Effects of Larval Growth History on Metamorphosis in a Stream-Dwelling Salamander (Desmognathus ochrophaeus)

Abstract

Length of the larval period is a component of fitness for most amphibians. Some theoretical models predict that length of the larval period is a function of growth history; however, these models have been tested using species that inhabit temporary, productive habitats. I tested the hypothesis that length of the larval period in permanent, low productivity habitats is also a function of growth history. I exposed larvae of the stream-dwelling salamander Desmognathus ochrophaeus to different temperature, food, and water change regimes. Profile analysis of growth demonstrated significant effects of food and temperature on larval growth rates. Larvae that experienced high temperature and/or high food regimes grew faster than larvae on low temperature and low food regimes. Food and temperature interacted in a complex way, with food regimes affecting growth more at high temperature. Larvae at high temperatures metamorphosed earlier. Larvae at low temperature metamorphosed later at a larger size. High food regimes increased the metamorphic size of larvae at both temperatures. However, variation in food regimes did not affect length of the larval period.