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Abstract

The present study aims to investigate the morphological, histological and cytological changes among the four midgut regions of Spilostethus pandurus adult. The adults were dissected to examine the four midgut regions. The cellular structure of the midgut was clarified by means of light and electron microscopy. The midgut consists of a single layered epithelium of two cell types. Most cells were binucleated and this may be due to active digestive properties. The midgut region has no peritrophic membrane but has internally a perimicrovillar membrane. The electron dense glycocalyx layer separates the plasma membrane from an outer or perimicrovillar membrane which is produced continuously into the midgut lumen, possibly also from secretory lysosome-like vesicles. The lysosomes and large amounts of rough endoplasmic reticulum indicate that the second, third and fourth midgut regions play a role in food digestion. The lipid in the second midgut region suggests that this region plays only a minor role in lipid absorption and energy storage. The distribution of different cell types in S. pandurus midgut could be correlated with the physiology of digestion and absorption.