Evolution of Sex Pheromone Communication in Plant-Feeding Scarab Beetles

Abstract

Throughout the world, herbivorous scarab beetles (Coleoptera: Scarabaeidae) include various economically important pests in agriculture, horticulture, and forestry. Both larvae and adults damage plants by feeding on underground and aerial parts, respectively. Despite this group’s economic importance as agricultural pests and the high demand for safer agrochemicals, our knowledge of their pheromone chemistry was very limited until recently. This was mainly due to the lack of uniform and consistent bioassays, which precludes the identification of these semiochemicals. This barrier has been overcome by coupling gas chromatography—electroantennographic detection (GC—EAD) (Leal et al. 1992a) or gas chromatography—behavior bioassay (GC—BB) (Leal et al. 1992b) with simplified laboratory bioassays or field tests. The use of these techniques has allowed our group to identify the sex pheromones of some scarab beetles of economic importance in Japan. Although only a handful of sex pheromones have been identified to date, our findings suggest possible scenarios for the evolution of pheromone communication in this group.