Chemosensory receptor expression in abdomen tip of female codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae)

Authors: Walker, William; CATTANEO, ALBERTO - SWEDISH UNIVERSITY OF AGRICULTURAL SCIENCES; Stout, Jennifer; EVANS, MACKENZIE; GARCZYNSKI, STEPHEN - FORMER ARS EMPLOYEE

Submitted to: Insects
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2023
Publication Date: 12/14/2023
Citation: Walker Iii, W.B., Cattaneo, A.M., Stout, J.L., Evans, M.L., Garczynski, S.F. 2023. Chemosensory receptor expression in abdomen tip of female codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae). Insects. 14(12):948. https://doi.org/10.3390/insects14120948.
DOI: https://doi.org/10.3390/insects14120948

Interpretive Summary: The codling moth, Cydia pomonella, is a major global agricultural pest insects of apple pear and walnut. For codling moth, like most insects, behaviors are largely influenced by the chemical senses, namely taste and smell. Detection of taste and smell compounds from the environment is mediated by multiple different families of proteins that function as taste and smell receptors. Manipulation of codling moth behaviors by using specific smell compounds in the orchards has been a successful approach to reduce damage in the orchards they infest. This approach, however, has largely targeted male behaviors. In this report, researchers at the USDA-ARS in Wapato, WA, and the Swedish University of Agricultural Sciences in Lomma, Sweden, sought to learn more about the smell and taste receptors that influence female behaviors, since it is the females that lay the eggs to propagate the next generation. Specifically, they examined gene expression of the smell and taste receptors in female codling moth abdomen tip organs involved in egg-laying behaviors. They identified sets of both smell and taste receptor genes expressed in the abdomen tip that are likely candidates to influence egg-laying decisions, and also determined that expression of some of these receptors is increased or decreased after mating. These results increase our knowledge about the genes that can influence codling moth female behaviors. Future research will study the function and role of individual receptors with the aim of identifying taste and smell compounds that can be used to manipulate female codling moth behaviors in the orchards.

Technical Abstract: In insects, the chemical senses influence most vital behaviors, including mate seeking and egg laying; these sensory modalities are predominantly governed by odorant receptors (ORs), ionotropic receptors (IRs), and gustatory receptors (GRs). The codling moth, Cydia pomonella, is a global pest of apple, pear, and walnut, and semiochemically based management strategies limit the economic impacts of this species. The previous report of expression of a candidate pheromone-responsive OR in female codling moth ovipositor and pheromone glands raises further questions about the chemosensory capacity of these organs. With an RNA-sequencing approach, we examined chemoreceptors’ expression in the female codling moth abdomen tip, sampling tissues from mated and unmated females and pupae. We report 37 ORs, 22 GRs, and 18 IRs expressed in our transcriptome showing overlap with receptors expressed in adult antennae as well as non-antennal candidate receptors. A quantitative PCR approach was also taken to assess the effect of mating on OR expression in adult female moths, revealing a few genes to be upregulated or downregulating after mating. These results provide a better understanding of the chemosensory role of codling moth female abdomen tip organs in female-specific behaviors. Future research will determine the function of specific receptors to augment current semiochemical-based strategies for codling moth management.