Reproductive activity and plasma androgen concentrations in the male ofRana dalmatina

Abstract

Abstract Reproductive activity (spermatogenesis, testis and fat‐body weight, thumpad) is related to environmental factors and plasma androgen levels in the male of Rana dalmatina. The population studied, living at 1000 m a.s.l., showed a markedly discontinuous spermatogenetic cycle. From November to February, spermatogenesis stopped completely. Spermiation occurred from late February to late March. In May, there was recovery of spermatogenesis. The mating season and ovipositions took place from the end of February to late March or early April, when environmental temperatures increase and the pool where this species reproduces thaws. Significant seasonal variations were observed in the testis and fat‐body weight, thumpad epithelium, and plasma testosterone but not in plasma androstenedione. Plasma testosterone peaked in February, two months after the maximum development of nuptial callosity; however, there was a positive correlation between these two characters, which was not observed, instead, between nup...