Effects of Growth Rate and Temperature on Metamorphosis inEurycea wilderae(Caudata, Plethodontidae, Hemidactyliinae, Spelerpini; Blue Ridge Two-lined Salamander)

The southeastern US has an incredibly diverse salamander fauna that contains ∼17% of the world's species. Furthermore, there is more variation in salamander life-cycle there than elsewhere—the diversity includes metamorphosing, paedomorphic, and directdeveloping species. The most diverse family in the world and in the southeastern US are the salamanders in the family Plethodontidae. I tested the hypothesis that variation in larvalgrowth history causes variation in metamorphic timing in Eurycea wilderae (Blue Ridge Two-lined Salamander), a member of 1 of the 3 lineages of plethodontid salamanders that metamorphose. Larval Blue Ridge Two-lined Salamanders were grown at 2 food levels and at 2 temperatures. Larvae that were fed more food grew faster, but effects on earlier metamorphic timing were minimal (3.84%, 13 d, P = 0.071). In contrast, larvae grown at a high temperature metamorphosed an average of 32.98% (55 d) earlier that those grown at a low temperature. In many amphibian species, the timing of metamorphosis is strongly affected by temperature and by variation in food availability. The weak response in timing of metamorphosis to variation in food is consistent with findings for other plethodontids and may be unique among amphibians.