The chemosensory receptors of codling moth Cydia pomonella-expression in larvae and adults

Olfaction and gustation play critical roles in the life history of insects, mediating vital behaviors such as food, mate and host seeking. Chemosensory receptor proteins, including odorant receptors (ORs), gustatory receptors (GRs) and ionotropic receptors (IRs) function to interface the insect with its chemical environment. Codling moth, Cydia pomonella, is a worldwide pest of apple, pear and walnut, and behavior-modifying semiochemicals are used for environmentally safe control. We produced an Illumina-based transcriptome from antennae of males and females as well as neonate head tissue, affording a qualitative and quantitative analysis of the codling moth chemosensory receptor repertoire. We identified 58 ORs, 20 GRs and 21 IRs, and provide a revised nomenclature that is consistent with homologous sequences in related species. Importantly, we have identified several OR transcripts displaying sex-biased expression in adults, as well as larval-enriched transcripts. Our analyses have expanded annotations of the chemosensory receptor gene families, and provide first-time transcript abundance estimates for codling moth. The results presented here provide a strong foundation for future work on codling moth behavioral physiology and ecology at the molecular level, and may lead to the development of more precise biorational control strategies.