ИСТИНА

The ability to orient using magnetic compass initially shown in birds, was subsequently reported in other animals, amphibians including. Migrating marsh frogs were shown to follow direction between the breeding and the wintering site and to obtain directional information from the Earth’s magnetic field (MF). Previously we demonstrated the effect of MF direction effects on the photoresponses of bird’s retina, whose magnetic compass is suggestively located in the retina. Here we discuss the attempt of similar research for the frog’s retina. Marsh frogs were captured in southern Russia in autumn and placed in conditions that mimic wintering. After several months, animals were stimulated for reproductive activity and electroretinograms (ERGs) were recorded from isolated retinas. The ERG’s responses to flashes of red and blue light were tested under two direction of MF: 1) natural for habitat of this population and 2) MF with inverse inclination. Than, a- and b-waves of ERGs were compared for different conditions. We revealed differences in amplitudes of a-waves of ERG in response to flashes of only blue light under different directions of MF. Preliminarily, our data could suggest that magnetic compass in frogs is photosensitive and localized in the retina.