Format: ORAL

Maria Stefania Przybylska1,2,3, Cyrille Violle1, Denis Vile2, JF Scheepens3, Lo Delalandre1, Lily Bennett1, Eric Garnier1, Franois Vasseur1

1 CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France 2 LEPSE, Univ Montpellier, INRAE, Institut Agro Montpellier, Montpellier, France 3 Goethe University Frankfurt, Frankfurt am Main, Germany

The study of ecological strategies, i.e. sets of covarying traits that match with environmental conditions in a potential adaptive way, helps to address the role of the phenotype as a whole, rather than individual traits, in adaptation. Because, in the field, covariation between environmental conditions makes it difficult to test for the concrete factors driving ecological strategies, experimental approaches can be valuable. Using experimental evolution, we tested for the evolution of both mean phenotypes and their variance in response to contrasting levels of stress (resource availability) and disturbance (herbivory) in Arabidopsis thaliana. By tracking the phenotypic space formed by whole-plant and leaf traits, we found that, after only three generations, A. thaliana populations diverged both in terms of phenotypic variation and trait syndromes in response to contrasting resource and herbivory treatments. The most divergent responses were found to evolve under low and high resources without herbivory: a strategy of fast-growth for stress escape and a strategy of slow-growth for competitive ability, respectively. Furthermore, these strategies have been shown to be adaptive and possibly density-dependent. Our results highlight the rapid evolution of plant strategies in response to stress and disturbance and the key importance of population size in ecological analyses.