Three yellow patches differently correlate with exploratory behaviour, morphological traits, leukocytes, parasites, and hormones in a lizard species

Multiple within-individual non-redundant signals that convey complementary information about individual quality may have evolved in lacertid lizards (i.e., the multiple signal hypothesis ––MSH). We tested this hypothesis in a short-living species, Acanthodactylus erythrurus. We quantified the spectrophotometric reflectance of three colour patches that look yellow to the human eye and that have the typical body scheme distribution of the Lacertidae (namely cheek, lateral eyespots, and outer ventral scales) in adult males. An ultraviolet component of the three “yellow” patches is revealed by spectrophotometry. We modelled the spectral properties of these patches using model averaging and cross-validation as a function of head volume and body length (proxies of resource allocation to somatic growth), the exploratory behaviour upon a stressing situation (proxy of quality to cope with stress), body condition (proxy of nutritional state), leukocytic profiles (proxy of immune state), and faecal testosterone metabolites (proxy of reproductive state and aggression). The spectral within-individual significant differences between the three “yellow” patches together with the different relationships with the independent predictors analysed, suggested that although the three colour patches look similarly yellow to the human eye their differential expression may be influenced by patch-specific pigment allocation rules. Furthermore, the results found between the exploratory behaviour, morphological traits, leukocytic profiles, ectoparasites, and hormones with the spectral properties of the three yellow patches of A. erythrurus support that male nuptial colouration of this lizard species honestly reflect male quality and provide further support for the MSH in lacertids.