The Sterile Insect Technique (SIT) is a successful autocidal control method that uses ionizing radiation to sterilize insects. However, irradiation in normal atmospheric conditions can be damaging for males, because irradiation generates substantial biological oxidative stress that, combined with domestication and mass-rearing conditions, may reduce sterile male sexual competitiveness and quality. In this study, biological oxidative stress and antioxidant capacity were experimentally manipulated in Anastrepha suspensa using a combination of low-oxygen conditions and transgenic overexpression of mitochondrial superoxide dismutase (SOD2) to evaluate their role in the sexual behavior and quality of irradiated males. Our results showed that SOD2 overexpression enhances irradiated insect quality and improves male competitiveness in leks. However, the improvements in mating performance were modest, as normoxia-irradiated SOD2 males exhibited only a 22% improvement in mating success compared to normoxia-irradiated wild type males. Additionally, SOD2 overexpression did not synergistically improve the mating success of males irradiated in either hypoxia or severe hypoxia. Short-term hypoxic and severe-hypoxic conditioning hormesis, per se, increased antioxidant capacity and enhanced sexual competitiveness of irradiated males relative to non-irradiated males in leks. Our study provides valuable new information that antioxidant enzymes, particularly SOD2, have potential to improve the quality and lekking performance of sterile males used in SIT programs.
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V.S.D. received a fellowship from the International Atomic Energy Agency (BRA16024) and a scholarship from the Brazilian Coordination for the Improvement of Higher Education Personnel (CAPES). This work was supported, in part, by NSF DEB 1639005, NSF IOS 1257298, the Florida Agricultural Experiment Station, and the joint FAO/IAEA CRP Dormancy Management to Enable Mass-rearing to DAH, as well as AFRI Research Initiative Education and Workforce Development Grants 2015-67012-22793 and 2015-67012-25339 and by the Biotechnology Risk Research Grants Program Assessment Grant 2017-33522-27068 from the USDA National Institute of Food and Agriculture to N.M.T., the Emmy Noether program of the German Research Foundation SCHE 1833/1-1 to M.F.S., USDA-NIFA-AFRI Grant No. 2016-67013-25087 to A.M.H.
Dias, Vanessa S.; Cáceres, Carlos; Parker, Andrew G.; Pereira, Rui; Demirbas-Uzel, Güler; Abd-Alla, Adly M. M.; Teets, Nicholas M.; Schetelig, Marc F.; Handler, Alfred M.; and Hahn, Daniel A., "Mitochondrial Superoxide Dismutase Overexpression and Low Oxygen Conditioning Hormesis Improve the Performance of Irradiated Sterile Males" (2021). Entomology Faculty Publications. 226.