Contact Sex Pheromone Activity of Synthetic Gomadalactones in Male White-Spotted Longhorn Beetle, Anoplophora malasiaca (Coleoptera: Cerambycidae).

Abstract

The elytra of females of the white-spotted longhorn beetle, Anoplophora malasiaca (Coleoptera: Cerambycidae), are coated with a contact sex pheromone, which was previously shown to be composed of at least three chemical groups. Individually, the chemical groups had little pheromonal activity, but a blend of all three exhibited activity equal to that of the crude female extract. Two groups are female-specific aliphatic hydrocarbons and ketones, which were previously synthesized and confirmed to elicit mating behavior. The third group consists of three lactones, gomadalactones A, B, and C, whose chemical structures were previously identified. These have now been synthesized, and the contact sex pheromone activities of synthetic gomadalactones A, B, and C, and the diastereomer of gomadalactone C, were tested in bioassays in this study. When tested in combination with synthetic hydrocarbons and ketones at the same doses as found in female elytra extract, the individual gomadalactones and a blend showed potent pheromonal activity equivalent to that of the crude extract of the elytra of female beetles. This completes the identification of the essential components of the contact sex pheromone of A. malasiaca. Redundancy of components in the hydrocarbon and ketone groups required to elicit mating behavior was observed previously, and this was also true for the gomadalactones.