Many chameleons have the remarkable ability to exhibit complex and rapid color changes during social interactions. A collaboration of scientists within the Sections of Biology and Physics of the Faculty of Science from the University of Geneva (UNIGE), Switzerland, unveils the mechanisms that regulate this phenomenon. In a study published in Nature Communications, the team led by professors Michel Milinkovitch and Dirk van der Marel demonstrates that the changes take place via the active tuning of a lattice of nanocrystals present in a superficial layer of dermal cells called iridophores. The researchers also reveal the existence of a deeper population of iridophores with larger and less ordered crystals that reflect the infrared light. The organisation of iridophores into two superimposed layers constitutes an evolutionary novelty and it allows the chameleons to rapidly shift between efficient camouflage and spectacular display, while providing passive thermal protection.
Photos: Male panther chameleons (Furcifer pardalis) photographed in Madagascar
credits: Michel Milinkovitch – Université de Genève