CICLO ANUAL DA GAMETOGÊNESE DE Brachidontes darwinianus darwinianus (ORBIGNY, 1846) - BIVALVIA MYTILYDAE

Abstract

SUMMARY

The anual cycle of gametogenesis of B. darwinianus darwinianus was studied in relation to the sexual cycle of other Mytilidae, mainly of M. perna, a tropical mussel.

During the years 1975 and 1976, monthly 20 males and 20 females were collected on the beachat Ubatuba, Coast of Sao Paulo, Brazil.

Sections of 5 µm were made of mantle tissues and visceral mass, fixed in Bouin's fluid, and stained with Ehrlich's haematoxylin and eosin.

The classification of CHIPPERFIELD (1953), LUBET (1959), and LUNETTA (1969) was adopted for identification of different gametogenesis stages. Only the period of reproduction was determined. The cytochemical techniques used by these authors, were not employed.

The sexual cycle of B. darwinianus darwinianus is practically continuous and there is one reproduction peak in autumn (April, May and June) when there is a synchronism of gametogenesis in both sexes.

There is no very marked period of sexual quiescence. The state of partial or total elimination of gametes may be related with the lower autumn temperature (22ºC).