Gonad Structure and Reproductive Cycle of Bokermannohyla nanuzae (Anura, Hylidae) in Southeastern Brazil

Abstract. We studied gametogenesis and reproduction of Bokermannohyla nanuzae at an Atlantic Forest site in southeastern Brazil from August 2011 to July 2012. We observed frogs with mature germ cells almost year-round, indicating continuous gametogenesis. However, advanced gonad maturation occurred in wet months, when we observed females spawning and spermiated males. We observed calling males with mature testes in all bimesters but spermiated males only from October to January. This pattern of continuous calling may be associated with male strategies to be selected by females within male choruses. We did not observe males with testes at rest or females with ovaries at rest, and throughout the year we observed spermatogenic cells in all developmental stages in males as well as vitellogenic oocytes in different maturation stages and several post-ovulatory follicles in females, indicating that both males and females may be ready to respond to a specific environmental cue to release their gametes or even be able to breed multiple times throughout the year. This promptness to breed may be adaptive as it allows frogs to reach mature stages faster when environmental conditions are suitable for breeding and even breed more than once per breeding season.