Behavioral flexibility in foraging decision-making and the success of urban dwellers
Theory suggests that animals can maximize their fitness if they are able to tailor their foraging decisions to current environmental conditions. To do this, foraging individuals need to assess the benefits of foraging while accounting for the potential risks of being captured by a predator. Understanding whether and how foraging animals adjust their foraging decisions is crucial to understand how these species respond to the current context of human-induced rapid environmental changes. However, we still know little about how different factors interact to shape these decisions, especially in individual foragers.
To unravel how adjustments in foraging behavior may help animals deal with environmental changes, we conducted a standardized set of manipulative field experiments based on the use of foraging resources in two tropical lizard species, Anolis cristatellus and Anolis sagrei. By replicating these experiments in both urban and natural habitats in Puerto Rico and Florida, we studied: 1) how the presence of conspecifics, predation-risk perception, the abundance of food, and interactions among these factors determine the outcome of foraging decisions; 2) whether and how anoles inhabiting urban environments have adjusted their foraging behavior in a way that maximizes the benefits of their foraging decisions.
In Experiment 1, anoles foraged faster when food was scarce and other conspecifics were present near the feeding tray. Because they took longer to feed when food was abundant or when no conspecifics were present, results suggest that foraging decisions in anoles are the result of a complex process in which individuals assess predation risk by using information from conspecifics while also taking into account food abundance. Experiment 2 confirmed the relevance of risk perception in determining foraging decisions. The use of available perches –where anoles perceive a reduced predation risk as compared to being on the ground- was strongly correlated with latency to feed. Finally, Experiment 3 provided evidence that urban anoles –as compared with those inhabiting natural habitats- show important differences in the decisions they make when foraging. Altogether, our experiments suggest that Anolis lizards are able to maximize their fitness by plastically adjusting their foraging behavior to instantaneous environmental changes. This ability is predicted to be advantageous to persist in human-modified environments, a phenomenon that has been widely reported in a number of Anolis species. Further experimental studies should investigate if this behavioral plasticity is a common pattern allowing some species to thrive in disturbed environments worldwide.