The light-dependent magnetic compass

Abstract

The magnetic compass of many animals, including insects, amphibians, and birds, needs light of a specific wavelength range to function. Behavioral and physiological evidence suggests the involvement of specialized magnetosensitive photoreceptors that enable the animals to perceive the Earth’s magnetic field as a three-dimensional pattern, providing them with information on the axis and inclination of the magnetic field. Cryptochromes have been suggested as the primary receptor molecules, as they are the only known animal photopigment that can produce spin-correlated radical pairs that last long enough for a magnetic field effect to take place. In this chapter, we summarize the state of the art of the research field and discuss the behavioral, physiological, and biophysical evidence for light-dependent magnetic compass orientation in different animals.