Ultrastructure et chimie de la secretion des glandes tergales du male de Blattella Germanica (L.) (Dictyoptera : Blattellidae)

Abstract

In Blattella germanica, as in many other cockroaches, the tergal glands exist only in the adult male, and are involved in courtship behavior. These glands are found on segments 7 and 8, which are markedly modified. They occupy a transverse depression divided into two by a central ridge. The two glands go deeply under tergites 7 and 8, and have a thick glandular epithelium. The depressions serve as reservoirs for the secretion. The central pillars dividing the depressions possess numerous setae that are both mechano- and chemoreceptors. The tergal glands have only 3 basic types of cells: (1) epidermal cells that secrete the tergite cuticle and the cuticular lining of the reservoir; (2) associated cells filled with microtubules; (3) large gland cells (type 3) with a cuticular duct (secreted by the canal cells) that connects the glandular cells with the outer cuticle. There are 2 subtypes in the type 3 cells: (G1) the cells filled with dense myéloïd bodies, probably constituting the glycoproteinic part of the secretion; (G2) the cell is filled with electronluscent vacuoles. These cells are 3-times more numerous than the G1 cells, and probably secrete the volatile components (free fatty acids, para-hydroxy benzylic alcohol, O-hydroxy benzylic alcohol, di- and tri-methyl naphthalene and benzothiazole. Detailed structure and functional interpretation are discussed.