REGIONAL AND FUNCTIONAL-DIFFERENTIATION IN THE INSECT FAT-BODY

Insect fat body historically has been considered a single tissue with multiple and diverse metabolic functions. Recent findings indicate tha t functionally distinct regions of fat body exist in some insects and that these regions often have unique morphologies. Regionally differen tiated fat bodies in Lepidoptera have been associated with the segrega tion of synthetic and storage activities. The loss of biosynthetic cap acity for storage proteins at the beginning of metamorphosis is the co nsequence of the histolysis of a larval specific histotype, whereas th e histotype that accumulates storage proteins persists into the adult stage. In Diptera, functional histotypes are arranged along the anteri or-posterior axis and between the larval and adult stages. Based on th ese models, we predict that the use of immunological and molecular pro bes will lead to the identification of regionally and functionally dif ferentiated fat body histotypes in many insects.