Meeting Abstract
Rapid anthropogenic changes in the environment are imposing shifts in the patterns of selection on local populations. Behavior has long been considered a primary means of rapid response to environmental challenges given its often exceptional plasticity. When behavioral plasticity is adaptive it can rescue populations from extinction (Baldwin Effect), although plastic responses to novel environments need not be adaptive. The adaptive radiation of the threespine stickleback fish offers an unusual opportunity to evaluate factors that influence the patterns of plasticity and evolutionary responses to selection in a recent adaptive radiation. Ancestral patterns of plasticity can be inferred from regional oceanic populations likely to represent the ancestral condition relative to populations established since the last glacial retreat was initiated approximately 12,000 years ago. Comparisons among multiple ancestral (oceanic) populations and derivative freshwater populations of several ecotypes indicate that in some cases the responses to anthropogenic environmental modification reflect ancestral patterns of environmental variation. The responses in some cases involve modification ancestral patterns of plasticity and in one case apparent loss of plasticity (genetic assimilation). Evolutionary responses to anthropogenic habitat modification (predator introduction, increased productivity) have also led to contemporary evolution of plastic phenotypes, apparently including learning, over periods as short as 20 years, and to the re-emergence of ancestral traits that in multiple populations exhibit parallel evolutionary inhibition of a complex behavior. The evidence indicates that in this radiation at least, responses to anthropogenic modification of the environment will be complex, but in some cases predictable.
