Species-specific blends of shared pheromone components prevent cross attraction among sympatric species of cerambycid beetles (subfamily Lamiinae)

Research over the last decade has revealed extensive pheromonal parsimony within the large beetle family Cerambycidae, with closely related species producing the same or very similar pheromone components. Sympatric species in the subfamily Cerambycinae, that share pheromone components, are known to avoid cross attraction by differing in seasonal and/or circadian flight period, or due to minor pheromone components that serve as synergists for conspecifics or antagonists for heterospecifics. However, much less is known about the pheromones of species in the subfamily Lamiinae. In this article, I summarize research to identify pheromones of three species of lamiines that are native to eastern North America, and to test the hypothesis that cross attraction is averted by differences between species in pheromone chemistry. Males of the study species produced 6,10-dimethyl-5,9-undecadien-2-one (“geranylacetone”), as well as (E)-6,10-dimethyl-5,9-undecadien-2-ol (“fuscumol”) and/or (E)-6,10-dimethyl-5,9-undecadien-2-yl acetate (“fuscumol acetate”), but varied in the stereochemistry of the latter two compounds. That is, male Astyleiopus variegatus (Haldeman) produced S- fuscumol and S- fuscumol acetate, Astylidius parvus (LeConte) produced R,S- fuscumol and R-fuscumol acetate, while Lepturges angulatus (LeConte) produced R,S fuscumol acetate. Field bioassays showed that geranylacetone was a powerful synergist for A. variegatus and L. angulatus, and that attraction of beetles to traps was generally consistent with the chemical composition of volatiles released by males. For each of the species, cross attraction would be blocked by the absence of critical components, or presence of antagonistic compounds in pheromones of the other species, supporting my hypothesis