Patterns of variations in dorsal colouration of the Italian wall lizard Podarcis siculus

Research on animal colouration has grown exponentially in the last decade thanks to multidisciplinary approaches. Most studies were focused on trade-offs between communication and mimicry, which represent the two main constraints and drivers of the evolution of body colourations. Reptiles are excellent model species in order to investigate such field of study and lizards in particular show great variability of body colourations and their functions. We studied the lizard Podarcis siculus analysing the variations of dorsal colour of three populations and we obtained clear patterns of seasonal and ontogenetical variation of dorsal colour. According to baseline colour, males were greener and brighter than females, although no difference in saturation was recorded. According to seasonal variations, analyses showed that both sexes significantly vary in colour during the year: males reached higher peaks of hue and saturation later than females during spring; contrastingly, females showed higher peaks of brightness, reached earlier similarly to hue and saturation. Ontogenetic variations were recorded only in males, which become greener, less bright and saturated with growing size. Therefore, our results suggest the occurrence of two opposed strategies in colour expression between sexes: males' dorsal colouration plays a major role in communication, while females are more crypsis-oriented.