INTRASPECIFIC 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 phagostimulan t cucurbitacin B was used to quantify intra-and interspecific variatio n in cucurbitacin perception in adults of the striped cucumber beetle, Acalymma vittatum (F.); the western corn rootworm, Diabrotica virgife ra virgifera LeConte; the banded cucumber beetle, D. balteata LeConte; and the spotted cucumber beetle, D, undecimpunctata howardi Barber. B y controlling ontogenetic and environmental factors such as gender, ag e, reproductive status, prior consumption of cucurbitacins, and hunger , the assay was able to identify geographically based genetic differen ces in the mean and standard deviation of the limit of response to cuc urbitacin B within and among the species tested. Possible sources of t his variation and its implications for the use of cucurbitacin-based t oxic baits against rootworm pests are discussed.