A crude cuticular extract from 3450 virgin 9–13 day old female fruit flies(Drosophila virilis), was subjected to chromatography accompanied by bioassay for sex pheromone activity. After three chromatographic steps, fractions containing active monoenes and dienes were obtained. Chemical analysis by infrared absorption, gas liquid chromatography and gas chromatography/mass spectrometry of the active fraction indicated that active monoenes were comprised chiefly of (Z)-11-pentacosene (abbreviated (Z)-11-C25:1), (Z)-13-C27:1’, (Z)-13- and (Z)-14-C29:1. Synthetic monoenes were made, and only (Z)-11-C25:1 elicited good courtship behaviour in maleD. virilis. Therefore it was concluded that (Z)-11-C25:1 was a major sex pheromone. A total of 16.2±1.32 µg of cuticular hydrocarbons was isolated from 10 day old females, including 5.9±0.56 µg of (Z)-11-C25:1. An additive effect was suggested from the higher observed courtship response when using a mixture of active dienes with the active monoene.
sex pheromone courtship behaviour (z)-11-pentacosene fruit fly Diptera Drosophilidae Drosophila virilis