Exposure to α-Copaene–Containing Fruits Enhances the Mating Success of Males from a Mass-Reared, Genetic Sexing Strain of the Mediterranean Fruit Fly (Diptera: Tephritidae)

Abstract

Recent research has demonstrated that exposure to ginger root oil (Zingiber officinale Roscoe, which contains α-copaene) significantly increases the mating success of mass-reared, sterile males of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). The present study had two main objectives. First, I assessed whether mass-reared males gain an advantage through exposure to natural sources of α-copaene following their release into the environment. Sterile males from a genetic sexing (temperature sensitive lethal, tsl) strain were exposed to fruits of guava trees (Psidium guajava L.) and the fruits and leaves of orange trees (Citrus sinensis L.) and then competed with wild-like males for copulations with wild-like females. Exposure to oranges increased the mating success of tsl males in tests conducted 1 or 3 d after exposure, but exposure to orange tree leaves had no effect. Exposure to guavas yielded inconsistent results: tsl males tested 3 d after exposure showed enhanced mating success, but those tested 1 d after exposure did not. Second, to more closely mimic conditions characteristic of sterile male releases, I measured the mating success of massreared males (exposed or unexposed to a source of α-copaene) when competing against wild males exposed to a natural source of α-copaene. In these tests, exposed tsl males were outcompeted by wild-like males but to a lesser degree than non-exposed, tsl males. Implications of these findings for the sterile insect technique against C. capitata are discussed.