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On the electrodetection threshold of aquatic vertebrates with ampullary or mucous gland electroreceptor organs
Author(s) -
Peters Rob C.,
Eeuwes Lonneke B. M.,
Bretschneider Franklin
Publication year - 2007
Publication title -
biological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.993
H-Index - 165
eISSN - 1469-185X
pISSN - 1464-7931
DOI - 10.1111/j.1469-185x.2007.00015.x
Subject(s) - electroreception , pelagic zone , biology , earth's magnetic field , benthic zone , stimulus (psychology) , sensory system , escape response , electric fish , anatomy , zoology , physics , fish <actinopterygii> , ecology , fishery , neuroscience , magnetic field , psychology , quantum mechanics , psychotherapist
Abstract Reinterpretation of research on the electric sense in aquatic organisms with ampullary organs results in the following conclusions. The detection limit of limnic vertebrates with ampullary organs is 1 μVcm −1 , and of marine fish is 20 nVcm −1 . Angular movements are essential for stimulation of the ampullary system in uniform d.c. fields. Angular movements in the geomagnetic field also generate induction voltages, which exceed the 20 nVcm −1 limit in marine fish. As a result, marine electrosensitive fish are sensitive to motion in the geomagnetic field, whereas limnic fish are not. Angular swimming movements generate a.c. stimuli, which act like the noise in a stochastic resonance system, and result in a detection threshold in marine organisms as low as 1 nVcm −1 . Fish in the benthic space are exposed to stronger electric stimuli than fish in the pelagic space. Benthic fish scan the orientation plane for the maximum potential difference with their raster of electroreceptor organs, in order to locate bioelectric prey. This behaviour explains why the detection threshold does not depend on fish size. Pelagic marine fish are mainly exposed to electric fields caused by movements in the geomagnetic field. The straight orientation courses found in certain shark species might indicate that the electric sense functions as a simple bisensor system. Symmetrical stimulation of the sensory raster would provide an easy way to keep a straight course with respect to a far‐field stimulus. The same neural mechanism would be effective in the location of a bioelectric prey generating a near‐field stimulus. The response criteria in conditioning experiments and in experiments with spontaneous reactions are discussed.