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

Abstract

The reproductive cycle of female Rana epeirotica in Lake Ioannina, northwestern Greece was studied from 1998 to 1999. Young females reached sexual maturity at a weight of 26.3 g and a length of 67.2 mm. The annual cyclic changes in weight and histological composition of the ovaries showed that R. epeirotica has a single reproductive period each year. Weight changes of the oviducts followed those shown by the ovaries. A continuous change in the percentage and diameter size of the ovarian follicles through the annual cycle was found. Clutch size ranged from 600 to 2900 ova of 1.3 to 1.6 mm egg diameter. Ovarian weight, clutch size and ovum size were positively correlated to body weight. The weigth of fat body and liver had a peak in August and November respectively and they both were reduced considerably during hibernation.