Effect of irradiation on the mating capacity and competitiveness of Drosophila suzukii (Diptera: Drosophilidae) for the development of the sterile insect technique

The sterile insect technique is a new approach for the integrated management of Drosophila suzukii Matsumura (Diptera: Drosophilidae), an invasive pest in North America. We evaluated, under laboratory conditions, the mating capacities and success of male D. suzukii, irradiated at a dose of 120 Gy, with and without competition. We also explored the tendency of females to remate depending if their first mate was irradiated or not. We observed that irradiated males have the same mating capacity as control males, copulating with, respectively, 6.4 ± 1.9 females versus 6.9 ± 2.0 females in a 24-hour period. Irradiated males won the competition 37.5% of times, which is not significantly different from competiveness of control males. Female remating can be considered infrequent and not significantly influenced by male treatment: 7.4% of the females first mated with control males and 18.8% of the females first mated with irradiated males remated when given the opportunity two days and four days after the first mating. Latency before mating and mating duration were not significantly influenced by male treatment, but by presence of male competition. Overall, irradiated males thus seem to be as performant as control males, which is an important condition for a successful sterile insect technique programme.