Meeting Abstract
How animals detect Earth’s magnetic field remains a long-standing mystery of sensory biology. The ‘magnetite hypothesis’ proposes that the geomagnetic field exerts torque on tiny magnetite crystals, which in turn are connected to the nervous system and provide the physical basis for the magnetic sense. In principle, a strong magnetic pulse might remagnetize permanently magnetic minerals within an animal, thus potentially altering magnetoreceptors based on magnetite. The Caribbean spiny lobster, Panulirus argus, has an impressive magnetic sense and is the only invertebrate known to derive both directional and positional information from the geomagnetic field. Previous studies revealed that magnetic material is present in this species, and a magnetic pulse alters lobster orientation, suggesting that lobster magnetoreception is at least partly based on magnetite. However, little is known about the effect of a strong magnetic pulse on the central nervous system (CNS) of spiny lobsters or any other animal. To investigate the effect of a magnetic pulse on the CNS and identify genes associated with magnetoreception pathways, we subjected lobsters to either: (1) a magnetic pulse oriented antiparallel to the horizontal component of the geomagnetic field; or (2) a sham pulse, in which lobsters were handled identically but not pulsed. RNA sequencing was then used to examine gene expression in the brain, subesophageal ganglion, and thoracic ganglia. In all three tissues, numerous genes were differentially expressed, providing novel insights into how a magnetic pulse affects nervous tissue and the putative molecular mechanisms that underlie lobster magnetoreception.
