Optimal phenotypic plasticity in a stochastic environment minimises the cost/benefit ratio

► Phenotypic plasticity is optimised in the context of a fluctuant environment. ► Covariance matrix is used as a metric of plasticity and to optimise parameters of the model. ► Results lead to speculate that optimised organisms should maximise their exergy. ► A part of genetic diversity could stem in the environment fluctuations. ► Analogies with the MaxEnt method are highlighted and discussed.