Transgenerational genotoxic effects of gamma radiation on Aedes aegypti (Diptera: Culicidae): Implications for programs with the Sterile Insect Technique

Abstract

The Sterile Insect Technique (SIT), which uses ionizing radiation, is a promising approach for suppressing Aedes aegypti, a major vector of arboviruses. However, limited knowledge of the transgenerational effects of gamma radiation may compromise the long-term effectiveness of SIT programs. This study investigated the impact of gamma irradiation on male Ae. Aegypti, and its consequences for fecundity, fertility, and genotoxicity across three generations (F0, F1, and F2). Male pupae were irradiated with 20, 30, 40, and 50 Gy and then mated with non-irradiated females. Fecundity and fertility were quantified for the parental and filial generations, and genotoxicity was assessed using the micronucleus assay in larval neuroblasts, adult male Malpighian tubules, and adult female oocytes. Radiation induced a dose-dependent reduction in fertility, reaching near-complete sterility (97.1%) at 50 Gy. Micronucleus formation confirmed genotoxic effects, particularly at 30 and 40 Gy, in both somatic and germline tissues. Heritable damage was evident in F1 and F2 generations, with sex-specific patterns suggesting differences in DNA damage repair and retention, providing new evidence that gamma radiation induces inheritable genomic instability in Ae. aegypti and confirming 50 Gy as an effective sterilizing threshold for SIT applications. The micronucleus assay proved to be a reliable and sensitive biomarker for detecting inherited genomic alterations, supporting its use in quality control and cytogenetic monitoring. These findings inform SIT dose optimization and long-term biosafety protocols.

Keywords: Aedes aegypti; Gamma irradiation; Micronucleus assay; Sterile insect technique (SIT); Transgenerational genotoxicity; fertility.