Evolution of the Sex Pheromone Communication System in Ostrinia Moths

SIMPLE SUMMARY: Moths typically rely on sex pheromone communication to find a mate. This involves the production of species-specific sex pheromones by females (the signaller) and the corresponding selective detection by conspecific males (the receiver). A key question in the evolution of the pheromone communication system is how the female signals can diversify and still be tracked by the receivers over the process of speciation. The genus Ostrinia, which comprises 20 species worldwide including several well-recognised agricultural pests, is an attractive model in the study of the evolution of sex pheromone communication, as the closely related species and strains provide an ideal example of ongoing speciation. This review presents a comprehensive overview of the research on pheromone communication in different Ostrinia species over the past four decades, from the identity and biosynthesis of pheromones in the females to the molecular and neuronal basis of the pheromone perception in males. The evolutionary insights from these studies are discussed and the directions for future research are outlined. ABSTRACT: It remains a conundrum in the evolution of sexual communication how the signals and responses can co-ordinate the changes during speciation. The genus Ostrinia contains several closely related species as well as distinctive strains with pheromone polymorphism and represents an example of ongoing speciation. Extensive studies in the genus, especially in the species the European corn borer O. nubilalis (ECB), the Asian corn borer O. furnacalis (ACB) and the adzuki bean borer O. scapulalis (ABB), have provided valuable insights into the evolution of sex pheromone communication. This review presents a comprehensive overview of the research on pheromone communication in different Ostrinia species over the past four decades, including pheromone identification and biosynthesis, the ligand profiles of pheromone receptor (PR) genes, the physiology of peripheral olfactory sensory neurons (OSNs) and the projection pattern to the antennal lobe. By integrating and comparing the closely related Ostrinia species and strains, it provides an evolutionary perspective on the sex pheromone communication in moths in general and also outlines the outstanding questions that await to be elucidated by future studies.