The Parietal Eye of Lizards (Pogona vitticeps) Needs Light at a Wavelength Lower than 580 nm to Activate Light-Dependent Magnetoreception
Institute for Advancement of Clinical and Translational Science (iACT), Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
Translational Research Center for Medical Innovation, 1-5-4 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
Received: 14 February 2020 / Revised: 20 February 2020 / Accepted: 6 March 2020 / Published: 15 March 2020
(This article belongs to the Section Wildlife
In this study, the author sought to identify the wavelength of light that activates light-dependent magnetoreception. Pogona vitticeps lizards were randomly divided into two groups. In both groups, small round light-absorbing filters were fixed to the back of each lizard’s head, to block light of wavelengths lower than 580 nm. The electromagnetic field group received 12 h of systemic exposure per day to an electromagnetic field at an extremely low frequency (light period), whereas the control group did not. For each animal, the average number of tail lifts per day was determined. No significant difference between the two groups, neither for the average ratio of the number of tail lifts on test days to the baseline value nor the average increase in the number of tail lifts on test days minus the baseline value (p = 0.41 and p = 0.67, respectively). The results of this experiment suggest that light-dependent magnetoreception in P. vitticeps only occurs when the light hitting the parietal eye is of a wavelength lower than 580 nm.