DERMAL PHOTORECEPTORS REGULATE BASKING BEHAVIOR IN THE LIZARD PODARCIS-MURALIS

There is evidence that dermal photic responsiveness can be found in a wide range of animals. Behavioral responses to dermal stimulation by l ight have been observed in pigeon squabs and new-born rats, and more r ecently in a sea snake. Here we report that painting the dorsal surfac e of the lizard (Podarcis muralis) with opaque black paint impairs the animal's ability to position itself beneath a light source containing negligible heat. Experiments using light of different spectra and int ensities show that the effect is due to light of wavelengths shorter t han 600 nm and of intensity higher than 2.5 mW cm(-2). These experimen ts demonstrate for the first time that overt behavior in a terrestrial vertebrate can be mediated by a dermal light sense.