Fig. 4. Mean electroantennogram responses (in mV) from Colorado potato beetles elicited by a 10ng injection of (S)-enantiomer, (R)-enantiomer and racemic CPB I. Responses of males and females were not significantly different and were therefore combined. Values are means ± S.E.M. (N=6, three males and three females). Columns with different letters are significantly different, P<0.01, Duncan's multiple-range test.