Response of Nontarget Insects to Methyl Eugenol, Cue-Lure, Trimedlure, and Protein Bait Bucket Traps on Kauai Island, Hawaii, USA

Captures of nontarget insects inside fruit fly (Diptera: Tephritidae) traps placed in native habitats at three localities on Kauai Island, Hawaiian Islands were evaluated. Significantly greater nontarget capture rates were found for traps separately baited with four different attractants, methyl eugenol (five species and two morphospecies), cue-lure (two species), trimedlure (three species and one morphospecies), and protein bait traps (one species and one morphospecies) compared to unbaited control traps. These findings suggest that nontarget insects are attracted to those types of fruit fly traps. However, because of the presence of large numbers of scavenger flies captured in our traps, it appears that attraction may have partially been due to lure and protein bait, and, in part, to decaying insects accumulating inside the traps. Nonetheless, fruit fly traps placed in environmentally sensitive habitats should be used sparingly, so as not to place a strain on populations of rare endemic species.