Le tissu adipeux de Rhodnius prolixus (Stål.). Étude histochimique et ultrastructurale chez les larves du 5e stade et chez les imagos

Abstract

A histochemical and ultrastructural study of the fat body of Rhodnius prolixus was done on fifth-instar larvae and adults of both sexes, 6 days after a blood meal. In larvae, fat cells are rich in glycogen and lipid droplets and contain very little protein secretion. The rough endoplasmic reticulum (RER) contains only short saccules although free ribosomes are numerous. The fat body of adult females lacks glycogen and is characterized by an active protein secretion which is not figured as granules. Deep invaginations of the basal plasma membrane delimit wide surfaces of stacked profiles of RER. In adult males, some cytological aspects of the fat body are similar to those of female tissues but the RER is much less extended. Sexual dimorphism of the Rhodnius fat body is thus not pronounced. Brief starvation of females induces a reduction of the cytoplasm in fat cells; the RER mainly regresses and lysosomes are formed by autophagic processes.