Effects of Pre-Release Chilling on the Flight Ability of Sterile Males of the Mediterranean Fruit Fly (Diptera: Tephritidae)

The Sterile Insect Technique (SIT) is used to suppress or eradicate infestations of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann). The success of the SIT depends to a large degree on the ability of sterile males to compete successfully against wild males in obtaining matings with wild females. Sterile males are chilled to allow their transfer to and subsequent storage within the aircraft used for the releases. Here, we describe the results of an experiment that investigated the effects of varying chill duration (at 3–8 °C for 2–6 h) on flight ability of sterile males derived from mass-rearing facilities in Hawaii and Guatemala. Flight ability decreased significantly, and at the same rate, with increasing chill duration for flies from both production facilities. However, for any given chill duration, the Hawaii-derived flies displayed greater flight ability than the Guatemala-derived flies. In addition, there was significant variation in flight ability among daily shipments from both facilities. Nevertheless, the present data clearly reveal that limiting chill duration promotes higher flight performance of released sterile males. Implications of our findings for Mediterranean fruit fly SIT programs are discussed.