Sterile but Sexy: Assessing the Mating Competitiveness of Irradiated Bagrada hilaris Males for the Development of a Sterile Insect Technique

<i>Bagrada hilaris</i> (known as painted bug) is a pest native to India, Southeast Asia, and middle and central Africa and was reported as invasive in the southwestern USA, Hawaii, Mexico, South America, and two Mediterranean islands. The feeding activity results in extensive damage to economically important Brassicaceae crops. Among sustainable alternatives to synthetic pesticides, the Sterile Insect Technique (SIT) is considered a promising strategy because it relies on the release of competitive sterile males that can reduce the pest reproduction. In this study, the efficacy of different doses of gamma irradiation (60, 80, and 100 Gy) was evaluated to identify the treatment that would ensure high sterility without compromising the competitiveness of the treated males. Observational tests showed that the doses of 60 Gy and 80 Gy showed no difference in mating times compared to non-irradiated males, in contrast to 100 Gy. Thus, 80 Gy was identified as the most promising dose. For further investigation, tests were conducted under choice and no-choice conditions at 80 Gy for three days. The results showed that irradiated males had a comprehensive higher mating rate than non-irradiated males, and under choice conditions, they were often preferred by females, confirming that SIT has potential as an environment-friendly method for controlling <i>B. hilaris</i>.