Effects of Incubation Temperature and Water Potential on Growth and Thermoregulatory Behavior of Hatchling Cuban Rock Iguanas (Cyclura nubila)

To examine the effects of incubation temperature and moisture levels on embryonic development and posthatching growth and behavior, we incubated a total of 123 eggs collected from 18 wild female Cuban rock iguanas at 28.0, 29.5, or 31.0 C on wet (-150 kPa), moist (-550 kPa), or dry (-1100 kPa) substrates. Although there was no effect of incubation temperature or water availability on egg survival, larger females exhibited higher infertility and greater mortality of initially viable eggs, suggesting that reproductive senescence may occur in this long-lived species. Incubation temperature, although it had little influence on size at hatching, significantly affected several measures of growth, including changes in body length, mass, and head dimensions. In general, hatchlings from higher incubation temperatures grew faster during their first year. However, by 16 months of age, growth rates no longer varied among hatchlings incubated at different temperatures. Incubation temperature had no detectable effect on thermal selection by hatchlings at 14 to 16 months of age, as there was no tendency for hatchlings incubated at higher temperatures to preferentially select higher basking temperatures. Moisture levels during incubation did not significantly affect size, growth, or thermoregulatory behavior of hatchlings. These results have important implications for understanding how environmental conditions experienced during embryonic development may affect future fitness