Ultrastructure and morphogenesis of the abdominal integumental gland of Schistocerca gregaria forsk. (Orthoptera: Acrididae)

Abstract

The objective of this research is to describe the morphogenesis and the structures of the abdominal glands in the late 4th and 5th instar nymphs of Schistocerca gregaria. The glands are composed of 4 cells called secretory, ciliary, canal and enveloping cells, according to their morphology and functions. The secretion, stored in the secretory cell in the form of electron-dense granules, is discharged during ecdysis through a cuticular duct, after the ciliary cell has unplugged its opening. The discharge of the secretion is facilitated by the pressure exerted by the hemolymph at ecdysis and by the spreading of the integumental folds. This secretion appears to be involved in the deposition of the cement layer of the cuticle. After ecdysis, the ciliary and enveloping cells die, and their remains are incorporated by the surrounding epidermal cells. The secretory cell begins to synthesize new secretory granules and remains joined with the canal cell, forming a 2-cell secretory unit, which remains functional throughout imaginal life.