Methoprene treatment reduces the pre-copulatory period in Anastrepha fraterculus (Diptera: Tephritidae) sterile males

Anastrepha fraterculus is a major fruit pest in South America. Ongoing studies support the implementation of the sterile insect technique (SIT) against this pest. Sexual readiness of sterile males is a key point for SIT application. The pre-copulatory period of A.fraterculus males has not been reported before, but it is expected to last several days. An acceleration of sexual maturation was achieved in other Anastrepha species after topical applications of juvenile hormone analogues, like methoprene. Here, we studied the effect of methoprene on male sexual maturation, mating duration and sperm transfer in A.fraterculus as well as the impact of acetone (methoprene solvent) on survival. We also explored a method to deliver methoprene massively. Pheromone-calling and mating ability were evaluated daily from adult emergence, and used as indicators of sexual maturity. Anastrepha fraterculus males showed a long pre-copulatory period (7days approximately), as other Anastrepha species. This process was accelerated after methoprene treatment (2.5g/l), both in non-irradiated and irradiated males which matured 2-3days earlier. Mating duration for methoprene-treated males was longer than for mature untreated males, however, no differences in sperm transfer were detected. Survival was not affected by acetone. Dipping pupae in methoprene allowed emerging males to mature as fast as those receiving topical application as adults. Dipping of pupae is a promising method to deliver massively methoprene and should be further investigated.