Electric Signals

Weakly electric fishes generate low-amplitude electric signals to navigate and to communicate. These capacities have required the coevolution of electric organs for signal production and sensory pathways in the brain for signal detection. Electric signals exhibit a wide range of diversity across the hundreds of species of weakly electric fishes. Some species generate pulse-type signals, in which each electric pulse is followed by a variable period of silence. Other species generate wave-type signals, in which each pulse is followed immediately by the next pulse such that the signal is quasi-sinusoidal. Electric signal waveform often contains identifying information about the sender, and rapid, transient temporal or spectral modulation conveys information about behavioral state. Since the discovery of the weak electric sense almost 70 years ago, scientists have learned a remarkable amount about electric signal generation, detection, and contribution to natural behaviors. Here we highlight these topics, with extra emphasis on mechanisms of signal production, neural coding, and evolutionary ecology.