First description of colour changes in the wall lizard during growth, invisible to the human eye and with a possible communicative function
A study by the Cavanilles Institute of Biodiversity and Evolutionary Biology at the University of Valencia (UV) has described changes in the ventral and lateral colouration of a species of lizard typical of the northern Iberian peninsula, Podarcis muralis (or wall lizard). The research shows that these changes, some of which are invisible to the human eye, may serve communicative functions by mediating social interactions. The study has been published in the Journal of Experimental Zoology Part A: Ecology and Integrative Physiology.
30 de september de 2025
This is the first detailed description of ontogenetic colour changes (OCCs, changes occurring during development) in the ventral and ventrolateral colouration of Podarcis muralis. The study analysed the ultraviolet (UV) component of the lizards’ colouration using reflectance spectrophotometry, from hatching through to the first year of life. “Although the colours of adults of this species were already known, the colouration of juveniles and how it develops had not been characterised”, explains Javier Ábalos, lead author of the article and postdoctoral researcher in the Department of Ethology at the Cavanilles Institute.
The researchers identified a type of white in lizard hatchlings that was previously unknown in the species (white with UV reflectance), which is noticeably different from adult white (white without UV), clearly differentiating juveniles from adults in the eyes of other lizards. In addition, for the first time, the study documents a delay in the development of UV-blue patches on the flanks in relation to the yellow, orange or non-UV white colouration on the throat and belly, as well as marked sex differences.
The research team, which also includes Alicia Bartolomé, Guillem Pérez i de Lanuza and Enrique Font (Cavanilles Institute), suggests that these colours probably play a role in social communication. The young are born with an apparently white throat and belly. The development of ventral colouration and UV-blue lateral patches occurs asynchronously and differs between sexes.
“Although predation often explains juvenile colour changes, in P. muralis this seems unlikely, as the variation mainly affects ventral colouration, which is usually hidden. A role in intraspecific communication is more plausible, since adults display their throats and flanks during social interactions”, notes Guillem Pérez i de Lanuza. “These changes may help adults recognise juveniles and reduce their aggression towards them, favouring coexistence between adults and young”, adds Javier Ábalos.
The study received funding from a Margarita Salas grant awarded to Javier Ábalos (ref. MS21-053), an FPU grant to Alicia Bartolomé (ref. FPU18/04021) and an FCT grant (ref. SFRH/BPD/94582/2013) and a Juan de la Cierva-Incorporación grant (ref. IJC2018-035319-I) to Guillem Pérez i de Lanuza. It was also supported by project AICO/2021/113 from the Valencian Department of Innovation, Universities, Science and Digital Society, and project PID2019‐104721GB‐I00 from the Spanish Ministry of Science and Innovation. The study also involved Thomas Deruelles (Centre National de la Recherche Scientifique, France, and Charles Sturt University, Australia).
Article reference:
Ábalos, J., Bartolomé, A., Pérez i de Lanuza, G., Aubret, F., & Font, E. (2025). Cryptic ontogenetic changes in the ventral coloration of a polymorphic lizard (Podarcis muralis). Journal of Experimental Zoology Part A: Ecology and Physiology, in press. https://doi.org/10.1002/jez.70035
Caption:
Juvenile female (less than one year old) of Podarcis muralis. Photographs taken with a camera sensitive to the UV spectrum: one with a filter transmitting only visible light (as perceived by the human eye), and another, in black and white, with a filter transmitting only near-ultraviolet light.