica are currently lacking. In this study, we identified CcepOR13, which clusters into the conserved lepidopteran OR42 ortholog family. TEVC recordings revealed its conserved function, and phenylacetaldehyde, 2-phenylethanol, cinnamaldehyde, and pentanal were identified as its main ligands. Behavioral experiments revealed that among these four ligands, C. cephalonica exhibited avoidance behavior only in response to 2-phenylethanol, and after dsRNA-CcepOR13 treatment, its electrophysiological and avoidance responses to 2-phenylethanol were significantly reduced. Our findings indicate that CcepOR13 is essential for 2-phenylethanol recognition by C. cephalonica, suggesting that the development of repellents for biological control is warranted.