Fine structure of the Malpighian tubules in Gryllus campestris (Linnaeus, 1758) (Orthoptera, Gryllidae)


Abstract: The Malpighian tubules are responsible for excretion and osmoregulation in insects. The Malpighian system consists of tubules that are closed at the distal end and extend from the point of junction of the midgut and hindgut. This organ helps the water and electrolyte balance of the internal metabolism by filtration with absorption of water and soluble materials as mineral salts from the hemolymph. In this study, the histology of Malpighian tubules in Gryllus campestris (Orthoptera, Gryllidae) has been examined in detail by light microscopy, scanning electron microscopy, and transmission electron microscopy. The distal ends of the Malpighian tubules in G. campestris, which are long and wiggly in shape, extend freely into the body cavity. The other end is connected to the alimentary canal. In a cross-section of the tubules, it has been observed that the outer surface of the cells is covered by muscles and trachea. The lumen is lined with a single-layer epithelium. The nuclei (which are oval or spherical in shape), rough endoplasmic reticulum, mitochondria, and spherocrystals or mineral concretions are seen in the cells. Microvilli are found in the apical membrane. When the structure of the Malpighian tubules was compared with those of other species belonging to Orthoptera and other insect orders, similarities and differences were observed.

Keywords: Excretory system, Malpighian tubule, ultrastructure, electron microscope

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