Responses of fruit flies (Diptera: Tephritidae) to new attractants in Papua New Guinea

Male fruit fly attractants - cue-lure and methyl eugenol (ME) - have been used successfully for decades in the monitoring and control of species of Dacini (Dacinae) fruit flies (Bactrocera, Zeugodacus and Dacus). However, many species, including several pests, are non-responsive to these lures. Field tests of new compounds are therefore worthwhile, particularly in areas of high species diversity where multiple species attractions can provide additional information on lure function. Recent field tests of new male attractants (isoeugenol, dihydroeugenol, methyl-isoeugenol and zingerone) and food-and host-based lures (cucumber volatile blend and Cera Trap(R)) in Australia resulted in discoveries of lure responses for 'non-responsive' species. In this study, these new lures were field tested for the first time in Papua New Guinea (PNG) for attractiveness to 'non-responsive' species, including the guava pest Bactrocera obliqua and cucurbit pests Zeugodacus atrisetosus and Z. decipiens. Testing was conducted in the National Capital District (NCD) and Kerevat on the island province of East New Britain. Of the 'non-responsive' pest species, B. obliqua was trapped three times at isoeugenol and once at methylisoeugenol. This is the first record of B. obliqua responding to male lures. Zeugodacus decipiens was significantly attracted to Cera Trap. Five undescribed species responded to zingerone and one to the eugenol analogues. The ME-responsive B. musae and B. umbrosa responded differently to the three eugenol analogues in Kerevat and NCD, with both species responding more strongly to methyl-isoeugenol in NCD, although their response to ME was similar in both locations. Intraspecific differences in lure response were also noted between this study and that recorded previously in other countries. The cue-responsive B. frauenfeldi, B. neohumeralis and Dacus axanus were previously trapped at zingerone in Australia, and the ME-responsive B. dorsalis was trapped at zingerone in Malaysia, but these species, while caught at their respective lures, were not recorded at zingerone in this study. The findings from this study have implications for quarantine monitoring for the 'non-responsive' B. obliqua and Z. decipiens in Australia, highlight that there may be intraspecific variation in male lure response and provide further information on these novel male lures' activity.