Forty years ago the Journal of Experimental Biology
published Hans Lissmann’s paper ‘On the function and
evolution of electric organs in fish’ (Lissmann, 1958) and his
companion paper on ‘The mechanisms of object location in
Gymnarchus niloticus and similar fish’ (Lissmann and Machin,
1958). It is fitting that the Journal should now publish a volume
reviewing our current knowledge of the neuroethology of
electroreception and electrogenesis, a field that can trace its
origin to Lissmann’s original papers. Lissmann and before him
Möhres (1957) suggested that social communication is an
important function for weak electric discharges in fish. Möhres
made some of the first playbacks of electric signals and evoked
responses from mormyrid fish. In the 1960s, Szabo, Bullock,
Bennett, Coates, Grundfest, Hagiwara and others explored
these exciting new peripheral sense organs, electric organs and
brain areas; but it was not until the work of Moller, Kramer,
Black-Cleworth, Westby, Kirschbaum, Hopkins and others
came out in the early 1970s that we started to glimpse the
diversity of electric communication signals and functions
(Black-Cleworth, 1970; Hopkins, 1972; Kirschbaum, 1995;
Kramer, 1995; Moller, 1995; Westby, 1974, 1975). Since then,
with more field studies, better information about sensory
processing in the brain and additional studies of the motor
control of electric signals (Kawasaki and Heiligenberg, 1988;
Kawasaki et al., 1988; Keller et al., 1991), we now know a
great deal about the neuroethology of electric communication,
perhaps more for electric fish than for any other sensory
modality except vision.
Still, there is much to learn. In this paper, I briefly outline
two design features of electric communication that make this
modality unique. By understanding them, we may hope to
understand more of how the electric modality has evolved and
how selection has influenced the structure and function of
signals and displays.
Design feature 1: limited signal range
The active space of an electric communication signal i