Determination of volatile substances in olives and their effect on reproduction of the olive fruit fly

Females of the olive fruit fly Bactrocera oleae lay their eggs on olives mainly using fruit volatile stimuli. Using GC-MS analysis, we determined the chemical composition of the volatile blend emitted from field-collected olive fruit of cv. Megaritiki, at different stages of growth. The identified chemicals were tested in the laboratory with regard to their effect on mating and egg production of the fly. GC-MS analysis demonstrated qualitative and quantitative differences in the headspace blend emitted by the olive fruits. Certain chemicals such as toluene, n-octane, α-pinene, limonene, ethyl hexanol, nonanal n-dodecane, decanal and n-tetradecane were detected in the greatest amounts, irrespective of the growing stage of the fruits. Exposure of the flies to some of these chemicals as noctane and α-pinene, as well as to a mixture consisting of n-octane, α-pinene, limonene, ethyl hexanol, nonanal, n-dodecane, decanal, n –tetradecane favoured mating success and egg production. The results may contribute to the improvement of mass rearing of the fly, through the knowledge of the positive effect that certain fruit volatile chemicals have on fly’s reproduction and a better understanding of the relation between the fly and the host fruit.