Antibiotics affect migratory restlessness orientation

Magnetoreception is a sense that allows the organism to perceive and act according to different parameters of the magnetic field. This magnetic sense plays a part in many fundamental processes in various living organisms. Much effort was expended in finding the ‘magnetic sensor’ in animals. While some experiments show a role of the ophthalmic nerve in magnetic sensing, others show that effects of light on processes in the retina are involved. According to these inconclusive and puzzling findings, the scientific community has yet to reach an agreement concerning the underlying mechanism behind animal magnetic sensing. Recently, the symbiotic magnetotaxis hypothesis has been forwarded as a mechanistic explanation for the phenomenon of animal magnetoreception. It suggests a symbiotic relationship between magnetotactic bacteria (MTB) and the navigating host. Here we show that in contrast to the control group, antibiotic treatment caused a lack of clear directionality in an Emlen funnel experiment. Accordingly, the antibiotics treatment group showed a significant increase in directional variance. This effect of antibiotics on behaviors associated with animal magnetic sensing is, to the best of our knowledge, the first experimental support of the symbiotic magnetotactic hypothesis.