Reproductive pattern and sex hormones of Calotes emma Gray 1845 andCalotes versicolor Daudin 1802 (Squamata; Agamidae)

Abstract

We monitored testicular and ovarian morphologies, seminiferous tubules, the sexual segments of the kidneys (SSK), follicular histologies, and male testosterone and female estradiol to define the reproductive pattern of Calotes emma and Calotes versicolor. Samples were collected monthly at Sakaerat Environmental Research Station in Thailand for 1 year. Testicular hypertrophies occurred at a time characteristic for each species, with their time course corresponding well to both active spermatogenesis and the hypertrophied SSK. Gravid females were also found at a time characteristic for each species. In active reproductive females, oviductal eggs were concomitantly encountered with ovarian vitellogenic follicles. The previtellogenic and vitellogenic follicles corresponded well to granulosa layer alterations. The distinct large pyriform cells were present in the granulosa layer of previtellogenic follicles but disappeared from the vitellogenic follicles. Male testosterone levels rose during testicular and SSK hypertrophies, and female estradiol levels increased during active reproductive stages of late vitellogenic follicles and gestation. We suggest that the reproductive patterns of C. emma and C. versicolor fall into the same reproductive pattern of annual continual reproduction, but that the time courses of such events are different in the 2 Calotes, and even in individuals of the same Calotes population.

Sexual segment of the kidney of the lizard, Eutropis carinata: A light microscopic and ultrastructural seasonal study

“…The SSK undergoes a seasonal cycle that has been confirmed in numerous studies on, both lizards and snakes, and is correlated to seasonal testicular activity and androgen synthesis (Aldridge, 1993, 2002; Aldridge & Brown, 1995; Arvy, 1969; Bishop, 1959; Burtner, Floyd, & Longley, 1965; Forbes, 1941; Fox, 1965; Johnson et al, 1982; Meesook, Artchawakom, Aowphol, & Tumkiratiwong, 2016; Norris, 2013; Kehl, 1944; Krohmer, 2004; Krohmer & Aldridge, 1985; Krohmer, Grassman, & Crews, 1987; Rojas, Barros, & Almeida Santos, 2013; Shivanandappa & Sarkar, 1979; Sarkar & Shivanandappa, 1989; Van Wyk, 1995; Volsøe, 1944; Weil & Aldridge, 1981). The SSK is hypertrophied when plasma androgen levels are elevated.…”