Research on insect pheromones has enabled their use in ecologically-sound pest control in agricultural and public health systems. Pheromonal communication has also served as an important model for our understanding of the mechanisms of signal diversification and speciation in animals. However, most research has focused on female-emitted pheromones, largely ignoring close-range male-produced pheromones which are important for species-recognition and female mate choice. This project addresses two major questions: (1) How does natural variation in close-range male sexual signals affect female choice? (2) What are the evolutionary consequences if the production of male sexual signals is biochemically and genetically linked to production of female signals? Specifically, this project will chemically identify the close-range male pheromones in two moth species using a combination of behavioral and analytical approaches, quantify the magnitude of intraspecific variation in the male pheromones, and evaluate what features of the male pheromone contribute to female mate choice. The comparative project will concentrate on two ecologically and agriculturally important species, Spodoptera frugiperda (Fall Armyworm) and Heliothis virescens (Tobacco Budworm). A unique asset is that each species consists of two strains with distinct female pheromone blends. Results of this investigation will be critical not only for understanding the roles of reciprocal signaling and mate choice in the evolution of sexual communication systems in animals, but will also lead to a better understanding of how the evolution of mating preferences can lead to premating isolation among populations, and ultimately to the origin of new species. With additional support from NSF's Office of International Science and Engineering, this project will train a postdoctoral researcher, a graduate student, and undergraduate students in a unique international collaborative project with the Max Planck Institute for Chemical Ecology in Jena, Germany. These trainees will participate in community science education outreach programs.
