Some African fish signal their amorous intentions by exchanging bursts of electrical impulses, a new study has found.
Scientists describe this behavior as being somewhat similar to the courtship duets of songbirds.
According to the study, which has been reported by National Geographic, these fish produce weak electrical fields using specialized organs in their tails.
Until now, the love life of electric fish was largely a private matter, claims Carl Hopkins of Cornell University.
Hopkins and undergraduate Ryan Wong employed a variety of tricks, including sprinkling tanks with artificial rain, to simulate breeding-season conditions.
Using recording equipment and custom software, both observed the electrical signaling and physical behavior of the fish.
Wong, who described the whole sequence as "electrical duetting", said both males and females seemed to make specific "sounds" before, during, and after mating.
The signals aren't actually songs, because the fish sense them electrically rather than acoustically, Wong added.
Early biologists, including Charles Darwin, were puzzled by what function the faint electric fields could serve. Now, scientists know the fields are part of an "electric sense" used for both navigation and communication. They claim that the unusual sensory skill helps the fish thrive in murky streams of west Africa.
Previous work has shown that each electric fish species has a unique form of electrical discharge, like a fingerprint. In the new study, the researchers found that certain discharge patterns were associated with certain types of behavior.
Males produced more "rasp" and "medium burst" patterns when they were near females and during courtship, suggesting that the signals "advertise" the males' quality as mates. Females were found to create a "creak" pattern only during spawning, possibly to facilitate or signal the release of eggs.
After extended courtship interactions, the two sexes sometimes engaged in electrical "duets" of alternating rasps and bursts.
By studying the buzzes of electric fish, researchers hope to gain new insights into the evolution of animals' breeding behavior and communication.
The new study suggests that electrical signaling may have been shaped in part by sexual selection, the evolutionary process responsible for many animals' elaborate decorative features and courtship behaviors.