Corticosterone Plasma Levels of Embryo and Hatchling Broad-Snouted Caimans (Caiman latirostris) Incubated at Different Temperatures

Abstract

Abstract The temperature-sensitive period is the time during development during which sex determination occurs in vertebrates that undergo temperature-dependent sex determination, such as in caimans. The interplay among temperature and steroid hormones is also known, and it has been suggested that stress hormones (corticosterone) might influence sex ratios in some reptiles. To explore this, we measured the levels of corticosterone in Caiman latirostris to determine if incubation temperature (31°C, 33°C, and 34°C) affects plasma corticosterone levels. Differences among nests were observed in plasma corticosterone. However, hormone levels showed no significant differences between sexes or incubation temperatures in Caiman latirostris embryos or hatchlings. Corticosterone levels were 0.01–2.2 ng/ mL in embryos incubated at 31°C (100% of females), 0.01–4.65 ng/mL in those incubated at 33°C (100% of males), and 0.01–6.31 ng/mL in embryos incubated at 34°C (100% of males). Corticosterone levels were higher in h...