A Pre-Exposure to Male-Specific Compound γ-Hexalactone Reduces Oviposition in Bactrocera oleae (Rossi) (Diptera: Tephritidae) Under Laboratory Conditions

The olive fruit fly <i>Bactrocera oleae</i> (Rossi) (Diptera: Tephritidae) is regarded as the most harmful pest insect for olive trees worldwide. In order to control olive fruit fly populations and mitigate the damage and economic losses they produce, the development of novel strategies to control the olive fruit fly within an integrated pest management scope has become a major concern. Here we show that a 24-h pre-exposure to the male-specific <i>γ</i>-hexalactone significantly reduces the oviposition on an artificial substrate. The number of eggs per female laid by those females pre-exposed to 1 mg of <i>γ</i>-hexalactone was significantly reduced (6.8 ± 6.1 eggs/female) in comparison to naïve (i.e., non-exposed) females (22.4 ± 10.9 eggs/female), yielding a mean oviposition activity index (OAI) of -0.56 ± 0.22. Contrarily, no significant effect was observed when females were pre-exposed to 0.5 mg of compound, even though the number of eggs per female (14.2 ± 6.3) was lower than that of naïve females, resulting in a mean OIA of -0.24 ± 0.17. Overall, this research represents a preliminary basis for delving into the potential of <i>γ</i>-hexalactone for being used as an oviposition disruptant, albeit further research is still required to address this issue.