Pattern of ovarian activity in the Indian toad. Bufo melanostictus (Schn.)

Abstract

Oogenesis in the toad is of continuous type occurring throughout the year. The prefollicular cells divide mitotically to increase their number, to surround the developing follicles. The vitellogenesis begins from periphery and progresses towards the centre. The theca and granulosa layers in the mature follicles cannot be clearly differentiated. Binuclear oocytes are rarely found.The ovarian cycle of the toad can be broadly classified into prespawning (April-May), spawning (June-August) and postspawning-cum-preparatory period (September-March). The classification is based on the seasonal changes in the gonadosomatic index, diameter of the largest oocytes and ovarian histology. The breeding activity of the toad coincides with the rainy months of monsoon.