Response of Male Queensland Fruit Fly (Diptera: Tephritidae) to Host Fruit Odors

Abstract

The surveillance and management of Dacini fruit fly pests are commonly split by fly gender: male trapping focuses on the dacine ‘male-lures’, whereas female trapping focuses on lures based on host-fruit volatiles. Although the males of several Dacini species have been reported to be attracted to host fruit volatiles, the option of using host-fruit traps for males has, to date, been ignored. Males of the cue-lure responsive fruit fly Bactrocera tryoni (Froggatt) have been recorded as responding to host-fruit volatile blends, but it is not known how frequently this happens, if it is age-dependent, or the strength of the response relative to cue-lure throughout the year. Here, we conducted an olfactometer experiment to test the lifetime (weeks 1–15) response of B. tryoni males to the odor of tomato, a known host of this fly, and compare catches of wild males to tomato-based traps and cue-lure traps in the field. Bactrocera tryoni males started to respond to tomato odor as they sexually matured (2 to 3 wk olds) and thereafter showed consistent olfactory response until advanced age (15 wk). In the field, wild males were captured by tomato-based traps throughout the year at a level not significantly different from cue-lure traps. The reason for the consistent B. tryoni male response to host fruit odor at this stage is not known, but it certainly occurs at a level greater than can be continued to be ignored for both basic and applied research.

A polyphagous, tropical insect herbivore shows strong seasonality in age-structure and longevity independent of temperature and host availability

“…Flies from the field were live captured following their attraction to BioTrap (V2 X type) baited with cue-lure (4-(4-acetoxyphenyl)-2-butanone), a commonly used attractant for surveillance and monitoring of male B. tryoni 37 , 44 or freshly cut slices of ripe tomato, Lycopersicon esculentum Mill, to which males also respond 71 . On each sampling occasion, four cue-lure and four tomato-based traps were hung in fruiting orchards at 8.00 am in the morning and collected five hours later at 1.00 pm.…”

“…Because of methodological constraints, it was impossible to collect female flies and all the captive cohorts consist of male flies only. Once sexually mature, males B. tryoni response to cue-lure and tomato was constant until 12 weeks 75 and 15 weeks 71 respectively. Therefore, with respect to the experimental need to sample from the field to an unbiased age estimate 70 , our sampling will not recover sexually immature males (sexual maturation occurs at approximately 10 days of age in B. tryoni 76 ), and so the presence of very young flies will be under-estimated in our study.…”