How does rapid body color change affect the conspicuity of lizards to their predators and conspecifics?

Abstract

Predator–prey interactions drive the evolution of prey visual camouflage, but prey species also must remain conspicuous to their conspecifics for social signaling purposes. Whether rapid body color change can help to balance conspecific visibility and predator concealment, in the eyes of each group’s respective visual systems, remains poorly understood. We tested this question using water anoles (Anolis aquaticus), a small lizard that uses rapid dark-to-light body color change to visually camouflage itself from its avian predators across diverse microhabitats. We used digital image analysis and visual modeling to assess the effectiveness of color-matching camouflage in dark- and light-phase A. aquaticus, as perceived by anoles and avian predators. Our findings reveal that A. aquaticus body coloration was perceived similarly by both groups. However, sex-specific differences in overall conspicuousness emerged, with males more consistently color matching their microhabitats compared to females. Females were less likely to color match their backgrounds in their lighter phase, suggesting a sex difference in preferred conspicuity in more exposed habitats. We highlight the context-dependence of color change, with sex-specific differences and microhabitat potentially affecting its function.

Significance statement

Predator and prey visual systems influence prey species’ visual camouflage evolution, but whether rapid body color changes allow animals to dynamically balance conspecific visibility with predator concealment is not well known. We used visual modeling techniques to examine if water anoles (Anolis aquaticus), small lizards that employ rapid body color changes to evade their avian predators, appear differently to their predators and conspecifics depending on color phase. Our findings reveal that A. aquaticus body coloration is perceived similarly by both groups. However, we observed sex-specific differences: males and larger individuals displayed more consistent color matching across different microhabitats, whereas females showed reduced matching in their lighter phase. Our study underscores the context-dependence of the function of color change in relation to factors including sex and microhabitat.