Functional Characterization of Pheromone Receptors in the Beet Webworm, Loxostege sticticalis (Lepidoptera: Pyralidae)

SIMPLE SUMMARY: The moth Loxostege sticticalis (Lepidoptera: Pyralidae) is a typical migrant insect pest found in North America, Eastern Europe, and Asia. The natural pheromone compounds of adult moths are involved in courtship and mating behavior. In this article, we examine the peripheral mechanisms of sex communication, demonstrating that the pheromone receptor (PR) LstiPR2 responds specifically to the major sex pheromone compound E11-14:OAc, which results in the activation of the “a” neuron in sensilla trichodea. The other four LstiPRs showed no response to any sex pheromone compounds. This study will contribute to a new, environmentally friendly strategy for integrated pest management of L. sticticalis. ABSTRACT: Lepidopteran insects mainly rely on sex pheromones to complete sexual communications. Pheromone receptors (PRs) are expressed on the olfactory receptor neurons (ORNs) of the sensilla trichodea and play an essential role in sexual communication. Despite extensive investigations into the mechanisms of peripheral recognition of sex pheromones in Lepidoptera, knowledge about these mechanisms in L. sticticalis remains limited. In this study, five candidate LstiPRs were analyzed in a phylogenetic tree with those of other Lepidopteran insects. Electroantennography (EAG) assays showed that the major sex pheromone component E11-14:OAc elicited a stronger antennal response than other compounds in male moths. Moreover, two types of neurons in sensilla trichodea were classified by single sensillum recordings, of which the “a” neuron specifically responded to E11-14:OAc. Five candidate PRs were functionally assayed by the heterologous expression system of Xenopus oocytes, and LstiPR2 responded to the major sex pheromone E11-14:OAc. Our findings suggest that LstiPR2 is a PR sensitive to L. sticticalis’s major sex pheromone compound, E11-14:OAc. Furthermore, this study offers valuable insights into the sexual communication behavior of L. sticticalis, forming a foundation for further analysis of the species’ central nervous system.