Male reproductive cycle of the water frog Rana epeirotica in northwestern Greece

The reproductive cycle of male Rana epeirotica was studied with emphasis on spermatogenetic activity and changes in the weights of testis, fat body an d liver. The spermatogenesis of Rana epeirotica is of the potentially conti nuous type. Significant seasonal variations were observed in testis, fat bo dy and liver weight. The seasonal variation of testis weight showed a good agreement with the spermatogenetic cycle. The reduction of fat body weight during the pre-hibernating period was attributed to mobilizing of lipids to other body parts or to transformation into other metabolites. The signific ant decrease of liver weight in the dormant period indicates that this frog consumes mainly glycogen during wintering. The greatest decrease of fat bo dy and liver weight in May results from the intensive activities related to reproduction and maintenance.