[Spermatogenesis in the yellow-bellied toad (Bombina variegata variegata L.) during the seasonal activity period and in correlation with the mating call activity (Discoglossidae, Anura)].

The spermatogenic tissue in the yellow-bellied toad Bombina variegata has certain properties not shared by other Central European anurans. Sertoli cells are lacking; the sperms are not bundled within the seminiferous tubules, but rather they form and mature in a connective-tissue follicle that is cellular in nature. Spermatogenesis is not a continuous process, at either the spermatocyte or the spermatozoa formation stage. Rather, there are periods of stagnation and of proliferation, which can be correlated with the periods during which the male toads produce mating calls and with the pauses between the calling periods. The crucial participation of hormonal factors in these processes is discussed.