Abstract
Drosophila suzukii Matsumura, an endemic pest in southeast Asia, has
invaded Europe and the U.S.A. Unlike most of its closely related sibling species,
the serrated ovipositor of D. suzukii permits ovipositing in undamaged fresh fruits.
In the present study, volatiles are identified from host plants that are potentially
involved in D. suzukii host recognition and oviposition behaviour. It is shown that
mated females are attracted to volatiles emitted from intact fruits. The antennally-active
suite of compounds released from the fresh fruits is identified by gas chromatography
coupled with electroantennographic detection, as well as gas chromatography-mass
spectrometry. In olfactometer bioassays, mated females are significantly attracted to
an electroantennographically active volatile, isoamyl acetate, when tested at 10 μg of
synthetic compound in a rubber septa, which has a release rate comparable to that of
fresh fruits. In addition, a genomic survey shows that D. suzukii not only possesses the
full repertoire of genes encoding odorant receptors activated by isoamyl acetate in D.
melanogaster, but also that one of the genes, OR67a, is represented by five duplicated
copies. These results indicate that D. suzukii uses olfactory cues to select oviposition
sites. The identification of volatiles emitted by host fruits that attract D. suzukii may aid
in the development of a selective and efficient synthetic lure for monitoring this pest. As
a close relative of Drosophila melanogaster, D. suzukii provides a unique opportunity for
understanding the physiological mechanisms involved in the shift of this species from
use of rotten to ripe fruits for oviposition.