Hi Eryn, I would love to be added to the evolutionary biologist feed. I am Javier Abalos, postdoc researcher on lizard coloration and behaviour. Evidence: scholar.google.es/citations?us...

Thanks for this thread, what an eye-opening funny study. When will the plot stop thickening with evolution??

Our discovery reveals a hidden stage in lacertid colour development that reshapes how we understand animal coloration as a signal, reminding us how central development is in communication and sexual selection across nature.

These colour changes may let juveniles avoid costly aggression or courting from adult males, while sparing adults wasted effort on non-competitors/immature mates. As lizards grow, greater colour differentiation may aid recognition and help stabilize social networks.

Could these changes be adaptive? Predation avoidance often explains juvenile colour shifts, but in P. muralis that’s unlikely. Instead, a social role seems more plausible: ventral colour is usually hidden, yet adults display throats & flanks in social encounters

By the end of their first year, most juveniles show adult-like ventral colours. But only some, mostly males, develop UV-blue spots on their flanks, and these look still very different from adult ones to conspecifics.

We found:

🦎 Hatchlings look white to us, but reflect far more UV than adults.

🦎 This “UV+white” is distinct and visible to lizards.

🦎 Ventral colours and UV flank spots develop out of sync.

🦎 Males and females diverge in timing and pattern.

In our “new” study (it’s from 2018, research goes slowly…), we tracked wall lizards from hatching to one year of age. We reared them in semi-natural conditions, measured their colours using spectrophotometry, and modeled how other lizards perceive them.

Wall lizards (Podarcis if you're feeling fancy) are famed for dazzling color diversity matched by a UV-sensitive vision system. The widespread P. muralis shows ventral & lateral colors—including UV-reflecting spots and alternative throat colors— which likely play a role in social communication

Spectrophotometry shows that UV colours are widespread in nature, and visual models can help to reveal its meaning. UV often acts as a private communication channel invisible to many animals. Flowers may seem flamboyant to us, but their colours are tuned to dazzle bees.