Intra- and interspecific genetic variation in the gustatory perception of cucurbitacins by diabroticite rootworms (Coleoptera: Chrysomelidae)

An assay designed to detect the limit of response to the phagostimulant cucurbitacin B was used to quantify intra-and interspecific variation in cucurbitacin perception in adults of the striped cucumber beetle, Acalymma vittatum (F.); the western corn rootworm, Diabrotica virgifera virgifera LeConte; the banded cucumber beetle, D. balteata LeConte; and the spotted cucumber beetle, D, undecimpunctata howardi Barber. By controlling ontogenetic and environmental factors such as gender, age, reproductive status, prior consumption of cucurbitacins, and hunger, the assay was able to identify geographically based genetic differences in the mean and standard deviation of the limit of response to cucurbitacin B within and among the species tested. Possible sources of this variation and its implications for the use of cucurbitacin-based toxic baits against rootworm pests are discussed.