Malpighian tubules of pharate adult during pupal-adult development in flesh fly, Sarcophaga ruficornis Fab. (Diptera: Sarcophagidae)

The Malpighian tubules of pharate adult of Sarcophaga ruficornis lacks the characteristics of transporting epithelia with extremely thick basal lamina and absence of basal membrane infoldings. There is heavy vacuolation in the region of basal infoldings. The mitochondria, very often filamentous in nature, are abundantly found in the tubule cells, lying parallel towards the apical region and in the process of being inserted into luminal microvilli. All the luminal microvilli do not contain mitochondria; some of them are devoid of these structures. The central cytoplasm contains a prominent nucleus, a high density of mitochondria, lipid droplets, spherocrystals and multivesicular bodies. Outside the basal lamina, are found several tracheoles. The study supports the standing gradient hypothesis for fluid transport by Malpighian tubules.