Golgi body function and mucocomplex secretion in the Malpighian tubules of cercopoid larvae (Insecta: Homoptera)

Abstract

The proximal segments of the Malpighian tubules of cercopoid larvae are adapted for mucocomplex synthesis and secretion. In machaerotid larvae the proximal segment cells contain numerous Golgi bodies which synthesize mucocomplex fibrils. The fibrils are produced in the form of stacks, and they have a strict spatial and temporal relationship to each other. This static record of Golgi body activity can only be interpreted as the continual production of lamellae from transitional vesicles derived from RER at the forming face and the sequential accumulation of fibrils at the maturing face. Dense Golgi vesicles are formed by the condensing lamellae at the forming face, and these migrate around the lateral margins of the stacks and fuse with fibril-forming lamellae. Other cells in machaerotid Malpighian tubules contain numerous Golgi bodies which synthesize mucocomplex granules. The proximal segment cells of cercopid and aphrophorid larvae comprise very similar cells. The granules are formed in a similar manner to the fibrils and are also frequently in stacks although not so precisely arranged.