AN ELECTROANTENNOGRAM APPARATUS FOR TESTING THE ACTIVITY OF SEMIOCHEMICALS ON THE OLIVE BEETLE, PHLOEOTRIBUS-SCARABAEOIDES (COLEOPTERA, SCOLYTIDAE) - FIRST RECORDINGS OF THE RESPONSE TO ETHYLENE

An electroantennogram (EAG) apparatus for testing the activity of pheromones of the olive beetle, Phloeotribus scarabaeoides, is described. This inexpensive device is suitable for whole antennal recording from scolytids. The modification of the amplifier and sample injection system, described previously, eliminate parasitic noise and improve the recording of the EAG signal. Results from previous studies revealed significant beetle attraction to a source releasing ethylene. Serial solutions of 2-chloro-ethyl phosphonic acid were tested, and 10% acetic acid served as a standard. A significant variation in amplitude of depolarization was found among the different concentrations of 2-chloro-ethyl phosphonic acid tested. Maximum depolarization was elicited at a concentration of 0.1% in both males and females. In general, no statistical differences in responses were found between males and females, but females showed a significantly lower threshold of response.