ABSTRACT
The sterile insect technique (SIT) is an effective control method for insect pest populations based on the release of male insects sterilized by ionizing radiation to reduce reproduction of targeted females in the field. Although irradiation successfully sterilizes insects, it may induce oxidative stress that can diminish the sexual competitiveness of sterile males. Oxidative stress alters an organism’s physiological state through an imbalance between free radicals and antioxidants. The surplus of free radicals generated by oxidative stress affects various reproductive traits, including courtship displays. In tephritid fruit flies, courtship behavior involves multimodal signaling, incorporating both chemical and acoustic elements that can be negatively impacted by oxidative stress. In this study, we hypothesized that enhancing antioxidant capacity would reduce oxidative stress and improve male courtship behavior in the Caribbean fruit fly, Anastrepha suspensa. We overexpressed a major antioxidant enzyme in A. suspensa, mitochondrial manganese-dependent superoxide dismutase (MnSOD), to test the extent to which increasing antioxidant capacity decreases the adverse effects of oxidative stress on male acoustic and chemical displays after irradiation. The results showed that males overexpressing MnSOD had greater mating success, produced more attractive calling songs, and generated higher quantities of essential pheromone compounds (anastrephin and epianastrephin) than wild-type males. These findings contribute to a better understanding of the evolution of multimodal signaling from a mechanistic perspective as well as point to new directions for improving SIT programs.
