Magnetoreception in the wood mouse (Apodemus sylvaticus): influence of weak frequency-modulated radio frequency fields.
The mammalian magnetic sense is predominantly studied in species with reduced vision such as mole-rats and bats. Far less is known about surface-dwelling (epigeic) rodents with well-developed eyes. Here, we tested the wood mouse Apodemus sylvaticus for magnetoreception using a simple behavioural assay in which mice are allowed to build nests overnight in a visually symmetrical, circular arena. The tests were performed in the ambient magnetic field or in a field rotated by 90°. When plotted with respect to magnetic north, the nests were bimodally clustered in the northern and southern sectors, clearly indicating that the animals used magnetic cues. Additionally, mice were tested in the ambient magnetic field with a superimposed radio frequency magnetic field of the order of 100 nT. Wood mice exposed to a 0.9 to 5 MHz frequency sweep changed their preference from north-south to east-west. In contrast to birds, however, a constant frequency field tuned to the Larmor frequency (1.33 MHz) had no effect on mouse orientation. In sum, we demonstrated magnetoreception in wood mice and provide first evidence for a radical-pair mechanism in a mammal.
Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany.
E Pascal
EP
Malkemper
Department of Earth and Environmental Sciences, Geophysics, Munich University, 80333 Munich, Germany.
Stephan H K
SH
Eder
Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany.
Sabine
S
Begall
Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America.
John B
JB
Phillips
1] Faculty of Physics, University of Duisburg-Essen, 47057 Duisburg, Germany [2] Department of Earth and Environmental Sciences, Geophysics, Munich University, 80333 Munich, Germany.
Michael
M
Winklhofer
Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521 Praha 6, Czech Republic.
Vlastimil
V
Hart
1] Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, 45117 Essen, Germany [2] Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521 Praha 6, Czech Republic [3] Faculty of Science, University of South Bohemia, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
Hynek
H
Burda
D000818:Animals; D060733:Electromagnetic Radiation; D060526:Magnetic Fields; D051189:Murinae / Q000502:physiology*; D009425:Nesting Behavior / Q000502:physiology; D009949:Orientation / Q000502:physiology*; D011846:Radio Waves; D012677:Sensation / Q000502:physiology*