Mate finding in the forest cockchafer, Melolontha hippocastani, mediated by volatiles from plants and females

The response of the forest cockchafer, Melolontha hippocastani F. (Coleopte ra, Scarabaeidae), towards volatiles emitted by different host plants and c onspecifics was tested in field experiments during the flight period at dus k. Funnel traps containing artificially damaged leaves from the host plants Carpinus betulus L. and Quercus rubra L., as well as from the non-host pla nt Prunus serotina Ehrh. caught significantly more beetles than empty contr ol traps. On the other hand, traps baited with undamaged leaves from Q. rub ra did not catch significantly more beetles than empty control traps. On th e other hand, traps baited with undamaged leaves from Q. rubra did not catc h significantly more beetles than empty controls. Leaves from C. betulus da maged by beetle feeding did not attract more beetles than artificially dama ged leaves. By use of gas chromatography coupled with electroantennographic detection (GC-EAD) electrophysiological responses of males and females wer e shown for Is typical plant volatiles. A synthetic mixture of selected typ ical green plant volatiles was also highly attractive in the field. A total of 9982 beetles was caught during the field experiments, among them only 3 3 females. This suggests that attraction to damaged foliage during flight p eriod at dusk is male-specific. Field experiments testing the attractivenes s of female M. hippocastani towards conspecific males by employing caged be etles and beetle extracts indicated that males of M. hippocastani use a fem ale-derived sex pheromone for mate location. On wired cages containing eith er unmated feeding females, or unmated females without access to foliage, o r feeding males in combination with extracts from unmated females, signific antly more males landed during the flight period than on comparable control cages containing feeding males or male extracts. A possible scenario of ma te location in M. hippocastani involving feeding-induced plant volatiles an d a female-derived sex pheromone is discussed.