Environmental Influences on Plasticity in Growth and Development of the Tallulah Salamander, Desmognathus perlapsus

In amphibians having complex life cycles, growth trajectories incorporate three major developmental switches—hatching, metamorphosis, and maturation—that regulate the transition from one stage to the next. The switches are targets for environmental cues that may generate phenotypic divergence in developmental pathways among populations of a species. In the current study, we have conducted an analysis of phenotypic plasticity in growth and developmental rates in populations of the plethodontid salamander Desmognathus perlapsus in the southern Blue Ridge/Cowee Mountains of North Carolina and Georgia, USA. Populations in this area occur in two habitats, rock face and woodland. The larval phase of D. perlapsus is relatively fixed, with limited plasticity in body size and age at metamorphosis. Following metamorphosis, salamanders in woodlands grow faster and attain larger sizes than those on rock faces. There is evidence of genetic differentiation in maturation rate among isolated rock-face populations. However, there is no documented evidence of genetic differences between adjacent woodland and rock-face populations. Temperature, food availability, and predatory threats are three environmental variables that have been implicated in the expression of plasticity in this species.