Water relations of the eggs of anolis-auratus and anolis-limifrons

Eggs of Anolis auratus and Anolis limifrons were incubated on soil substrates differing in matric potential of soil water. Eggs of both species hatched after a mean incubation time of 44 d on soils with matric potentials of -1.48 MPa or greater. On soils with water potentials of -2.13 and -2.74 MPa, eggs gained in mass initially but eventually desiccated. The rate of water storage was greater for A. auratus eggs than for A. limifrons eggs on all treatments. Rates of water loss by transpiration from the surface of eggs exposed to the atmosphere was a linear function of egg mass for both species, with A. auratus eggs losing less water per unit time than A. limifrons eggs. Differences in water flux were correlated with eggshell morphology. Eggshells of A. auratus were thicker, had a greater density of fibrils, and had a thicker matrix of calcium carbonate than eggshells of A. limifrons. Thus, the eggs of A. auratus seem to be adapted to the dryness of their grassland habitat and the eggs of A. limifrons seem to be adapted to the more equitable and humid conditions of their rain forest habitat.