Influence of the odour of fruit, yeast and cue-lure on the flight activityof the Queensland fruit fly Bactrocera tryoni (Froggatt) (Diptera : Tephritidae)

Certain volatile substances increased the frequency of flights by Bactrocer a tyroni (Froggatt) in laboratory arenas with artificial foliage, irrespect ive of the presence or absence of a visual cue (red fruit model). The odour of guava and iso-amyl acetate, but not nerol, increased the flight frequen cy of mature females. The odour of yeast autolysate had a similar effect on immature females (previously starved of the substance), but had no effect on mature females (previously fed on it). The flight activity of mature mal es increased in the presence of the odour of cue-lure. Ten per cent of flie s landed on a red model within 7.5 min when in the presence of an odour, wh ereas only 1.7% did so when there was no odour. No flies landed on transpar ent models regardless of the presence or absence of odour..