A multi-disciplinary approach for developing tools to monitor invasive buprestid beetle species

Buprestid beetles (Coleoptera: Buprestidae), which were previously considered to be minor forest pests, have received substantial attention recently due to the widespread ash tree mortality associated with the North America introduction of the emerald ash borer, Agrilus planipennis from Asia. At the same time, geographic expansions of forest buprestid species associated with other hosts have been noticed, causing concern about potentially similar destructive outcomes. Attempts have been made to understand the host-finding and mating behaviors of these forest buprestids in order to develop detection and management tools, with a focus primarily on A. planipennis. A complex sequence of chemical and visual signals appears to mediate such behaviors, which has been difficult to mimic in an effective trapping approach. Both sexes appear to be attracted to the tree canopy as a result of host-produced volatile compounds. Once in the canopy, males visually seek and fly directly onto stationary females from a distance of up to 1 meter, an event which immediately precedes attempts to copulate. The subsequent copulation attempts by the males are mediated by sex-specific cuticular hydrocarbon signals. Similar visually-mediated approaches toward dead models have also been observed in other tree-dwelling buprestids such as Agrilus cyanescens, A. subcinctus, A. biguttattus, A. sulcicollis, and A. angustulus. While the extent of similarities of both visual and chemical signals shared by these species and A. planipennis has not been fully explored, it is becoming clear that the visual signal that induces attraction to a female is broadly tuned, exhibiting substantial cross-species attraction. Despite subtle differences in coloration patterns, all of these species generate an intense spectral signal using the refractive properties of repetitive layering of the elytral cuticle. Further investigation into both the means of generation and response to the visual signal, as well as the chemical ecology of these species, may provide advances in trapping technologies for the detection of all tree-feeding Buprestids.