A variety of environmental factors (e.g. invasive species, climate change) threaten native biodiversity. Understanding the mechanisms that enable organisms to respond to environmental change is critical. Much research has focused on the ability of organisms to rapidly evolve or alter the expression of traits (phenotypic plasticity) in response to environmental changes. However, it is now becoming clear that the environment can induce phenotypic changes that span multiple generations. This ‘transgenerational plasticity’ (TGP) occurs when the environment experienced by parents induces significant changes in offspring and subsequent generations. While there exist numerous examples of TGP that are assumed to be adaptive and thus shaped by natural selection, our understanding of the evolution of TGP in nature is limited. New theory predicts that temporal stability is a key driver of the evolution of TGP. We tested this prediction using natural populations of zooplankton (Daphnia ambigua) from lakes in Connecticut that that span a gradient in the form and intensity of predation by a dominant fish predator, the alewife (Alosa pseudoharengus).
Results/Conclusions
We found that the trajectory of evolution depended strongly upon intraspecific variation in the predator community. Temporal variation in alewife predation (due to connections with the coastal ocean) selects for within-generation plasticity while consistently strong (or weak) mortality (in lakes not connected to the ocean) selects for increased transgenerational plasticity. Such results illustrate the important role that the ecological community plays in the evolution of phenotypic plasticity and also argue that divergent ecological conditions select for phenotypic responses within and across generations.