Identification of compounds produced by male hairpencil glands of Heliothinae (Lepidoptera: Noctuidae) and their role in male autodetection and female mate acceptance

Heliothine moths represent some of the world's most important agricultural pest species. Helicoverpa zea (Corn Earworm) and Heliothis virescens (Tobacco Budworm) cause billions in damage and control costs worldwide each year. Due to their economic importance, sex pheromones of many species have been studied for development of management techniques such as trapping for population monitoring. The majority of pheromones identified and studied to date have been female-produced sex pheromones. Less emphasis has been placed on male sex pheromones, associated with abdominal hairpencil structures which are often function in courtship or attract females. My study examines the composition, detection and behavioral role of male H. zea hairpencil compounds in male autodetection and in courtship. Comparative examination of hairpencil blend compositions of H. zea and H. virescens revealed subtle differences in pheromone blend composition produced by males of these species. Electrophysiological testing demonstrated broad antennal neuron response in both males and females of H. zea to nine stimuli, with sexual dimorphism present in each species. Behavioral assays suggested that odors released by male hairpencils are important in mate acceptance by female H. zea and may play a role in mate choice and species isolation. Wind tunnel observations indicate that key H. zea hairpencil odors (hexadecenyl acetate, octadecenyl acetate) also function in mate competition, antagonizing responses of downwind conspecific males following a female sex pheromone plume.