Effect of age on the mating propensity of the mediterranean fruit fly (Diptera : Tephritidae)

The effect of age on the mating propensity of both wild and laboratory-reared Mediterranean fruit flies, Ceratitis capitata (Wiedemann) was investigated under laboratory and field cage conditions. The optimal age for wild flies ranged from 7 to 13 days, whereas in laboratoryreared flies it was between 3 and 5 days old. Virgin flies were selective and more prone to mate than flies that were held with both sexes combined and therefore, had a chance to mate before the test. The difference among ages in laboratory-reared flies was significant only in virgin flies. Virgin females showed a tendency to increase their mating propensity as they got older, whereas virgin males showed a bimodal pattern, with peaks at 4 and 11 days old. When flies of both strains and different ages were combined, laboratory-reared females accounted for 72% of the all the matings and most matings were by 4-day-old females. Wild males accounted for 67% of all the matings and the maximum number of matings were by 10-day-old males. For quality control purpose, flies should be virgin and at their optimal age, this will produce more robust data for statistical analysis. For control purpose, it is recommended to release sterile flies at 1-2 days old, because flies in the field will be at their maximum mating propensity. Our results support the concept that releasing males only will make the Sterile Insect Technique more effective, since sterile males will be virgin and therefore, more prone to mate.