The orientation of earthworms is influenced by magnetic fields

Abstract

Earth has a natural magnetic field that many animals use for orientation and navigation. With the development of technology,these natural systems have been exposed to high levels of man-made electromagnetism from the heavy usage of electric devices. Thisstudy aims to understand the possible effects of artificial magnetic fields on the behavioral responses of the earthworm, which is used inthis study as a model organism in laboratory conditions. The 3 experimental groups, each composed of 20 earthworms, were exposed to190–520 μT magnetic fields using a 1.5 V current for 1-h durations in a wire-wrapped vivarium. The experimental and control groupswere kept in similar conditions. A camera recorded the positions of the earthworms every 5 min. The angles, in terms of the mean vectorof each earthworm’s position beginning in the center of the vivarium, were documented using the Adobe Photoshop CS6 program. Themean vectors and angles of different experimental designs and controls were compared using circular statistics. The orientations ofthe earthworms in the control (261.4° ± 101.6°) and experimental (251.2° ± 94.1°) groups were statistically different (P < 0.005), and adeviation of approximately 10° to the east was observed for the experimental group in comparison to the control group.