Communication in fish can be quite electric

Fish can use electric signals for different kind of communication. Photo courtesy of Photocase.com

We all know the impressive electric discharges of up to 500 volt used in the electric eel to catch prey or to defend itself against hapless swimmers. However, the so-called weakly electric fish uses their much more harmless discharges for other matters. It has been known for some time that weakly electric fish uses discharges as a means of electrolocation , whereby they can sense surrounding obstacles in murky water, similar to echolocation in bats. Recently, it was shown in one species of electric fish that it also uses these electric discharges as a mean of communication.

It has two ways of sending out electric discharges. Low frequency pulses are used by both sexes in response to conspecifics and are thought to function as aggressive or warning signals. High frequency pulses, however, are only used by the male in response to female-like electric signals and function as courtship signals.

Now researchers from Indiana University Bloomington and Emory University in America have, by playing recorded signals back to the fish, compared signals in different species of weakly electric fish and found different utilisation of the same signals. For instance in the common electric fish Apteronotus albifrons both males and females discharge high frequency pulses in response to both same-sex and different sex conspecifics and it is therefore unlikely that high frequency pulses in this species function as courtship signals. The different use of signals in weakly electric fish thus has the potential to teach us more about how different selection pressures can shape the evolution of    
the use and understanding of signals.

Source: Kolodziejski, J. A., Sanford, S. E. and Smoth, G. T. (2007). Stimulus frequency differentially affects chirping in two species of weakly electric fish: implications for the evolution of signal structure and function. Journal of Experimental Biology 210: 2501-2509.

Tag it:

?

Be first to comment this article

Only registered users can write comments.
Please login or register.

Powered by AkoComment Tweaked Special Edition