Spermiogenesis in Aedes aegypti (L.)

Abstract

1. Spermiogenesis was studied in living and fixed cells from pupal and young adult testes of Aedes aegyvti (L.).
2. Fusion of thickened, rod-like mitochondria in cytokinesis of the second meiotic division results in nebenkern formation. Very early in spermiogenesis an axial filament makes its appearance, extending from the nuclear membrane to bisect the nebenkern. In the course of differentiation the axial filament and nebenkern extend distally from the nucleus to result in flagellum formation.
3. Condensation and elongation describe nuclear differentiation. Midway in spermiogenesis two juxtanuclear bodies of uncertain origin become strikingly apparent in the head piece but are lost to view in final maturation.
4. No dictyosomes, acroblast or acrosome were observed. Further, germ cells were periodic acid-Schiff negative. Thus no acrosome develops in spermiogenesis.
5. The fully differentiated spermatozoon is a thread-like cell consisting of (a) a needle-like nucleus and (b) a flagellum of two mitochondrial threads and a central axial filament.