Lizards respond to an extremely low-frequency electromagnetic field

Abstract

SUMMARYAnimals from a wide range of taxa have been shown to possess magnetic sense and use magnetic compasses to orient; however, there is no information in the literature on whether lizards have either of these abilities. In this study, we investigated the behavioral responses of a diurnal agamid lizard (Pogona vitticeps) to a sinusoidal extremely low-frequency electromagnetic field (ELF-EMF; 6 and 8Hz, peak magnetic field 2.6T, peak electric field 10 Vm -1 ). Fourteen adult lizards were divided randomly into two groups (the EMF and control groups; each group had three males and four females). The EMF group received whole-body exposure to ELF-EMF and the control group did not. Lizards in the EMF group were exposed to ELF-EMF for 12h per day (during the light period). The number of tail lifts was monitored beginning 3days before exposure and ending after 5 days of exposure. For each individual, the average number of tail lifts per day was calculated. The average number of tail lifts per individual per day was greater in the EMF group than in the control group (20.7±6.3 and 9.1±4.5 tail lifts, respectively, N7 each, P0.02). We confirmed the reproducibility of this response by a cross-over trial. These results suggest that at least some lizards are able to perceive ELF-EMFs. Furthermore, when the parietal eye of the lizards was covered with a small round aluminum 'cap' which could block light, the tail-lifting response to ELF-EMF disappeared. Our experiments suggest that (1) lizards perceive EMFs and (2) the parietal eye may be involved in light-dependent magnetoreceptive responses.

Biology and Diseases of Reptiles

“…Certain boid species have pits scattered in the infralabial and supralabial scales. LABORATORY ANIMAL MEDICINE Many lizard species have a parietal or 'third' eye, which contains photoreceptors that may permit enhanced detection at dawn and dusk (Solessio and Engbretson, 1993) and light dependent magnetoreceptive and orientation responses (Foà et al, 2009;Nishimura et al, 2010). In pit vipers, coordination of the infrared sensing mechanism of pit organ and ocular function is essential for prey targeting (Chen et al, 2012).…”

A physical mechanism of magnetoreception: Extension and analysis

“…The effect of weak magnetic fields (MFs) on biological systems is now well established. Five research areas have provided extensive data: a variety of laboratory studies [Jeong et al, 2000;Del Seppia et al, 2007;Nishimura et al, 2010;Prato et al, 2013], the magnetic navigation of some migratory species [Wu and Dickman, 2012;Engels et al, 2014], observational studies [Burda et al, 2009], epidemiological observations [Lewis et al, 2016], and geomagnetic biospheric correlations [Ossenkopp et al, 1983;Cornelissen et al, 2002;Breus et al, 2015]. The last three areas do not prove a direct biological action of very weak variable MFs, but they also do not exclude it.…”

The Parietal Eye of Lizards (Pogona vitticeps) Needs Light at a Wavelength Lower than 580 nm to Activate Light-Dependent Magnetoreception

“…In our previous studies [3,4], we focused on tail-lifting behavior of lizards, including the agamid lizard Pogona vitticeps [5]. The lizard Leiocephalus carinatus shows tail-curling behavior during intraspecific agonistic encounters and courtship [6,7].…”

“…The lizard Leiocephalus carinatus shows tail-curling behavior during intraspecific agonistic encounters and courtship [6,7]. We discovered that exposure to electromagnetic fields (EMFs) of extremely low frequency (6 and 8 Hz; peak magnetic and electric fields, 2.6 µT and 10 V/m, respectively) increased the number of tail-lifts by lizards [3]. Additionally, when a small, round aluminum "cap" was employed to shield the parietal eye of each lizard, the reaction to the EMF disappeared.…”