Fig. 3. (A) Learning rate of H. virescens females showing the conditioned response (proboscis extension) to different concentrations of the odorants racemic linalool, ß-ocimene and ß-myrcene in extinction tests. The tests were performed 15 min after a 10-conditioning trial procedure. A lower threshold for learning and for the maximum proportion of insects responding were obtained for racemic linalool as compared to the two other odorants. Insect numbers were 36-39 for all groups except for the additional group conditioned to racemic linalool at 0.001 mg (N=49). (B) Dose-response relations as electroantennograms (EAG) for the different concentrations of the three odorants racemic linalool, ß-ocimene and ß-myrcene obtained in H. virescens females. The responses are given as percentages of the response to 10 mg racemic linalool and as the average of the responses to the two parallel test series in five female moth antennae. The lowest concentration was tested in two individuals only. The mean response to the control (air) was subtracted from the odorant responses, which explains the slightly negative response values for some of the lower odorant concentrations. The dotted line shows the mean response to the other control (hexane evaporated on filter paper). Error bars indicate the standard error of means. (C) The learning rate (% proboscis extension in A) plotted as a function of the EAG response (% of the 10mg racemic linalool standard in B) showed a significant correlation (Pearson R correlation coefficient).