Comparative study of the structure of the reproductive system of dwarfish males of Glyphina betulae (Linnaeus, 1758) and Anoecia ( Anoecia) corni (Fabricius, 1775) (Hemiptera, Aphididae)

Abstract

The morphology and ultrastructure of the male reproductive system of dwarfish males of the monoecious aphid species Glyphina betulae (subfamily Thelaxinae) and the heteroecious species Anoecia ( Anoecia) corni (subfamily Anoeciinae) are described. The testicular follicle of these species has the form of a single sac, the proximal parts of the vasa deferentia are slightly ( G. betulae) or strongly ( A. ( A.) corni) expanded, the accessory glands are sack-shaped, and in G. betulae asymmetric and strongly elongated, whereas the ejaculatory duct is short. In both species only mature spermatozoa have been found within the testicular follicles, i.e. the consecutive stages of spermatogenesis have not been observed in adult males. Our studies also show that the testicular follicle, vasa deferentia, accessory glands and ejaculatory duct are histologically very simple. They are composed of more-or-less flattened epithelium of a secretory type, and thin muscle fibres. The epithelial cells are rich in rough endoplasmic reticulum, mitochondria and small vacuoles. The vasa deferentia, especially in G. betulae, are filled with an electron-dense secretion which, as was shown by histochemical staining, contains proteins and polysaccharides. We suggest that the maximum secretory activity of these epithelial cells occurs, as does spermatogenesis, during larval stages, so that the short living adult males are immediately ready for copulation as in other aphids with normal-sized males.