Bacterial volatiles as potential new attractants for the Island Fly (Dirioxa pornia) (Tephritidae: Phytalmiinae)

Many fruit fly species have a detrimental impact on food production. Lure and kill and mass trapping methods are becoming more important for crop protection, but currently, Island Fly (Dirioxa pornia) does not have a specific attractive lure for males and females. This study is initial research into olfactory responses to gut bacteria emissions. Fruit flies use olfactory cues for locating bacteria that assist in their development cycle. The ingestion of food together with naturally occurring bacteria allows a microbiome to form in their intestinal tract. This project investigated the gut microbiome of laboratory reared Island Flies, the chemical composition of the volatiles released from these microbes by GC-MS and the attractiveness of Island Flies to the volatile isolates using Y-tube olfactometry, electroantennography and wind tunnel experiments. All bioassay results of Island flies showed a rapid attraction towards the identified bacterial volatile isolates of Bacillus sp. and deterrence towards Citrobacter freundii. Other bacterial isolates of Bacillus subtilis, Klebsiella oxytoca and Providencia rettgeri showed low to moderate attractions respectively. Bacillus sp. uniquely had alkanes, some alcohols, aldehydes and nitrogen containing compounds while C. freundii had many sulphur-containing compounds and acids. Further studies on these compounds may assist in the development of a microbial-based lure.