Meeting Abstract
A long-standing debate revolves around whether phenotypic plasticity facilitates or slows evolution in new environments, yet we largely lack empirical evidence about the relationship between environmental influences on phenotypes and the evolutionary trajectories of populations. We recently showed that traits exhibiting non-adaptive plasticity were the first to adaptively evolve following an experimental introduction of Trinidadian guppies, Poecilia reticulata, that replicated natural colonizations. Specifically, these results demonstrated an overall discordance between the direction of ancestral plasticity and short-term evolution of gene expression levels in the brain. However, here we report that longer-term evolution in similar environments shows the opposite pattern, with the direction of plastic and evolved shifts in brain gene expression levels largely concordant. We argue that these brain transcriptome patterns reflect homeostasis within neural circuits that maintain coherent behavioral outputs despite varied neural states. We summarize how stochastic changes in neural mechanisms in response to novel environments affect the earliest stages of evolution, and contrast that with subsequent evolution that reshapes homeostatic and compensatory mechanisms to stabilize developmental processes and to produce integrated behavioral phenotypes.
