Behavioral Plasticity

Dendropsophus ebraccatus tadpoles are known to have plastic morphological development when reared in the presence of different predator cues, including induced differences in tail shape and coloration. Other aspects of the phenotype, including variation in behavior, have remained unexplored. 

To address this gap, I measured the movement of 315 11-day-old tadpoles that had been raised in the presence of chemical cues from dragonfly nymphs (Anax amazili) or fish (Astyanax ruberrimus) predation or with predator-free control water. Tadpoles from each rearing environment were then tested with each type of cue, creating nine different rearing environment by test cue combinations, to distinguish the effects of developmental exposure from immediate plastic responses. 

Tadpoles showed a strong phenotypic response based on both their rearing environment and their test cue. Additionally, measures of morphological, coloration and behavioral (movement) plasticity all showed opposing phenotypes to the chosen predators. 

Despite similar patterns found across all three plastic phenotypes, analysis at a sibling level reveled an association between morphological and coloration plasticity, but not behavioral plasticity. This result indicates that while certain elements of the overall plastic phenotype develop together, other aspects develop independently. More generally, this result emphasizes the importance of exploring individual and family-level variation in studies of developmental and phenotypic plasticity.