β-cyclocitral synergizes the response of adult Drosophila suzukii (Diptera: Drosophilidae) to fruit juices and isoamyl acetate in a sex-dependent manner.

Semiochemicals play a pivotal role in the location, evaluation, and utilization of hosts by herbivorous insects. Mixtures of host plant-derived compounds are often required to elicit appropriate levels of response to olfactory stimuli. In multiple-choice bioassays, we characterized the response of adult Drosophila suzukii to foliage- and fruit-based synthetic compounds tested alone and in association with grape and tart cherry juices, and assessed whether synergistic interactions among olfactory stimuli are involved in the olfactory-driven behavior of D. suzukii. Our results established (1) significant attraction of females (but not males) to β-cyclocitral and isoamyl acetate when tested singly, (2) the presence of a synergistic interaction between β-cyclocitral and cherry juice only for females, and (3) the presence of a synergistic interaction between β-cyclocitral and isoamyl acetate but only in the case of males. Our findings increase our understanding of male and female D. suzukii olfactory responses to synthetic compounds and fruit juices as sources of attractants. Combinations of foliage- and fruit-based compounds may be needed to increase SWD attraction.