Behaviour shapes environmental variation and selection on learning and plasticity: review of mechanisms and implications

Biologists have long been interested in the factors that maintain variation in learning and plasticity within and between species, especially given the role of such flexibility in coping with novel and changing environments. A large body of theoretical and empirical work has established the role of environmental variation in selecting for learning and plasticity, suggesting that simple measures of such variation could serve as proxies for organismal flexibility. However, a wide range of behavioural and physiological traits can shape how organisms experience environmental variation, and thus how plasticity is shaped by selection. Given that these traits themselves can evolve, this sets up the potential for complex feedbacks in the evolution of learning and plasticity. We begin this review by first detailing the wide variety of behavioural traits that shape environmental variation, ranging from exploration and dispersal to sensory biases and habitat choice. We then review relevant theory that suggests how such behavioural traits can modify selection on learning and plasticity, often favouring the evolution of specialization in heterogeneous environments by reducing the variation that organisms experience. When models allow behavioural traits to jointly evolve with plasticity, model outcomes differ and complex evolutionary feedbacks may emerge. We suggest that further theoretical insights could be gained by incorporating more nuances of development and behaviour, such as variation in the developmental window of environmental sensitivity of traits or differences in exploratory periods prior to breeding. Finally, this review discusses implications of this perspective for understanding the maintenance of genetic variation in learning, differences in colonization and survival in novel environments and making predictions about how species will cope with environmental change.