Individual quality and nuptial throat colour in male European green lizards

Abstract

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.

Chameleons communicate with complex colour changes during contests: different body regions convey different information

“…Because chameleon display coloration and change has never been quantitatively analysed with respect to intraspecific variation in behaviour, we measured the amount and speed of colour change, as well as maximum display brightness ( previously suggested to be an informative component of squamate colour signals [16]). We measured colour changes as: (i) the perceptual distance travelled (sum of distances between colour measurements taken at different times) and (ii) rate of colour change ( perceptual distance/time), both measured using units of just noticeable differences, which capture perceivable changes in colour taking into account species-specific photoreceptor sensitivities [13,17] (see electronic supplementary material, S4).…”

Stable correlation structure among multiple plumage colour traits: can they work as a single signal?

“…In addition, year‐specific environmental conditions may exert major influences on sexual signal expression (Saino et al ., ; Molnár, Bajer & Török, ; Scordato, Bontrager & Price, ) and there may be different year‐specific effects on different ornaments of the same species (Hegyi et al ., ). This may cause among‐year variation in the magnitude and pattern of integration among multiple ornamental traits.…”

Effects of energy and thermoregulation time on physiological state and sexual signal in a lizard

“…Production and maintenance of structural colors have been shown to be energetically costly (Megía‐Palma, Martínez, & Merino, ; Prum, ), with both developmental stress and available nutrients influencing coloration in lizards (Olsson et al., ). Additionally, previous studies showed that nuptial throat coloration is condition dependent (Molnár et al., ) and affected by environmental factors (Bajer et al., ) in the study species. Previously, it was found that the development of the throat patch color right after the hibernation was affected by basking time and not by available energy (Bajer et al., ).…”

“…In contrast, structural coloration (blue and ultraviolet (UV)) is caused by light scattering and/or reflective microstructures in the dermal tissue (Olsson, Stuart‐Fox, & Ballen, ). Intense sexual coloration may increase predation risk (Pascual, Senar, & Domenech, ) and conspecific aggression (Kotiaho, ) and the production of both types of color signals can be energetically costly (Grether et al., ; Hurst, ) and condition dependent (Keyser & Hill, ; Molnár, Bajer, Török, & Herczeg, ). It has been demonstrated in a wide range of taxa that environmental constraints affecting survival and reproduction of animals can significantly influence expression and evolution of pigment based color signals (Blanco, Frias, Garrido‐Fernandez, & Hornero‐Mendez, ; Casagrande, Costantini, Tagliavini, & Dell'Omo, ).…”

“…Additionally, suboptimal environmental temperature significantly decreased UV color development (Bajer et al., ). Different throat color components act as a condition‐dependent multiple signaling system (Molnár et al., ), conveying information about blood parasite infection (Haemogregarinidae) (Molnár et al., ) and spatial strategies (Molnár, Bajer, Szövényi, Török, & Herczeg, ). Hence, it is an ideal model to study how environmental factors may simultaneously affect sexual signal intensity and physiological state, helping us to form testable hypothesis about the physiology–sexual signal link.…”