EFFECT OF PREDATORY LARVAL DESMOGNATHUS-QUADRAMACULATUS ON GROWTH, SURVIVAL, AND METAMORPHOSIS OF LARVAL EURYCEA-WILDERAE

I examined whether predation affects larval life-history parameters of the streamdwelling salamander Eurycea wilderae. In cages placed in a North Carolina stream, I exposed groups of 10 larval E. wilderae to 0, 1, or 3 predatory larval Desmognathus quadramaculatus. Growth and sur vival of E. wilderae were recorded every two months from August 1991 t o June 1992, and metamorphic stage was recorded for all surviving prey at the end of the experiment. Survival rates did not differ among tre atments during any of the two-month intervals, but larvae in zero-pred ator treatments experienced higher survival over the duration of the e xperiment. Risk of predation caused significant variation in growth ra tes during the last four months. Larvae in three-predator treatments g rew the fastest from February to April but grew more slowly than the z ero-predator and one-predator treatments from April to June. Given tha t many larval amphibians utilize temporary, high productivity habitats , current models predict that variation in growth rate and/or mortalit y risk should result in variation in metamorphic timing and/or size. H owever, larval E. wilderae that experienced different growth rates and predation risk metamorphosed at the same time. Because southern Appal achian mountain streams are relatively permanent and have low producti vity, there may be little or no advantage of maintaining plasticity in time or size at metamorphosis.