GAMMA-RADIATION EFFECT ON PRODUCTION OF 4 PHEROMONAL COMPONENTS OF MALE MEDITERRANEAN FRUIT-FLIES (DIPTERA, TEPHRITIDAE)

An analytical method enabling the collection and gas chromatographic analysis of delta-1-pyrroline that is released from calling males of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was developed. Using this procedure along with previously reported methods for the analyses of geranyl acetate, ethyl-(E)-3-octenoate, and E,E-alpha-farnesene, we compared pheromone production among fruit-reared, factory-reared fertile, and factory-reared sterile male Mediterranean fruit flies in Guatemala. There were no significant differences in pheromone production (ng per male per hour) from 0600 to 1400 hours. In collections made from 1400 to 1700 hours, however, factory-reared fertile males produced significantly more of the three major terpene components (geranyl acetate, ethyl-(E)-3-octenoate, E,E-alpha-farnesene), whereas the factory-reared sterile males produced significantly more of the four-component blend (the three terpenes plus delta-l-pyrroline) than fruit-reared males. Sterile males produced a significantly higher percentage of ethyl-(E)-3-octenoate, based on the four component pheromone blend, during the 1000- to 1400-hour collections. Thus, the primary difference in pheromone production among the tested flies was that the fruit-reared males produced pheromone over a shorter time during the day. Gamma radiation did not affect adversely the amount of total pheromone produced but did affect component ratios in the pheromone blend.