Selection on Continuous Reaction Norms: Relating Environmental Change to Selection and Evolution

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

Understanding quantitatively how environmental changes cause selection and evolution is a fundamental challenge for evolutionary biology. We are now in a position to address a variety of fundamental questions about how changes in weather and climate determine selection and evolution. Is selection in the field primarily due to infrequent exposures to extreme (hot or cold) temperatures, or is the frequency of average temperature conditions more important? How does geographic variation in the thermal environment generate differences in selection and evolutionary divergence in traits of organisms that depend on temperature? Can we predict quantitatively how alterations in the thermal environment, such as those due to climate warming, will alter selection and evolutionary responses? To address these questions, the proposed studies will use laboratory and field experiments to test predictions of a quantitative, mathematical model describing selection and evolution. Our studies use temperature effects on growth rate in Pieris rapae (Imported Cabbageworm) caterpillars as a model system; this species has experienced a world-wide expansion of its geographic range during the past 200 years, and is now an important agricultural pest in some regions.