Among mormyrid fish, conversation is literally buzzing. Using specialized electricity-emitting organs in their tails, these African natives string together short shocks into a primitive analog to Morse code, says study coauthor Bruce Carlson, a neuroecologist at Washington University in St. Louis.
A scientist who studies the small, silver elephantfish may have stumbled on the key to speciation, the process that allows one species to evolve into two or more. And it’s all about developing new sensory perceptions.
The Mormyridae, a family of African fishes that communicate by means of weak electric discharges, has more than 200 species. New work shows the fishes evolved a complex signal-processing brain before a burst of speciation. Together with other evidence the finding suggests brain evolution triggered diversification.
The sensory pathway that detects and analyzes the electric discharges in the Mormyridae had been well studied, but only in two or three species, Carlson says, and the family has more than 200. Given its diversity Carlson asked whether changes in electrical communication might have influenced rates of speciation.
Carlson, PhD, assistant professor of biology in Arts & Sciences, is studying the African family of weakly electric fishes called the Mormyridae, or mormyrids.
Each fish in this family has an electric signal distinctive to its species, but also, to its sex, dominance status and even its individual identity.
Bruce Carlson stands next to a fish tank in his lab, holding a putty colored Radio Shack amplifier connected to two wires whose insulation has been stripped. At the bottom of the tank a nondescript little fish lurks in a sawed-off section of PVC pipe.
The rivers and lakes of Africa are filled with conversations that you cannot hear or take part in. These chats are conducted by fishes called mormyrids or elephantfishes, which can produce and sense electric fields.
Bigger brain regions caused a ‘big bang’ in the evolution of African electric fish, new research has shown.
Carlson, PhD, assistant professor of biology in Arts & Sciences, is studying the African family of weakly electric fishes called the Mormyridae, or mormyrids.
Our 2009 paper Temporal-Pattern Decoding in Electric Fish in the Journal of Neuroscience was featured in ‘This Week in the Journal’
Our 2004 paper The Who’s Who Signal in Electric Fish in the Journal of Neuroscience was featured in ‘This Week in the Journal’
Our 2004 paper in The Journal of Experimental Biology was featured in ‘Inside JEB’ in an article by Kathryn Phillips.