Title "Chemoecological investigations of Drosophila suzukii: a new exotic pest attacking cherry and small berry fruits"

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), also called Spotted Wing Drosophila (SWD) is an Asian polyphagous invasive pest, currently spreading worldwide (Northern USA, Middle-Southern Europe). It is considered an important threat to soft skinned fruit cultivations, since females are able to oviposit into undamaged healthy fruits (berries, grapes, cherries), using their serrated ovipositor. The hatched larvae feed inside the fruits, which become unmarketable because of both direct damages and indirect ones (secondary pathogens). Since efficient monitoring and control tools are not yet available for this species, several researches are currently aiming to understand SWD biology, ecology and distribution, in order to develop environmentally safe control strategies, in the perspective of an eco-friendly agriculture. Understanding the chemical ecology of SWD would be a huge advantage to achieve this goal. It’s well known that semiochemicals play crucial roles for many herbivore insects: host plant volatiles can mediate their behaviour in feeding on suitable hosts, locating a mate and/or the oviposition site. The information about SWD chemical ecology is currently poor; that is why numerous studies are in progress to investigate the role of volatile compounds on this pest’s behaviour in order to select attractant compounds (that could be used as baits for mass trapping control strategies) or repellent compounds (useful to be used to inhibit feeding or oviposition). The project will be developed through different phases: - investigations concerning the host susceptibility, aiming to evaluate the specific and varietal susceptibility of cultivated host plants to SWD and to determine the changes in susceptibility during the fruit ripening. - studies aiming to characterize and identify the volatiles emitted by host fruits. Volatile compounds emitted by the host fruits will be extracted and identified (GC-MS). Electroantennographic (EAG, GC-EAD) and behavioural assays (Y-shaped olfactometer, oviposition bioassays) will be carried out on D. suzukii to test the biological activity of the most active compounds. - investigations on intra-specific insect’s interactions, aiming to characterize volatile compounds which could have a potential pheromonal activity in D. suzukii, playing a role in the mate recognition and in the courtship behaviour, to be potentially exploited in sexual communication interference control strategies.