Orientation, Homing, and Navigation in Caribbean Spiny Lobsters
The Caribbean spiny lobster, Panulirus argus, is an active, migratory crustacean commonly found in coral reef ecosystems of the western Atlantic. For most of the year, spiny lobsters spend daylight hours inside coral reef crevices, emerging at night to forage over considerable areas before returning in nearly total darkness to the same den or to one of several others nearby. In some geographic areas, lobsters undergo an autumn migration in which they line up in immense, single-file lines and march offshore. Lobsters are also capable of homing to a specific den if displaced to an unfamiliar area. The ability to maintain consistent headings while migrating under water, and to move reliably even in darkness to specific targets such as dens, imply that lobsters possess a remarkable suite of orientation and navigation mechanisms.
Studies have revealed that lobsters have a well-developed magnetic compass sense that enables them to establish and maintain courses relative to the Earth’s magnetic field. Even more surprisingly, lobsters can derive positional information from the Earth’s magnetic field and use this to help them figure out their geographic location. This remarkable ability, known as a “magnetic map sense”, endows the lobsters with a sensitive navigational system rivaling that of sea turtles and salmon.
Precisely how lobsters and other animals detect magnetic fields is not known. One possibility is that crystals of the mineral magnetite form the basis of the magnetic sense. Magnetite is a magnetic iron oxide and crystals of magnetite will attempt to align with Earth’s magnetic field in much the same way that compass needles do. In one experiment, lobsters were subjected to strong magnetic pulses capable of altering the magnetic dipole moment of magnetite crystals. Such pulses were found to alter the direction that lobsters oriented, a finding consistent with the hypothesis that lobsters have magnetite-based magnetic receptors.
For a more detailed description of research on spiny lobster orientation and navigation, click here.
Boles, L. C. and K. J. Lohmann. 2003. True navigation and magnetic maps in spiny lobsters. Nature. 421: 60-63. [Download pdf] [New York Times] [National Geographic] [Science News]
Ernst, D. and K. J. Lohmann. 2016. Effect of magnetic pulses on Caribbean spiny lobsters: Implications for magnetoreception. Journal of Experimental Biology. 219: 1827-1832 doi:10.1242/jeb.136036 [Download pdf]
Lohmann, K. J. 1984. Magnetic remanence in the western Atlantic spiny lobster, Panulirus argus. Journal of Experimental Biology. 113: 29-41. [Download pdf]
Lohmann, K. J. and D. A. Ernst. 2014. The geomagnetic sense of crustaceans and its use in orientation and navigation. In: Crustacean Nervous Systems and their Control of Behavior (editors: C. D. Derby and M. Thiel), pp. 321-336. Oxford University Press: New York, New York. [Download pdf]
Lohmann, K. J., Pentcheff, N. D., Nevitt, G. A., Stetten, G., Zimmer-Faust, R. K., Jarrard, H. E., and L. C. Boles. 1995. Magnetic orientation of spiny lobsters in the ocean: experiments with undersea coil systems. Journal of Experimental Biology. 198: 2041-2048. [Download PDF]
The Caribbean spiny lobster Panulirus argus (photo from The Vibrant Sea)
For a more detailed series of web pages describing what is known about spiny lobster orientation, homing, and navigation, click here.