title: Use of a light-dependent magnetic compass for y-axis orientation in European common frog (Rana temporaria) tadpoles.
abstract: We provide evidence for the use of a magnetic compass for y-axis orientation (i.e., orientation along the shore-deep water axis) by tadpoles of the European common frog (Rana temporaria). Furthermore, our study provides evidence for a wavelength-dependent effect of light on magnetic compass orientation in amphibians. Tadpoles trained and then tested under full-spectrum light displayed magnetic compass orientation that coincided with the trained shore-deep water axes of their training tanks. Conversely, tadpoles trained under long-wavelength (≥500 nm) light and tested under full-spectrum light, and tadpoles trained under full-spectrum light and tested under long-wavelength (≥500 nm) light, exhibited a 90° shift in magnetic compass orientation relative to the trained y-axis direction. Our results are consistent with earlier studies showing that the observed 90° shift in the direction of magnetic compass orientation under long-wavelength (≥500 nm) light is due to a direct effect of light on the underlying magnetoreception mechanism. These findings also show that wavelength-dependent effects of light do not compromise the function of the magnetic compass under a wide range of natural lighting conditions, presumably due to a large asymmetry in the relatively sensitivity of antagonistic short- and long-wavelength inputs to the light-dependent magnetic compass.
authors.affiliation: Departamento de Biología Animal, Universidad de Salamanca, Campus Miguel de Unamuno, Edificio de Farmacia 5ª planta, 37007 Salamanca, Spain. fjdiego@herpetologica.org
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Diego-Rasilla
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Luengo
authors.forename: John B
authors.initials: JB
authors.lastname: Phillips
mesh_terms: D000818:Animals; D008027:Light; D060526:Magnetic Fields; D009949:Orientation / Q000502:physiology*; D011896:Rana temporaria / Q000502:physiology*; D013998:Time Perception