Synergistic and Inhibitory Interactions between Methyl Eugenol and Cue Lure Influence Trap Catch of Male Fruit Flies, Bactrocera dorsalis (Hendel) and B. cucurbitae (Diptera: Tephritidae)
Males of the oriental fruit fly, Bactrocera dorsalis (Hendel) and the melon fly, B. cucurbitae (Coquillett), are attracted to methyl eugenol (ME) and cue lure (CL), respectively. These lures, when mixed with a toxicant, are widely used to detect and suppress populations of these agricultural pests. The objective of this study was to assess the effectiveness of (1) traps baited with both ME and CL (mixed or presented separately on adjacent wicks), and (2) traps baited with a single lure but placed in the same tree as a trap containing the alternate lure (1 or 3 m apart). Jackson traps were placed in a mixed orchard on Oahu, Hawaii, and the numbers of released (marked) and wild males were recorded. Traps baited with ME and CL (mixed or separate) captured significantly fewer B. dorsalis males than traps baited with ME alone. CL placed 1 m from ME-baited traps in the same tree also reduced the number of B. dorsalis males captured. Conversely, ME appeared to increase capture of B. cucurbitae males, and traps baited with the 2 lures (mixed but not separate) captured significantly more released males than traps baited with CL alone. Also, ME placed 1 m (but not 3 m) from CL-baited traps increased the trap catch of released B. cucurbitae males. Results are discussed from the perspectives of management and evolution of Bactrocera species.