Comparative analysis reveals striking UV reflectance variation according to sex and age in common lizards
Lizards display structural and pigment-based colourations, and their visual system is sensitive to wavelengths of 300-700 nm. However, few studies in squamate reptiles quantified inter-individual colour variation that includes the structural UV component (300-400 nm). Here, we studied variability of a ventral UV/yellow-red ornamentation in the common lizard Zootoca vivipara including an analysis of spatial distribution, sex and age differences. We also investigated whether the expression of colouration is related to body size and condition. Our analyses revealed two distinct patches: a gular patch with a strong UV reflectance and a belly patch with a dominant yellow-red reflectance. Males displayed a less saturated throat colouration with higher UV chroma and UV hue, and had a redder, but duller belly colouration than females. Yearlings had less elaborate ornaments than adults, but already displayed a yellow-red sexual dichromatism on the belly. UV sexual dichromatism was only apparent in adults due to a weaker UV reflectance in females suggesting potential fitness costs of a bright UV colouration in that sex. Different colour traits were related to body size in both sexes, and to body condition in males. We discuss the potential evolutionary scenarios leading to the maintenance of this ornament in common lizards.
Martin, M., Meylan, S., Gomez, D. and J.-F. Le Galliard (2013) Ultraviolet and carotenoid-based colouration in the common lizard Zootoca vivipara (Squamata: Lacertidea) in relationship to age, sex, and morphology. Biological Journal of the Linnean Society 110: 128-141.