Histochemische Untersuchungen über Funktion und Verbleib eu- und oligopyrener Spermien von Viviparus contectus (Millet 1813), (Gastropoda, Prosobranchia)

Abstract

1. Histochemical examinations of paraffin sections and smear preparations of Viviparus contectus (Millet 1813) were made in an effort to determine the function and ultimate fate of the oligopyrene sperm. 2. A progressive disappearance of the eupyrene and oligopyrene sperm from the female reproductive tract after copulation had terminated was not observed because V. contectus, in its natural habitat, normally attains a high population density with the occurrence of frequent copulations so that the females receive an abundance of sperm before the end of each mating season. As a result a surplus of sperm was found in the reproductive tracts of all of the females which were examined throughout the entire year. 3. Spermatocytes and spermatids, in addition to mature eupyrene and oligopyrene sperm, are deposited in the female's reproductive tract during copulation. 4. Pieces of eupyrene sperm heads and what appeared to be the tail pieces of both types of sperm were ingested by the epithelial cells which line the vagina and brood pouch. 5. The ingestion of sperm parts by the epithelial cells of parts of the female reproductive tract throughout the year probably provides the female with a continuous source of nutrition. 6. Intact oligopyrene sperm were not ingested. Histochemical examinations of smear preparations which were made of the contents of the female reproductive tract after copulation had terminated revealed that the oligopyrene sperm disintegrated in the brood pouch and seminal receptacle. 7. The middle piece sheath of the oligopyrene sperm contains glucose granules. The chemical nature of these granules was determined with the Okamoto (1948) histochemical method for the identification of glucose. 8. The disintegration of the oligopyrene sperm, and some of the eupyrene sperm, after copulation released glucose and polysaccharides into the brood pouch and seminal receptacle. It is possible that these processes provide nutrition for the eupyrene sperm as they move toward the seminal receptacle, oviduct and albuminous gland where they are stored and later fertilize eggs. 9. It is possible that the disintegrated and ingested sperm which were found in the albuminous gland are converted into yolk by the glandular cells of this gland. 10 What appeared to be copulation-like behavior occurred between males during the Spring and Summer months. This behavior has been termed pseudocopulation because subsequent examination of the mantel cavity of the male which played the role of the female during a copulation between two males revealed that no sperm transfer had taken place. This behaviour probably results from an unknown sex stimulating substance which is released by the female. In the vicinity of males it stimulates the males to copulate with a female or with each other if the males happen to be nearer to each other than the female. No pseudocopulations were observed in those aquaria which contained only males. © 1968 Springer-Verlag.