Dr. Ilia Solov'yov
Frankfurt Institute of Advanced Studies and Physics Department, University of Frankfurt
Frankfurt, Germany

Monday, September 15, 2008
4:00 pm (CT)
3169 Beckman Institute

Abstract

Many birds are able to orient themselves accurately when the sun or the stars are not visible (e.g. on very cloudy days or nights). Many studies have established that birds employ then the Earth's magnetic field as a compass, e.g., European robins, and pigeons. The birds, apparently, are also sensitive to slight temporal and spatial variation in the magnetic field that is potentially useful for determining location. We study a putative avian magnetoreception mechanism, which is based on the interaction of two iron minerals (magnetite and maghemite) experimentally observed in subcellular compartments within sensory dendrites of the upper beak of several bird species. The iron minerals in the beak form platelets of crystalline maghemite and clusters of magnetite nanoparticles. We develop a theoretical model to quantitatively describe the interaction between the iron-mineral containing particles, and demonstrate that depending on the external magnetic field the external pull or push to the magnetite clusters may reach a value of 0.4 pN. This is principally sufficient to excite specific mechanoreceptive membrane channels leading to different nerve signals and causing a certain orientational behavior of the bird.