Phenotypic plasticity, global change, and the speed of adaptive evolution.

The role phenotypic plasticity might play in adaptation to the ongoing climate changes is unclear. Plasticity allows for the production of a diversity of intra-generational responses, whose inter-generational evolutionary consequences are difficult to predict. In this article, we review theory and empirical studies addressing this question in insects by considering three scenarios. The first scenario corresponds to adaptive plasticity that should lead to slow or no evolution. The second scenario is the case of non-adaptive phenotypic plasticity to new environmental conditions that should lead either to extinction or, on the contrary, to rapid evolutionary change. The third scenario deals with how plasticity alters the variance selection acts upon. These scenarios are then discussed by highlighting examples of empirical studies on insects. We conclude that more studies are needed to better understand the relationship between phenotypic plasticity and evolutionary processes in insects.