Speaker
Description
Theory predicts that adaptive plasticity in fitness-related traits may play a key role in establishment in novel environments, persistence in changing environments, and allopatric speciation. Yet testing these hypotheses is difficult, especially at the macroevolutionary level, due to the inherent difficulty of measuring plasticity. We exploit recent methodical advances to estimate the strength of plasticity and the environmental dependence of selection, the two key parameters linking plasticity and local adaptation, from observational data from a large-scale database of over one million individual records of adult damselflies and dragonflies and corresponding spring temperatures. Our aim is to elucidate the role that temperature-induced plasticity in timing of metamorphosis (phenological plasticity), a key life history transition, plays in macroevolutionary diversification. Specifically, we predict that: 1) the strength of plasticity should coevolve with the environmental dependency of selection and 2) the contribution of plasticity to local adaptation should be highest in extreme/recently colonized environments. Our analysis of over one million records from 49 species supports both predictions. First, we find correlated evolution of the strength of plasticity and the environmental dependence of selection. Second, we show that the contribution of phenotypic plasticity to within-species local adaptation increases during the recent, post-glaciation colonization of Northern regions. Our results suggest that phonological plasticity may have played an important role in temperate diversification in these insects. Moreover, an extensive long-term database of selection in wild populations allows the unique opportunity to validate these novel comparative approaches to the study of phenotypic plasticity.
