Cryptic Ontogenetic Changes in the Ventral Coloration of a Color Polymorphic Wall Lizard (Podarcis muralis)

Area of Science:

• Ethology
• Animal coloration
• Visual perception

Background:

• Ontogenetic color changes (OCCs) are common in animals but often overlooked, especially when involving ultraviolet (UV) wavelengths.
• Wall lizards (Podarcis muralis) can perceive UV light, suggesting their coloration plays a role in social communication.

Purpose of the Study:

• To describe the ontogenetic color changes in the ventral and ventrolateral coloration of juvenile common wall lizards.
• To assess the detectability of these color changes by conspecifics using visual modeling.

Main Methods:

• Measured spectral reflectance of ventral and ventrolateral scales in hatchling, yearling, and adult wall lizards.
• Utilized visual modeling to estimate chromatic distances between different life stages and sexes.

Main Results:

• Hatchlings display UV-enhanced white (UV+white) ventrally, which is discriminable from adult throat and OVS colors.
• UV+white decreases with age, with slower changes in female bellies.
• UV-blue coloration in male OVS develops later than throat and belly color changes.

Conclusions:

• Ontogenetic color changes in wall lizards are perceptible to conspecifics, supporting their role as social signals.
• These color changes likely mediate interactions between juveniles and adults, potentially delaying the onset of adult communication signals.