To get a sex partner, both males and females employ a lot of signals, from pheromones and songs to gifts and elaborated dances or coats. But some of the methods look as if taken from fiction movies: electric serenades! A Cornell research team has found that the African electric fish couples not only employ specific electrical signals to attract a mate, but also engage in a kind of dueling "electric duet."

This is the first time when electrical and behavioral displays were observed in breeding and non-breeding Brienomyrus brachyistius, a type of mormyrid electric fish, which emit weak electric fields from a batterylike organ in their tails to detect their environment and signal their species, sex and social status with other fish. This was for the first time when researchers saw how the electrical signals are involved in sexual behavior.

"Our study provides strong evidence that the 'rasp' [a certain electric signal] is a male advertisement call during courtship in this species. The males also serenade females with lower frequency 'creaks'." said co-author Ryan Wong who conducted the study as an undergraduate for his senior honors thesis, being now a Ph.D. student at the University of Texas in Austin.

The team developed custom software that allowed the separation and documentation of the electrical pulses based on sex. The researchers captured on video four pair of mating mormyrids (an astonishing accomplishment, as the species rarely breeds successfully in captivity) and detected 9 common motor displays and 11 specific pulse sequences linked to courtship and mating.
"Knowing the electrical and motor patterns during courtship allows for further exploration of such topics as mate choice and neural basis of pattern generation in these fish. The next step in the research will be to decode the fish transmissions and unravel their meaning," explained lead researcher Carl D. Hopkins, professor of neurobiology and behavior.