INTERACTIONS BETWEEN LARVAL SALAMANDERS - A CASE OF COMPETITIVE EQUALITY

Larvae of Siren intermedia and Notophthalmus viridescens possess markedly different morphologies and life histories, but feed on similar prey. Both intraspecific and interspecific competition caused a decline in survival of Notophthalmus, but had no detectable effect on body size or length of larval period. Negative density-dependent mortality may regulate Notophthalmus populations in the larval stage of their complex life cycle. Intraspecific competition caused a decline in both the survival and growth of larval Siren, but interspecific competition caused only growth to decline. Decreased growth rates may increase the vulnerability of larval Siren to desiccation and to predation. There was no evidence to reject the null hypothesis that larvae of these two species are equal competitors at the densities employed. Larval Siren and larval Notophthalmus appear to compete as equals. -from Authors