David Money, Brigham Young University
Life Sciences
Interest in animal personalities, and particularly the effect that different environments have on personality, has increased dramatically over the past decade. Understanding how individuals vary in their behavior, and if there are consistent differences among populations from divergent selective environments, lays the foundation for studies focusing on the contribution of divergent behavior in species formation. To date, studies that have focused on how personalities differ across ontogenetic stages have failed to compare populations that occur in dramatically different environments. Our study attempts to fill this void by studying the ontogeny of personality in populations that have evolved in environments with different levels of risk (i.e., predation vs. no-predation). We tested the expression of different personality traits evolution across ontogeny (i.e., from juveniles to full grown adults) in two sister species of live-bearing tropical fish, Brachyraphis roseni and B. terrabensis. These species have evolved in different selective environments, with B. roseni having evolved in an environment where predators were present, while B. terrabensis evolved in an environment lacking predators. We assessed the boldness expression of individuals from several groups in populations, namely juveniles, small adults, and large adults. To measure boldness, we used an emergence test, and also an exploration and activity test (i.e., ratio of movement to idleness during an allotted time period). Our study provides evidence for an important relationship between predation environment and the evolution of personality traits across ontogeny.