Subterranean Fishes of the World

5626

2022

AIM 2022

32

Social behaviors are remarkably diverse throughout the animal kingdom, and vary both within and between species. Social behaviors contribute to a variety of processes necessary for survival including predator evasion, foraging, and reproduction. Despite the importance of social behaviors, the mechanisms driving their diversity across natural populations are poorly understood. Ease-of-care, small size, and amenability to genetic modification and whole-brain imaging make certain species of fish particularly powerful for investigating these mechanisms. Moreover, social behaviors are well-studied in fish and can broadly be broken down in to the well-defined behaviors schooling and shoaling, making this system particularly attractive for studying the evolution of complex behaviors. Shoaling is a group behavior characterized by the aggregation of individuals into a social group and schooling is a type of specialized shoaling characterized by synchronized motion of individuals. Although these are complex plastic behaviors, they can be readily studied using modern recording and automated tracking technologies, making them ideal for investigating the mechanisms that underlie the evolution of diverse social behaviors. The small freshwater fish, Astyanax mexicanus, is exceptionally well-suited for studying these and other social behaviors because of the existence of multiple geographically isolated populations that exhibit robust differences in sociability. River-dwelling surface fish are highly social, and exhibit robust schooling and shoaling, unlike cave-dwelling fish in which these behaviors are significantly reduced or absent. Here we examine the behavior of surface fish and cavefish across multiple developmental time points to show the emergence of schooling and shoaling during development in surface fish. We find that surface fish and cavefish exhibit significantly different social tendencies throughout development. , but that cavefish are not entirely asocial. This work describes the ontogeny of collective behaviors in closely related populations that display divergence in social behavior, and provides a platform for understanding the genetic and neural mechanisms underlying diversity in social behaviors.

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