Effects of diet and activity on lipid levels of adult Mediterranean fruit flies

The objectives of this study were to determine whether adult Mediterranean fruit flies, Ceratitis capitata Wiedeman (Diptera: Tephritidae), are capable of synthesizing lipids, and whether adult diet affects this ability. Lipid levels in females fed protein and carbohydrate or carbohydrate alone declined significantly from emergence to the fourth day of life and then rose back to teneral levels on the fifth day, before oviposition took place on the sixth day. In males fed protein and carbohydrate, lipid levels initially declined as males aged and then stabilized. In carbohydrate-fed males lipid levels declined following emergence and recovered somewhat by the sixth day. Lipid levels declined significantly when flies underwent post-emergence starvation, but after substantial feeding on the above-mentioned diets they eventually (within 6-7 days) reached teneral levels in all experimental groups. Multivariate analysis of variance revealed that differences in lipid contents are primarily related to the flies' age, which corresponds to the various sex-specific activities these flies exhibit. Average lipid investment in eggs was found to equal teneral lipid levels in females. Without lipogenic abilities, oviposition would completely deplete female lipid reserves. We conclude that adult medflies are capaple of lipid synthesis, and that this capability is modulated by individual and sex-specific activity patterns.