Meeting Abstract

S8.2-2  Monday, Jan. 6 11:00  Plasticity and constraints on the evolution of body shape: Phenotypic integration in locally adapted Trinidadian guppy populations HANDELSMAN, Corey A*; WALKER, Jeffrey A; GHALAMBOR, Cameron K; Colorado State University; University of Southern Maine; Colorado State University chandelsman@gmail.com

A major problem in evolutionary biology is to understand the dual nature of the environment as a source of natural selection and phenotypic plasticity. The degree to which plasticity constrains or facilitates adaptive evolution remains unresolved. Theory suggests that the degree to which plasticity in complex traits is integrated should constrain how much individual traits are free to evolve and respond to selection. The colonization of novel environments can induce phenotypic plasticity and comparisons between ancestral and derived populations can provide key insights into how integrated traits respond to directional selection. Body shape is a complex phenotype that is likely to show strong integration of constituent traits due to consequences for functional design and swimming performance. We tested the relationship between plasticity and evolutionary divergence in body shape by rearing locally adapted Trinidadian guppy populations in common gardens that simulated their ancestral (high) and derived (low) predation environments. Guppy populations adapted to high and low predation environments exhibited differences in body shape, and the presence or absence of predator cues also induced changes in shape. We compared these findings to four experimentally established populations that were introduced into low predation environments. Patterns of plasticity and phenotypic integration in body shape in the ancestral and derived populations were compared to identify constraints on the evolution of body shape and to determine how they can jointly influence the evolution of body shape in wild populations of guppies.