Different incubation temperatures result in differences in mass in female red-eared slider turtle hatchlings

The Charnov-Bull model states that environmentally determined sex will prevail in patchy environments where males may fare best in one patch type, whereas females may fare well in a different patch type. To investigate whether or not potential differences manifest early in the life of a turtle with temperature-dependent sex determination, I assessed mass, carapace width and length, and plastron length of hatchlings from three different incubation temperature regimes. Differences in incubation temperature affected mass in turtles of the same sex; the difference appears to support a sex-based rationale for the phenotype. The results bear out an assumption of Charnov-Bull that neonates of the same sex from different temperatures may manifest different attributes (i.e., mass) that could affect their relative fitness.