The sperm glycocalyx of Pezotettix giornai (Rossi) (Insecta : Orthoptera) after quick-freeze, deep-etching

Mature spermatozoa of the catantopid orthopteran Pezotettix giornai are cha racterized by an elaborate external glycocalyx. This coating is removed dur ing storage in spermatheca allowing preparation of sperm to their interacti on with female gametes. We have studied this membrane coating in mature spe rm by both conventional transmission electron microscopy and quick-freeze, deep-etching. The ultrastructural studies allowed visualization of three di fferent domains in glycocalyx of testicular and deferent duct spermatozoa a nd only two in sperm cell isolated from seminal vesicles. These observation s thus demonstrate that a remodeling of the male germ cell starts already d uring their storage in the seminal vesicle and is completed in the female g enital tract. In this paper a three-dimensional (3D) model of sperm externa l coating is presented and discussed.