Meeting Abstract
Turtle embryos may experience considerable fluctuation in temperature during development, but laboratory studies frequently incubate eggs under single constant temperatures for the entirety of development. When incubated under single constant temperatures, increased temperatures leads to earlier hatching and smaller body sizes. In this study, I incubated snapping turtle eggs at a constant 29°C for a period of 40 days, then divided the eggs among three different constant temperatures (27, 29, and 31°C) for the completion of incubation. There was no difference among the different groups in embryo size or amounts of yolk at Day 40. However, by Day 50 embryos were larger, and the yolk smaller in eggs incubated at 27°C than in the 29°C or the 31°C group. Contrary to previous observations, eggs that were incubated at 27°C hatched sooner than those at the two higher temperatures. Moreover, hatchling size differed significantly among the three groups, with 27°C yielding the largest hatchlings and 29°C yielding the smallest hatchlings. My findings suggest that variation in temperature at different intervals during embryonic development may induce changes in growth rate that would not be predicted if a simple unidirectional association between growth and temperature is assumed.
