The effects of artificial diets on the anterior intestinal cell ultrastructure of Rhodnius prolixus (Hemiptera:Reduviidae).

Mated female Rhodnius prolixus were fed diets of washed rabbit erythrocytes (RBC), rabbit plasma, edestin (a plant storage protein) in Ringer's or Ringer's solution alone. All diets contained 1 mM ATP. The effects of these diets on anterior intestinal cell ultrastructure were evaluated and compared to changes induced by normal blood feeding. Separation of basal labyrinth membranes was induced earlier after Ringer's-feeding than with all other diets. Normal modifications of the rough endoplasmic reticulum (rer) were observed only in response to blood components, while rer cisternae were swollen shortly after edestin feeding. Normal modifications to lysosomal structure were induced by plasma and RBC feeding, but changes were also observed with the non-blood diets. Production of extracellular membrane layers (ECML) by the microvilli occurred in response to each diet: plasma-feeding induced considerably early ECML formation, but prolonged ECML proliferation was greatest after RBC feeding. Storage inclusions were most prominent in cells of plasma-fed insects. Initial changes in the basal labyrinth may be induced by a high luminal fluid: protein ratio; in the rer by blood factor(s); and in lysosomes by plasma factor(s). Gut distention initiates ECML production but continued proliferation is regulated by the midgut contents.