Most night-flying moth species locate mates through production of, and response to, a very exact blend of two or more odorous chemicals called pheromones. Females with atypical blends of the pheromones have been shown to be less attractive to males than females with the species common blend. Similarly, rare males that respond to atypical blends have been found to be at a disadvantage in finding mates. Evolutionary forces appear to be selecting against any change in the pheromone communication system. If evolutionary forces are indeed selecting against change then we are left with the question of how evolution could have resulted in the current existence of thousands of species of moths that have unique pheromones. The proposed research addresses this question by determining the genetic basis for control of pheromone production/response and uses genetic crosses to produce atypical females and males to determine if all alterations in the genes controlling these traits are selected against.
There are many existing traits of organisms, like the moth pheromones, that require the combined action of a number of genes to function properly, and on the surface it appears as if evolutionary forces would not have favored their development. There is a need to genetically dissect some of these traits to experimentally examine how evolution may have acted on single components of these traits. The moth system will serve as a model for such an analysis. The moths studied are crop pests, so the knowledge gained from these studies will help in designing better mating disruption tools that control these pests.
