Spectral composition of light influences thermoregulatory behaviour in a lacertid lizard (Podarcis muralis)

1. Thermoregulatory set points - i.e. the body temperatures at which heat-seeking or cooling behaviour are initiated - of the lacertid lizard Podarcis muralis were measured by infra-red thermography in animals exposed to light of different spectral compositions. 2. Exposing intact lizards to light from which wavelength < 540 or < 600 nm had been filtered out resulted in persistent but reversible decreases in the values of both thermoregulatory set points. Mean hearing rates and bask durations were also affected. 3. Light from which wavelengths < 480 nm had been removed had no effect on any of these variables. Copyright (C) 1996.