Fuscumol and Geranylacetone as Pheromone Components of Californian Longhorn Beetles (Coleoptera: Cerambycidae) in the Subfamily Spondylidinae

In field trials testing attraction of cerambycid beetles to a blend of known pheromone components plus host plant volatiles, several species in the subfamily Spondylidinae were attracted to baited traps, suggesting that one or more components of the blend might constitute their pheromones. Here, we describe laboratory and field experiments aimed at identifying the actual pheromone components produced by these species. Analysis of headspace odors collected from male Tetropium abietis (Fall) (Coleoptera: Cerambycidae) contained (S)-fuscumol as a single component, whereas Asemum nitidum (LeConte) (Coleoptera: Cerambycidae) males produced both (S)-fuscumol and geranylacetone, and Asemum caseyi (Linsley) (Coleoptera: Cerambycidae) produced only geranylacetone. In field trials testing fuscumol, fuscumol acetate, and geranylacetone as individual components or in blends, in combination with host plant volatiles, A. nitidum were attracted to blends of fuscumol and geranylacetone, T. abietis were attracted to fuscumol alone, and A. caseyi were attracted to geranylacetone alone. Fuscumol acetate did not appear to be either attractive or inhibitory. These results, along with previous catches of spondylidine species in traps baited with fuscumol, provide evidence that fuscumol and geranylacetone are likely to be relatively common pheromone structures for species in the subfamily Spondylidinae.