Electroantennogram response of two western corn rootworm (Coleoptera: Chrysomelidae) adult populations to corn and soybean volatiles

The western corn rootworm, Diabrotica virgifera virgifera LeConte, has adapted to crop rotation in parts of Illinois and Indiana with females now laying eggs in soybean, Glycine max L., fields in addition to corn, Zea mays L., fields. The electroantennogram (EAG) responses of females from the rotation-adapted population (Illinois) were not significantly different than the EAG responses of females from the 'normal' population (Missouri) for any of nine individual volatile treatments evaluated except to (E,Z)-2,6-nonadienal. However, females from the rotation-adapted population had nominally greater EAG responses than females from the 'normal' population for eight of nine treatments. This difference was significant when volatile treatments were combined to analyze the main effect of corn rootworm populations. Differences between populations were consistent across volatile treatments, and the volatile treatments x populations interaction was not significant for the analyses of data from females or males. The EAG responses of males from the rotation-adapted corn rootworm population were not significantly different than the EAG responses of males from the 'normal' population for any of the individual volatile treatments evaluated or in the combined analysis.