Magnetic compass orientation in insects
Animals from groups as diverse as mammals, insects, amphibians, birds, turtles and crustaceans have been shown to be capable of magnetosensitive orientation, meaning that they can sense and make use of magnetic fields for navigation purposes. We examine the possible presence of a magnetic compass in bumblebees by training Bombus terrestris workers to find rewards in ambient magnetic fields. The fields are produced by a magnetic coil system in a specially designated lab, where the bumblebee colony is kept inside the coil cube so that the magnetic environment of the bees can be controlled.
The exact mechanism of the magnetic compass in animals is not known, but there are two main hypotheses: either a light dependent one, or a compass depending on small magnetite particles. The establishment of a magnetic compass in bumblebees would make possible further research into the exact properties of the compass. It could also possibly shine new light on the drastic declines that are seen in many insect species, among them various bumblebees, as well as honeybees. Part of the decline could possibly, together with several other factors, be explained by disturbance of the magnetic compass by radio-frequency fields, affecting homing capabilities of foragers.