The Effects of Incubation Temperature On Hatching Success, Embryonic Use of Energy and Hatchling Morphology in the Stripe-tailed Ratsnake Elaphe taeniura

We incubated eggs of Elaphe taeniura at 22, 24, 27, 30 and 32°C to examine the effects of incubation temperature on hatching success, embryonic use of energy and hatchling morphology. Incubation temperature affected incubation length and most hatchling traits examined in this study. Incubation length increased nonlinearly as temperature decreased, with the mean incubation length being 101.7 d at 22°C, 86.0 d at 24°C, 66.3 d at 27°C, 53.9 d at 30°C, and 50.5 d at 32°C. Hatching successes were lower at the two extreme temperatures (41.2% at 32°C, and 50.0% at 22°C) than at the other three moderate temperatures (78.1–79.3%). Hatchlings from the extreme high incubation temperature (32°C) were smaller in body size and wet body mass. High incubation temperatures resulted in production of less developed hatchlings that characteristically had less developed carcasses but contained more unutilized yolks. The proportion of energy transferred from the egg contents to the hatchling was 71.1% at 22°C, 80.2% at 24°C, 81.5% at 27°C, 82.6% at 30°C and 83.9% at 32°C. Taking the lowest hatching success at 32°C and the substantially prolonged incubation lengths at 22°C into account, we conclude that these temperatures are not suitable for embryonic development in E. taeniura. Our data confirm the prediction that there are some thresholds over which incubation temperatures can affect hatching success, embryonic use of energy and hatchling morphology.