In many animal species, individuals with different color phenotypes often coexist within the same population. Different morphs frequently differ in many other traits, including behavior, morphology, life history and physiology, indicating plastic responses to a variety of selective pressures. The ventral region of the common wall lizard, Podarcis muralis, shows three pure color morphs (yellow, white and orange) and two mosaic morphs (white-orange and yellow-orange). Previous studies have already proved differences in habitat preference and boldness between different morphs. In a study recently published on Acta Herpetologica, Dr. Sreelatha and co-authors further explore the variation in behavioral response to novel environments between morphs.

In 2019, 94 adult males belonging to different morphs were captured in the Cerdanya plateau (eastern Pyrenees). Within 48 hours of capture, each individual was tested in an unfamiliar open field arena. The lizards were allowed to explore the arena for 15 minutes and all their movements were recorded with a video camera. The recorded tapes were then automatically analyzed to track the movement of each lizard and the amount of time spent in different parts of the arena.

The study identified differences in movement and freezing behavior to be correlated with the time of exposure to the novel environment and, possibly, to the age of the individuals. No significant difference, however, was observed between morphs. These results contrast from previous findings on a population of Podarcis muralis from Val d’Aran (North-Eastern Spain), in which yellow morphs exhibited a risk sensitive behavior, while orange and white morphs were risk aversive. 

In order to build a generalized model linking ventral coloration and behavior in the common wall lizard, it is essential to investigate a more extensive range of lizard populations. This investigation should consider various ecological and environmental factors, such as levels of human disturbance, predation pressure, habitat characteristics, and other unknown environmental variables that might influence their behavioral responses.

Read the full paper here.

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