Abstract

The reproductive cycle of Pleurodema thaul is described. Males were analyzed according to their spermatogenic stage using histological sections of their testes. For females we used the size and pigmentation of the ovarian follicles. The results show a partially continuous reproductive cycle. Males produce sperm during almost all the year. Spermatogenesis is initiated in summer (February-March), when the seminiferous tubules contain abundant undifferentiated spermatozoids, which are transformed to spermatozoa as fall advances (May-June). The first spermatozoa appeared in late May, and spermatogenesis increased from July to September, sometimes to November. Females present bimodal vitellogenic activity. The first vitellogenic phase is initiated in late February with a progressive maturation of the oocytes, reaching the post-vitellogenic stage between June and August. The breeding period is established during these months and continues until December. In September, some females can begin the vitellogenesis, with a second stage that ends in middle December, when the oocytes that were not spawned, pass massively to the atresic stage. The fat bodies show a synchronic increase with the gametogenic activity in both sexes, that coincide with the greater reproductive activity. Fat bodies are likely to be used as energetic reserve for the vitellogenic activity.