Quantitative analysis of the ovarian cycle of the lizard Lepidodactylus lugubris

Abstract

Patterns of ovarian follicular growth and atresia, as well as changes in number of oogonia, primary oocytes, and primordial follicles, were studied in the gecko Lepidodactylus lugubris. Sizes of larger, growing follicles increased at the stage in the ovarian cycle when yolking of the largest follicle occurred. Atretic follicles were replaced by new growing follicles recruited into the follicular size hierarchy. The single germinal bed in each ovary, containing oogonia, oocytes, and primordial follicles, was most active during the vitellogenic period. The two ovaries of this species each ovulate one egg simultaneously, and each contains only five growing follicles, about 17% of which are atretic. In contrast, each ovary of other lizard species that ovulate two eggs simultaneously contains two germinal beds and a relatively high number of growing follicles. Extensive follicular atresia (>50%) reduces the number of ovulations to one in these species.