Evolved differences in interaction rules underlie the loss of social behaviors in the Mexican tetra

Animals display a remarkable variety of social behaviors that are necessary for survival. Despite the importance of social behaviors, the neurobiological mechanisms underlying the evolution of such behaviors are largely unknown. The Mexican tetra, Astyanax mexicanus, is a powerful model for studying how behaviors evolve, including social behavior. A. mexicanus exists as a schooling surface form and a non-schooling cave form. Here we have utilized this model in order to investigate how differences in the behavior of individuals result in differences at the level of emergent group social behaviors. We begin by reviewing how fish have contributed to the study of social behavior in Chapter 1, then continue to dissect differences in the schooling and shoaling behavior of adult surface and cave fish in Chapter 2, and finally address ontogenic differences that result in these differences in Chapter 3. All-in-all this, work reveals how evolution may act on the behavior of individuals to produce differences in relevant group behaviors.