2014/07/24 by Roswitha Wiltschko, Wolfgang Wiltschko · 1 citation
Biochemistry, Genetics and Molecular Biology · Environmental Science · Medicine · Neuroscience · Mathematics · #Electromagnetic Fields and Biological Effects #Marine animal studies overview #Spaceflight effects on biology #Magnetoreception #Cryptochrome #Compass #Earth's magnetic field #Photopigment #Magnetic field #Orientation (vector space) #Biophysics #Wavelength #Physics #Optics #Biology #Geometry #Neuroscience #Mathematics #Circadian clock
paper · pdf · doi:10.3390/bios4030221
openalex publication_date 2014/07/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
Birds can use the geomagnetic field for compass orientation. Behavioral experiments, mostly with migrating passerines, revealed three characteristics of the avian magnetic compass: (1) it works spontaneously only in a narrow functional window around the intensity of the ambient magnetic field, but can adapt to other intensities, (2) it is an "inclination compass", not based on the polarity of the magnetic field, but the axial course of the field lines, and (3) it requires short-wavelength light from UV to 565 nm Green. The Radical Pair-Model of magnetoreception can explain these properties by proposing spin-chemical processes in photopigments as underlying mechanism. Applying radio frequency fields, a diagnostic tool for radical pair processes, supports an involvement of a radical pair mechanism in avian magnetoreception: added to the geomagnetic field, they disrupted orientation, presumably by interfering with the receptive processes. Cryptochromes have been suggested as receptor molecules. Cry1a is found in the eyes of birds, where it is located at the membranes of the disks in the outer segments of the UV-cones in chickens and robins. Immuno-histochemical studies show that it is activated by the wavelengths of light that allow magnetic compass orientation in birds.