Lipid and protein loads in pupating larvae and emerging adults as affected by the composition of Mediterranean fruit fly (Ceratitis capitata) meridic larval diets.

The effects of sucrose and amino acid (aa) composition and concentration in meridic larval diets (e.g., partially defined at the chemical level) was examined on several parameters of Mediterranean fruit fly (Medfly) development. Lipid and protein levels of pupating larvae and emerging adults were examined. Different sucrose concentrations in the diet had small effects upon most of the development parameters. However, sucrose concentration significantly affected the ability of larvae to accumulate lipid reserves and proteins. Adults emerging from the different sucrose diets did not significantly differ in their lipid contents and protein loads. Specific deletions of aa from the diet, and general aa concentration, had a strong effect upon the parameters of development and pupating larvae lipids and proteins. Glycine-deletion was the most deleterious, followed by the deletion of all non-essential aa, and serine. High aa concentration in the diet has a detrimental effect upon development. Lipid contents in pupating larvae, and to some extent protein levels, were affected by aa manipulations in the diet. Lipid and protein loads in emerging adults were not significantly affected by aa manipulations. Based on the analysis of lipid frequency distribution it is suggested that the Medfly seems to regulate the level of lipid content in emerging adults within a certain range, regardless of the larval diet history or lipid contents. Proteins do not seem to be regulated as are lipids. These results point to an interesting and unexpected metabolic regulation of energetic resources during metamorphosis of the Medfly.