Antennal and Behavioral Responses of Drosophila suzukii to Volatiles from a Non-Crop Host, Osyris wightiana

Simple Summary The spotted-wing drosophila Drosophila suzukii, native to Southeast Asia, has become a new threat for cultivated and wild soft-skinned fruits in both their native and invaded areas. The attractiveness of volatiles from fresh ripening and ripe fruits of cultivated crops, such as raspberry, blueberry, strawberry, and cherry, has been extensively studied. To date, however, little attention has been paid to the non-crop host of D. suzukii. In this study, we collected headspace volatiles from ripe fruits of a wild non-crop host, Osyris wightiana, and identified seven compounds attractive to D. suzukii from the fruit volatiles. A blend of the seven active compounds captured a significant amount of female and male D. suzukii in field, suggesting that the blend can be used to develop an attractant for management and monitoring of D. suzukii. Drosophila suzukii (Diptera: Drosophilidae) infests a variety of commercial fruits, including cherries and other soft-skinned fruits. After the cropping season of most cultivated crop hosts, it heavily infests the fruit of a wild host-plant, Osyris wightiana in southwest China. Here, we employ gas chromatography-electroantennographic detection (GC-EAD) together with behavioral bioassays and a trapping experiment to identify volatile semiochemicals emitted by O. wightiana that are involved in D. suzukii attraction. GC-EAD recordings of D. suzukii antenna showed responses to 13 compounds, including alpha-pinene, 3-methylbutyl acetate, 2-hexanol, E-beta-ocimene, Z-3-hexenol, beta-caryophyllene, alpha-humulene, and six unidentified compounds. The flies were attracted by seven individual EAD-active compounds at low doses (0.01 and 0.1 mu g), but were repelled at high doses (10 and 100 mu g). In a similar manner, a blend of seven EAD-active compounds at low doses (0.1 and 1 mu g) was attractive to female flies, but became repulsive at high doses (10 mu g). The low dose of the blend was as attractive as the fruit volatiles, although both were less attractive than the fruits. The blend attracted both female and male D. suzukii and other Drosophila flies. The percentage of D. suzukii out of all flies captured by the blend was significantly greater than that captured by the control. These results indicate that the EAD-active volatile compounds emitted by fruits of O. wightiana play an important role in D. suzukii attraction, and have the potential to be used for management of D. suzukii.

Automated summary

The study identified seven attractive compounds emitted by the ripe fruits of the non-crop host Osyris wightiana for the spotted-wing drosophila Drosophila suzukii. A blend of these compounds successfully captured a significant number of D. suzukii in the field, indicating its potential for attractant development and pest management.