Meeting Abstract
Although evidence for magnetic orientation in animals is plentiful, little is known about how animals detect magnetic fields. One hypothesis is that crystals of the mineral magnetite provide the physical basis for magnetoreception. When magnetite crystals attempt to align with Earth’s magnetic field, they might activate stretch receptors or hair cells, thus transducing magnetic information to the nervous system. Brief, strong magnetic pulses capable of remagnetizing magnetite are known to alter the orientation of several animals capable of magnetoreception. Magnetic material has been detected in the Caribbean spiny lobster (Panulirus argus), the only invertebrate known to possess both a magnetic compass and magnetic map. Furthermore, in laboratory experiments, the orientation of lobsters exposed to a magnetic pulse was significantly altered compared to control lobsters. To determine whether a magnetic pulse also affects lobster behavior in the field, lobsters were captured on a patch reef and either: (1) exposed to a magnetic pulse oriented antiparallel to the geomagnetic field; or (2) handled but not exposed to a pulse. Each lobster was then equipped with an acoustic transmitter and released back on the patch reef, which was surrounded by an array of acoustic receivers. Results suggest that lobsters exposed to a magnetic pulse were more likely to rapidly emigrate from the home reef, whereas control lobsters typically remained on the reef. These findings provide additional evidence that lobsters are sensitive to magnetic stimuli and are consistent with the hypothesis that the mechanism underlying magnetoreception involves magnetite.
