On the Diversity of Electric Signals in a Community of Mormyrid Electric Fish in West Africa

SYNOPSIS. Communication through electric discharges is a rich and varied modality of social communication among mormyrid fishes of West Africa. Field studies permitted an analysis of the electric signals of over 20 species of Mormyridae living sympatrically in and near the Ivindo River of Gabon. Electric discharges can be classified according to their waveforms and can be shown to be species-specific in many cases. The waveform of the discharge is a signature which is a carrier for social communication signals. The paper asks: “Why is the signature, or carrier, adaptive?” An analysis points to competitive and cooperative forces in the evolution of electrical waveforms, not physical or habitat forces. Competition between species, as well as mutualistic interactions, appear important in explaining how electrical signatures are adaptive for: 1) channel privacy (noise immunity); 2) unique signals for species recognition ; and 3) electrolocation signals less vulnerable to jamming.