The surface morphology of the midgut cells of Rhodnius prolixus Stål (Hemiptera: Reduviidae) during blood digestion.

The surface morphology of the midgut cells of Rhodnius prolixus is examined using scanning electron microscopy. Before feeding, the microvilli are devoid of any extracellular structures and can be observed in both fracture faces and surface views. By 3 days after feeding, patches of extracellular membrane layers are observed on the surface of the midgut cells and by 7 days the extracellular membrane layers form an incomplete sheet overlying the microvilli, such that the microvilli are no longer visible in surface view. At 15 days after the blood meal the membrane layers are well developed in the intestine forming a continuous sheet, while in the crop the layers are not as completely developed. The results complement previous studies on the midgut ultrastructure of R. prolixus. The extracellular membrane layers are thought to function as a peritrophic membrane, allowing the spatial separation of digestive processes.