Behavioral syndrome persists over metamorphosis in a pond-breeding amphibian

Abstract

Abstract: In recent years, behavioral ecology has shifted from assuming animal behavior is infinitely plastic and situation specific to recognizing that behavior can be limited in its plasticity and correlated across different ecological situations. At the center of this new framework are behavioral syndromes or consistent individual differences in behavioral tendencies. Over the past decade, numerous studies have identified the evolutionary mechanisms and ecological implications of behavioral syndromes. However, the persistence of behavioral syndromes over ontogeny remains an open question. Species with complex life cycles present an interesting system in which to test the persistence of behavioral syndromes, because such life histories are thought to evolve when correlations between life stages are costly. In this study, we tested the hypothesis that behavioral tendencies of species with complex life histories are consistent within a life stage (before or after metamorphosis) but not between life stages. We experimentally assayed the activity, boldness, and exploration of spotted salamanders (Ambystoma maculatum) before and after metamorphosis. We found most behaviors to be at least moderately repeatable. Additionally, there was support for a behavioral syndrome within the larval stage as well as between larval behaviors and juvenile boldness. Our results reject the adaptive decoupling hypothesis and instead suggest that behavioral syndromes in species with complex life cycles can be maintained over metamorphosis. Significance statement: A central prediction of behavioral syndromes is that individual behavioral consistency should be maintained over the life of an organism. However, in species with complex life cycles, evolution is thought to act independently on each stage, leading to the prediction that behavioral syndromes should not persist over metamorphosis. We tested for behavioral correlations over metamorphosis by assaying salamander activity, boldness, and exploration in larval and juvenile salamanders. We found support for behavioral syndromes within and between life stages. These findings contradict the predictions of complex life cycle evolution and instead suggest that behavioral syndromes may span metamorphosis. However, because support for the persistence of syndromes over metamorphosis varies between taxa, we caution researchers against extrapolating inferences from the larval stage to the juvenile stage.