Midgut morphology and enzymes of the obligate zoophytophagous stinkbug Brontocoris tabidus (Signoret, 1863) (Heteroptera: Pentatomidae)

Abstract

The predatory bug, Brontocoris tabidus (Signoret, 1863), is an obligate zoophytophagous species; it cannot survive for long periods in the absence of plant resources. Understanding its digestive process will help elucidate the ecological and economical significance of this species. This is a study of the morphology and enzymes of the midgut of B. tabidus. The midgut is divided into four distinct regions like other heteropteran insects. In the anterior region, digestive cells are columnar with dilated apices containing unstained granules that contain some Fe and Ca accumulations; a short brush border is evident. In the central region of the midgut, digestive cells contain many cytoplasmic granules with many Fe and Ca. In this region there is a short brush border and the dilated cell apices seem to discharge into the midgut lumen. In the posterior region of the midgut, the cells are cubic and contain few cytoplasmic granules that contain low amount of Ca and Fe. At the end of the midgut is a midgut-hindgut transitional region. Biochemical analyses showed the presence of a trypsin-like enzyme, amylase and lipase in all three midgut regions. These are discussed in relation to the feeding habits and evolution of the Hemiptera.