Developmental plasticity in Painted Turtles, Chrysemys picta


Gary C. Packard, Department of Biology, Colorado State University, Fort Collins, CO 80523–1878, USA.


1. The contents of newly constructed nests of Painted Turtles, Chrysemys picta, were manipulated by reciprocal transplant, so that each of several nests received a complement of eggs from each of several females. The eggs were recovered from nests after 8 weeks and allowed to complete incubation under standard conditions in the laboratory.

2. Live mass, dry mass and water content of carcasses, and dry mass of unused yolk, varied significantly among hatchlings from eggs that incubated in different nests. Indeed, hatchlings from different nests sometimes differed as much in size or physiological condition as animals from different clutches.

3. Stepwise linear regression indicated that size of hatchlings and water content of their carcasses were positively correlated with water exchanges by eggs whereas mass of the unused yolk was negatively correlated with water exchanges. Although the statistical procedure is only correlative, the findings accord well with results of laboratory studies documenting a relationship between uptake of water by eggs, metabolism and growth by embryos, and size and condition of hatchlings.

4. Developmental plasticity, coupled with variation in the physical environment within and among nests, probably accounts (minimally) for 19% of the variation in live mass of hatchlings in the field; 24% of the variation in dry mass of carcasses; 11% of the variation in hydration of carcasses; and 26% of the variation in dry mass of unused yolk. Such variation may impact survival by neonatal animals, and needs to be addressed explicitly by models for the evolution of life history in Painted Turtles.