Fig. 4. Results from the first field-trapping experiment, 23-28 April. In each treatment, 5 µg of an electrophysiologically active compound was added to the pheromone blend of Eriocrania semipurpurella [reference blend (Ref.) 50 µg of (R,Z)-6-nonen-2-ol and 50 µg of (S,Z)-6-nonen-2-ol]. The graph shows the number of males of the two species E. semipurpurella and E. cicatricella caught per trap. Values are means + S.E.M. (N=15). ^*Significantly different from the reference blend (Ref.) (P<0.001) (Mann—Whitney U-test); NS, no significant difference from the reference blend.