Predation Risk Perception, Food Density and Conspecific Cues Shape Foraging Decisions in a Tropical Lizard

Abstract

When foraging, animals can maximize their fitness if they are able to tailor their foraging decisions to current environmental conditions. When making foraging decisions, individuals need to assess the benefits of foraging while accounting for the potential risks of being captured by a predator. However, whether and how different factors interact to shape these decisions is not yet well understood, especially in individual foragers. Here we present a standardized set of manipulative field experiments in the form of foraging assays in the tropical lizard Anolis cristatellus in Puerto Rico. We presented male lizards with foraging opportunities to test how the presence of conspecifics, predation-risk perception, the abundance of food, and interactions among these factors determines the outcome of foraging decisions. In Experiment 1, anoles foraged faster when food was scarce and other conspecifics were present near the feeding tray, while they took longer to feed when food was abundant and when no conspecifics were present. These results suggest that foraging decisions in anoles are the result of a complex process in which individuals assess predation risk by using information from conspecific individuals while taking into account food abundance. In Experiment 2, a simulated increase in predation risk (i.e., distance to the feeding tray) confirmed the relevance of risk perception by showing that the use of available perches is strongly correlated with the latency to feed. We found Puerto Rican crested anoles integrate instantaneous ecological information about food abundance, conspecific activity and predation risk, and adjust their foraging behavior accordingly.

Urbanization and biological invasion shape animal personalities

“…This suggests that being cautious favors persistence of lizards in novel, potentially risky, environments such as urban habitats (Marzluff et al ., ; McKinney, ; Sol et al ., ), whereas this is not necessarily beneficial in more predictable natural forest habitats. In fact, in a foraging context, Anolis cristatellus (a species ecologically similar to A. sagrei ) follow a decision‐making process in which they balance the potential costs and benefits of intraspecific competition and predation (Drakeley et al ., ). Our findings suggest that, by being more tolerant of humans but more cautious when faced with new challenges, urban lizards may be more likely to successfully respond to changes in the environment.…”

“…To further assess the ecological relevance of the behaviors measured in captivity, we conducted an experiment in freeranging A. sagrei that encompasses several components of risk-taking behavior (namely visual exploration, boldness to descend to the ground, and food innovation). We based our experiment on the fact that A. sagrei spend most of their time perched on vegetation while scanning the ground for potential prey, primarily arthropods (Stamps, 1977;Losos, 2009;Drakeley et al, 2015). They tend to abandon this posture when fed to satiation (Stamps, 1977;Drakeley et al, 2015).…”

“…We based our experiment on the fact that A. sagrei spend most of their time perched on vegetation while scanning the ground for potential prey, primarily arthropods (Stamps, 1977;Losos, 2009;Drakeley et al, 2015). They tend to abandon this posture when fed to satiation (Stamps, 1977;Drakeley et al, 2015). We tested the willingness of free-ranging lizards to feed from new resources by presenting a live mealworm on the ground at a distance of 1 m from an A. sagrei perched in survey posture.…”

Hunt or hide: How insularity and urbanization affect foraging decisions in lizards

“…Unfortunately, not enough data were collected on this neophilic behaviour. Nevertheless, regardless of the impact of the novel object, the islet lizards should still have been more willing to go to the food and should spent more time investigating the petri dish to get the food, if arthropod prey is indeed scarce on islets (Drakeley, Lapiedra, & Kolbe, ; Janzen, ; Lima & Dill, ; Olesen & Valido, ). Future studies should validate whether arthropods are indeed less abundant on these islets.…”

The perils of city life: patterns of injury and fluctuating asymmetry in urban lizards

“…The magnitude and direction of the effect of urbanization on body condition may be influenced by resource distribution, as well as by ecological factors related to foraging. For instance, even if food is locally more abundant at urban sites, higher competitor densities or altered predation pressures may influence an individual's willingness and success in exploiting food resources in lizards (Drakeley et al, 2015). In some species, this could result in greater hesitancy to feed on novel items in an urban setting (Chejanovski et al, 2017).…”