The digestive system of the leafhopper Bucephalogonia xanthophis (hemiptera, cicadellidae): the organization of the luminal membrane complex

Abstract

A detailed morphofunctional study of the digestive system of the xylem-sucking hemipteran, Bucephalogonia xanthophis is presented. The foregut is formed by a simple tube, the esophagus. The midgut starts at the filter chamber (Fc), progressing then to more posterior conical (cM) and tubular regions (tM). the Fc is made up of the apposition between the anterior and posterior midgut, along with the proximal segments of the four Malpighian tubules, allowing the concentration of nutrients in the middle midgut. A dilated rectum constitutes the hindgut to which the distal ends of the Malpighian tubules associate. histologically, the foregut is formed by a simple epithelium, composed of flattened cells covered by a cuticle. The FC cells have a reduced cytoplasm with their apical surface modified into microvilli, whereas the basal plasma membrane presents several invaginations associated with mitochondria. the cM and tM enterocytes exhibit ultrastructural signs of secretory activity. Instead of a perimicrovillar membrane, present in most hemipteran species, B. xanthophis show an entirely different luminal membrane complex, the flame-like membranes. This complex originates from constrictions of the microvillar tips which form membranes that project into the midgut lumen, keeping their association with the microvilli.