SWALLOW, JG*; GARLAND, T; Univ. of South Dakota; Univ. of California, Riverside: Selection Experiments as a Tool in Evolutionary and Comparative Physiology

A current focus of comparative physiology is understanding how complex traits have evolved, including identification of factors that bias or constrain the evolution of organismal performance capacities. To do this, physiologists have adopted perspectives and tools from modern evolutionary biology, and selection experiments (of various types) have become one of the most important approaches in evolutionary physiology. Mounting evidence demonstrates significant narrow-sense heritability for many physiological traits, and accordingly recent selection experiments have been successful at producing dramatic changes in various traits of interest to comparative physiologists, such as basal metabolic rate and thermal tolerances. Examples include mice that run over 10 miles/day and fruit flies that live more than twice as long as their normal counterparts. Once established, selected lines are useful for understanding basic physiological as well as genetic and evolutionary processes, and may also become important models in biomedical contexts. Selection experiments also allow direct tests of hypotheses concerning general principles of physiological evolution. For example, relatively how rapidly and in what sequence do different types of traits evolve (e.g., behavior vs. morphology vs. life history) when selection is imposed on a complex phenotype? We will introduce several types of selection experiments (e.g., artificial selection, laboratory culling, laboratory natural selection, field introductions) and highlight key methodological and logistical issues that need to be considered when designing one. We will also outline a general strategy for integrating selection experiments into a comparative physiology research program. Supported by NSF IBN-0212567 to T.G.