Electrophysiological responses of Queensland fruit fly, Bacterocera tryoni, were investigated to identify the olfactory receptor neurons (ORN) in the antennae and corresponding active volatile compounds, using the single sensillum recording technique and 52 test compounds including methyl methyl eugenol, cuelure and raspberry ketone. We found that different classes of olfactory sensilla and ORNs are present in the antennae of B. tryoni. Most of the ORNs appeared to have narrow response spectra, exhibiting specialized responses to one or a few volatile compounds among the 52 compounds tested. In this study, ORNs specialized for ammonia, nonanal, isopentanol, ethyl acetate, indole, phenol, 2,5-dimethylpyrazine and 2-coumaranone, respectively, have been identified. A class of ORNs exhibited highly specialized responses to methyl eugenol. A preliminary field trapping test conducted in New Caledonia to evaluate the behavioral activities of the olfactory active compounds indicated a blend of three synthetic compounds is attractive to female B. tryoni.

• Kye Chung Park(New Zealand Institute for Plant and Food Research)