The Metabolic Cost of Electric Signalling in Weakly Electric Fish

Abstract

Wave-type weakly electric fish emit a highly regular electric discharge using a specialized electric organ. This electric organ discharge (EOD) forms the basis for an electric sense used for navigation, prey detection and communication. The metabolic cost of the EOD is not fully understood, but recent research suggests that it constitutes a significant portion of the fish's energy budget. In the current study, manipulation of metabolic rate via exposure to hypoxia did not significantly alter EOD frequency. Changes in metabolic rate through swimming resulted in EOD frequency increase. To manipulate EOD frequency directly in individual fish, the jamming avoidance response (JAR) and long term frequency elevation (LTFE) were used. EOD frequency elevation and jamming stimulation resulted in an increased M˙O2 possibly associated with increases in sensory processing. Taken together, these data indicate that electric signalling in wave-type weakly electric fish is a not a major contributor to whole-animal energetic cost.