South America is home to over 200 species of electric fish. They’re less familiar than their cousins, electric eels, but they are no less fascinating to UMass Boston Professor of Biology Luis De León, who recently received a $118,000 grant from National Secretariat for Technology and Innovation of Panama to study the fish.
“I’m originally from Panama, and I grew up surrounded by nature,” De León said. “When I was very small, I was curious about all this diversity, and how it came about.”
Electric fish in Panama are relatively young in evolutionary terms. They came on the scene about 3 million years ago, following the formation of the land bridge between North and South America. De León wants to figure out what factors led to their diversification since then. Each species of electric fish emits a unique electric field that helps it to communicate and hunt for prey. Since these fish are nocturnal and often live in murky waters, they need to use these electrical pulses to navigate their environment.
“It’s analogous to bats,” De León said. “The fish have specialized cells in their muscles that emit electric signals into the environment. The fish is able to detect objects in its environment when the signal is disrupted.”
What scientists don’t know is how, or why, each species uses a different electrical frequency. De León plans to connect these unique signals to genetic data. Previous research has shown that female fish like males with stronger, higher frequencies, but predators can detect these stronger signals. To test how important these signals are in mate choice, De León will bring fish into the lab, and see whether they respond to different frequencies. De León also wants to determine if the electrical output impacts the fish’s microbiome. He postulates that different signal frequencies might allow different microbes to thrive.
De León is also interested in the big picture of how new electric fish species come into being. De León’s future research will focus on groups of fish that colonize new geographic areas, and as a result of their isolation could develop different traits from primary fish populations. Ultimately, De León hopes to contribute to a deeper understanding of the processes that drive evolution in diverse tropical environments.
“Natural selection and evolution don’t have an ultimate goal,” he said. But through his research, De León hopes to trace evolution’s path more clearly.