Seasonal Variation of Gonadal Development, Sexual Steroids, and Lipid Reserves in a Population of the Lizard Psammodromus algirus

• Published in: Journal of herpetology 1994-06, Vol.28 (2), p.199-205
• Main Authors: Díaz, José A., Alonso-Gómez, Angel L., Delgado, María J.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Breeding seasons; Fat body; Follicles; Fundamental and applied biological sciences. Psychology; Lipids; Liver; Lizards; Mating behavior; Non mammalian vertebrate reproduction; Physiology and Biochemistry; Psammodromus algirus; Steroids; Testes; Testosterone; Vertebrates: reproduction
• ISSN: 0022-1511; 1937-2418
• DOI: 10.2307/1564621

We studied the seasonal variations of reproductive characteristics in a wild population of the lacertid lizard Psammodromus algirus by measuring gonadal weight, germinal epithelium height, sexual steroids (testosterone, estradiol, and progesterone), and lipid reserves (in fat bodies and liver) in three phases of the reproductive cycle: early breeding (late April), late breeding (mid-June), and post-breeding season (late July). In males, testis size, germinal epithelium, and testosterone plasma levels were high in the breeding season and decreased dramatically in July. However, spermatogenesis (maximum in June) was slightly delayed with respect to testosterone secretion (peak in April), suggesting that a previous increase in testosterone levels could be necessary to stimulate the initial stages of spermatogenesis. Larger testes and higher testosterone levels were found in larger and more brightly colored males, known to overlap with more females and court them more frequently than their smaller conspecifics. In females, the ovary was previtellogenic in early spring, and showed a rapid growth by mid-June, oviposition occurring in early summer. The increase in 17 β-estradiol levels observed between April and June was coincident with the maturation of previtellogenic follicles. In both sexes fat body cycles were inversely correlated with gonadal cycles. By the end of the breeding season there was a reactivation of hepatic lipogenesis that was coincident with a significant decrease in activity levels.