Individual quality and nuptial throat colour in male European green lizards

Nuptial traits signalling individual quality are common in numerous animal taxa, and play a significant role in sexual selection. Detecting female mate choice based on visual cues is notoriously hard in lizards. Previously, we found that female European green lizards (Lacerta viridis) preferred to associate with males with high ultraviolet (UV) throat reflectance. Here, we investigated if different components of nuptial throat colour of male European green lizards were correlated to other fitness-related traits, and thus could signal male quality. We found that (1) high UV chroma correlates positively with directional asymmetry and shows a negative trend with body condition; (2) blue chroma is not related to any individual traits; and (3) total throat brightness correlates positively with body size and relative head size, and negatively with ectoparasite load. Our results suggest that having high throat UV reflectance is costly for male European green lizards, so probably only high-quality individuals can afford it, while total brightness of the throat colour signals age, relative head size and health status. Hence, throat colour in male European green lizards is a multiple honest signal.