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Ovarian changes during the reproductive cycle of the Tupinambis merianae lizard raised in a temperate environment

2007; Asociación Herpetológica Argentina; Volume: 21; Issue: 1 Linguagem: Inglês

1852-5768

Mario E. Manes, Teresa Noriega, Fernando Campos Casal, Silvana A. Apichela,

Wildlife Ecology and Conservation

temperate environment consists of three gonadal phases: previtellogenic, vitellogenic and postovulatory or luteal phases. During the previtellogenic phase, which takes great part of the summer, autumn and winter, the ovaries are small, weigh less than 4 g, and contain only nonvitellogenic follicles, which develop slowly from germinal beds, until they are almost 5 mm diameter. Due to an asynchronous gonadal maturation in both sexes, matings occur when ovaries are still previtellogenic. Then comes a short and intense vitellogenesis, during which follicles grow steadily increasing around 6 times their diameter (close to 30 mm), while the total ovarian mass reaches almost 400 g. The process culminates between the 15th and 20th day, with a widespread ovulation and a subsequent oviposition. As a consequence, postovulatory ovaries appear reduced to 5 g approximately, with a surface almost entirely covered with follicular scars, which soon developed luteal bodies. Blockade of the ovarian cycle, with a massive previtellogenic follicular atresia, as a result of females isolation leads to conclude on the existence of sexual stimuli promoting vitellogenesis.