Reproductive activity of bombina pachypus from southern Italy

Abstract

Seasonal changes in gonadal morphology, secondary sexual characters, and plasma sex steroids were studied in male and female Bombina pachypus from southern Italy. In this species, frogs are active and breed from May to September. During the long breeding season, sperm were always present in the testes. However, the testes did not always exhibit all stages of spermatogene-sis. In July, spermatogenesis did not exceed the stage of sperma-tocyte I, whereas in August it included all stages. It is possible that males use sperm originating from the preceding fall for the earliest spring matings. Throughout the breeding season, females showed many follicles in advanced or complete vitellogenesis and many atretic vitellogenic follicles. Postovulatory follicles, if any, were rare. Females laid few eggs at each oviposition. Concerning male sex steroids, testosterone was at comparable levels from May to September, and it markedly decreased in October. In females, wide variations in plasma estradiol and progesterone levels were observed only in individuals with postovulatory follicles. Emphasis is given to the prolonged and opportunistic reproductive activity of this species. © 1998 Taylor & Francis Group, LLC.