RESUMO
In a combined approach, endocrine and ultrasonic analyses were performed to assess reproduction of two syntopic populations of terrestrial Galápagos iguanas the Conolophus marthae (the Galápagos Pink Land Iguana) and C. subcristatus on the Volcán Wolf (Isabela Island). The ELISA methods (enzyme-linked immunosorbent assay) were used to measure plasma concentrations of progesterone (P4) and 17ß-estradiol (E2) from samples collected over the course of three different seasons: July 2010, June 2012-2014. As for C. subcristatus, the large number of females with eggs in 2012 and 2014 were associated with increased plasma P4 concentrations and the corresponding absence of females with eggs in July 2010 when concentrations of both hormones levels were basal indicating reproduction was still ongoing in June and had ended in July. In C. marthae, even though there was a positive relationship between egg-development stages and hormone concentrations, P4 concentrations were basal through the three years that samples were collected, with some females having a lesser number of eggs compared with C. subcristatus. In C. marthae P4 and E2 patterns did not allow for defining a specific breeding season.
Assuntos
Estradiol/fisiologia , Lagartos/sangue , Progesterona/sangue , Reprodução/fisiologia , Animais , Equador , Feminino , Lagartos/fisiologiaRESUMO
Carotenoids have received much attention from biologists because of their ecological and evolutionary implications in vertebrate biology. We sampled Galápagos land iguanas (Conolophus subcristatus) to investigate the types and levels of blood carotenoids and the possible factors affecting inter-population variation. Blood samples were collected from populations from three islands within the species natural range (Santa Cruz, Isabela, and Fernandina) and one translocated population (Venecia). Lutein and zeaxanthin were the predominant carotenoids found in the serum. In addition, two metabolically modified carotenoids (anhydrolutein and 3'-dehydrolutein) were also identified. Differences in the carotenoid types were not related to sex or locality. Instead, carotenoid concentration varied across the localities, it was higher in females, and it was positively correlated to an index of body condition. Our results suggest a possible sex-related physiological role of xanthophylls in land iguanas. The variation in the overall carotenoid concentration between populations seems to be related to the differences in local abundance and type of food within and between islands.