Discrimination of electric signals: Implications for electrocommunication in the African electric catfish Malapterurus electricus (Gmelin 1789) Siluroidei, Malapteruridae.
Item
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Title
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Discrimination of electric signals: Implications for electrocommunication in the African electric catfish Malapterurus electricus (Gmelin 1789) Siluroidei, Malapteruridae.
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Identifier
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AAI9618110
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identifier
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9618110
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Creator
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Van Wettering, John Richard.
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Contributor
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Adviser: Peter Moller
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Date
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1996
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Psychobiology | Biology, Zoology | Biology, Animal Physiology
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Abstract
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The strong electric organ discharge (EOD) of the African electric catfish, Malapterurus electricus, functions as part of the fish's predatory and defensive behavior. Like other siluriforms, these catfish also possess ampullary electroreceptors (small pit organs) that can detect direct current and low-frequency alternating current. This study examines the responsiveness of Malapterurus to artificially generated pulsed stimuli to explore the possibility that these catfish detect and recognize conspecific EODs.;Three experiments were conducted using a model electric catfish to deliver controlled electric stimuli to individual subjects. The first experiment was designed to explore Malapterurus' responsiveness to a range of stimulus pulse durations. Locomotor activity, sheltering, electrode contact, and EOD production were recorded in the presence of volleys of artificial pulses. Durations ranged from 0.375 to 6.0 ms including a condition mimicking the naturally occurring 1.5 ms pulse. Catfish did not respond differentially to these pulses.;A second experiment examined differential responding to patterns consisting of simulated EODs, including patterns mimicking defensive and predatory type volleys. These volleys were of short or long duration, and of either low- or high-frequency. Malapterurus did not discriminate between stimulus volleys based on either frequency or volley duration alone. The fish, however, were able to distinguish between defensive and predatory volleys based on naturally occurring combinations of these two parameters.;In the third experiment, subjects were tested for their response to stimuli of different amplitudes. Because the EOD amplitude of Malapterurus increases as the fish grow, and because Malapterurus does not discharge during conspecific encounters, it was hypothesized that EOD amplitude can provide information to conspecific competitors signalling size. Electric catfish withdrew and maintained their distance from a model generating EOD amplitudes greater than their own and approached a model generating relatively low amplitude stimuli.;Although the discharge of Malapterurus electricus is used as a powerful tool in predation, the present study has provided sufficient evidence for the EOD's role in intraspecific communication.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
