Zingerone improves mating performance of Zeugodacus tau (Diptera: Tephritidae) through enhancement of male courtship activity and sexual signaling.

Certain male fruit flies from the genera Bactrocera and Zeugodacus (Diptera: Tephritidae) actively forage for floral semiochemicals produced by some endemic Bulbophyllum orchids found in tropical and subtropical forests. These floral semiochemicals are largely classified as either phenylbutanoids (e.g., raspberry ketone (RK)) or phenylpropanoids (e.g., methyl eugenol (ME)). Zingerone (ZN) is a phenylbutanoid recently found that structurally resembles ME and RK, both of which are phytochemicals commonly used as male attractants in fruit fly control programmes. It was previously shown that feeding on ME and RK increased the mating success of certain tephritid fruit flies, specifically in B. dorsalis and B. tryoni males, respectively, through enhancement of sexual signaling. However, ZN, which acts as a metabolic enhancer to increase male courtship activity in B. tryoni, did not show the same effect. As fruit fly-phytochemical lure interactions are unique and species-specific phenomena, this study seeks to elucidate the ecological significance of ZN feeding to Zeugodacus tau in terms of sexual signaling. We demonstrate here that ZN feeding by Z. tau males enhanced female attraction and subsequent mating success by increasing male courtship, and the attractiveness of the sexual signals in both wind tunnel and semi-field cage bioassays. In addition, we also demonstrated temporal effects on male behaviour in relation to the amount of lure intake. However, feeding on ZN did not appear to affect the total time spent in copula for Z. tau. This is the first report showing an important role of ZN in increasing courtship activity as well as enhancement of sexual signaling in Z. tau males.