EFFECTS OF LARVAL GROWTH HISTORY ON METAMORPHOSIS IN A STREAM-DWELLING SALAMANDER (DESMOGNATHUS-OCHROPHAEUS)

Length of the larval period is a component of fitness for most amphibi ans. Some theoretical models predict that length of the larval period is a function of growth history; however, these models have been teste d using species that inhabit temporary, productive habitats. I tested the hypothesis that length of the larval period in permanent, low prod uctivity habitats is also a function of growth history. I exposed larv ae of the stream-dwelling salamander Desmognathus ochrophaeus to diffe rent temperature, food, and water change regimes. Profile analysis of growth demonstrated significant effects of food and temperature on lar val 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 r egimes affecting growth more at high temperature. Larvae at high tempe ratures metamorphosed earlier. Larvae at low temperature metamorphosed later at a larger size. High food regimes increased the metamorphic s ize of larvae at both temperatures. However, variation in food regimes did not affect length of the larval period.