Meeting Abstract

S11.10  Wednesday, Jan. 6  Multifarious selective agents and diverse trait functions: Poeciliids shed light on the evolution of fish morphology LANGERHANS, R.B.; University of Oklahoma langerhans@ou.edu

The evolution of body and fin size and shape in fishes is undeniably complex. Body/fin form can experience both direct and indirect selection from numerous selective agents in the wild. For instance, morphology can exhibit a direct link to fitness via sexual selection when members of the opposite sex exhibit morphology-biased mating preferences. Further, fish morphology typically experiences indirect natural (and sexual) selection from various selective agents via its influence on numerous performance variables (e.g., locomotion, feeding, oxygen extraction). Put simply, a multitude of factors affects the evolution of fish morphology, as body/fin traits must function reasonably well at an array of diverse tasks. Such a scenario may drive morphological differentiation and speciation, but also can cause the evolution of fish morphology to be highly unpredictable. Here I examine a conceptual framework for studying the evolution of morphological diversity and its predictability using livebearing fishes (Family Poeciliidae) as a model system. Focusing on links between morphology and mating behaviors, and between morphology and locomotor performance, I conceptually elucidate the ways that selection can act on fish morphology, highlight connections presumably most important in the wild, pinpoint areas most in need of future work, and review and synthesize existing data to investigate the relative importance of various selective agents and forms of selection in shaping fish morphology in both predictable and unpredictable manners.