Spermatogenesis of the water strider, Gerris paludum (Heteroptera, Gerridae)

Abstract

Fine structural observations during spermatogenesis in Gerris paludum are described, including changes in mitochondria, acrosome, and microtubules. Early spermatid perinuclear ER cisternae and later stage membrane-bound ER cisternae seem to form a membranous sleeve at mid spermatid. G. paludum has an extremely long and complex acrosome. The acrosomal vesicle of the early spermatid is nearly spherical and 6.7 μm in diameter and the acrosome of the mature spermatozoon is 0.4 μm in diameter at the base and 0.16 μm at the tip. In mature bundled spermatozoa the acrosomes are arranged in a regular direction. The cytoplasm of the cyst cell contains a great number of modified microtubules with one to three long projections, all of which curve in the same direction. Microtubules along the interior rim of the cyst cell have one or no projections. This type of microtubule is evidently specific for the genus Gerris of the family Gerridae.