Abstract

The ecological trade-off between foraging gains and predation risk shapes the ecology of many taxa, including larval amphibians and fishes. Is this ecological trade-off reflected at the population level as a negative genetic correlation between traits that contribute to growth and survival? We addressed this question for a single population of Green Frog tadpoles (Rana clamitans) by estimating heritabilities and correlations of traits that mediate the trade-off. Burst speed, growth rate, and size varied among sires and were significantly heritable, but swimming activity in the presence and absence of predator odors was not. Differences among traits in heritability generally accorded with differences in genetic coefficients of variation, with the exception of activity. Growth rate was not correlated with any measure of predator avoidance or escape ability. Likewise, predator escape ability (burst speed) was not correlated with predator avoidance ability (activity and its plasticity). Our results indicate that trait correlations observed among species may not be mirrored at the intraspecific level in the form of genetic correlations within a population.