Plasticity in social communication and its implications for the colonization of novel habitats

Behavioral plasticity is expected to facilitate the colonization of novel habitats by allowing populations to respond rapidly to abrupt environmental change. We studied contextual plasticity—a form of plasticity that allows an immediate phenotypic response to stimuli—in the territorial communication of Puerto Rican Anolis lizards and considered the role it might play in facilitating colonization. In these lizards, the detection of territorial visual displays by receivers is acutely dependent on fluctuating levels of visual noise from windblown vegetation and ambient light. We quantified the contextual reaction norms of various components of the territorial displays of individual lizards as a function of visual noise and light for one focal population over many weeks of observation. We then compared these contextual reaction norms to the displays given by closely related Anolis species found in other environments to assess the extent to which colonizing lizards might be capable of performing displays similar to those likely to be effective in those environments. Our results suggest that lizards are able to rapidly adjust their territorial displays in ways that might help them communicate in other (but not all) habitat types on Puerto Rico. Given that the contextual plasticity of animal signals can be measured in free-living animals far more easily than other forms of behavioral plasticity, our study presents animal communication as a tractable model for tackling broad questions in how phenotypic plasticity might facilitate colonization, adjustment to environmental change, and adaptation.