Tag Archives: The Pennsylvania State University

Croaking Cuban frogs Create Competition in South Florida

3 Jun
Cuban Tree Frog. Photo courtesy of www.floridagardener.com

Cuban Tree Frog. Photo courtesy of http://www.floridagardener.com

Southern Florida, particularly the more metropolitan areas such as Miami and Ft. Lauderdale are definitely not known for being quiet areas. The constant honking of horns, people yelling in multiple languages and bold headlines of bizarre news events make South Florida a melting pot of noise.

While I lived there, I would often here screaming arguments ending in “go back where you came from” when cultures clashed. Scientists have found that humans may not be the only ones participating in the battle of “who gets the last word.”

Native tree frogs may be amping up their mating calls to be able to be heard over the invasive Cuban tree frogs that arrived to the state in the 1930s. The Cuban tree frogs likely ended up in Florida as stowaways in shipping crates.

Ecologist Jennifer Tennessen, a graduate student at The Pennsylvania State University, and her colleagues recorded the calls of the Cuban tree frog (Osteopilus septentrionalis) to see how they affected two native species of tree frogs: green tree frogs and pine woods tree frogs.

“We predicted that Cuban tree frog chorusing would interfere most with native tree frogs whose acoustic behaviors were similar,” Tennessen said, “and that these would be the most likely candidates to modify their acoustic behavior to avoid interference.”

Her prediction was right. After playing recordings of the Cuban tree frogs, green tree frogs (who have a call similar to Cuban tree frogs) in Everglades National Park doubled their number of calls per minute. This change did not occur in pine woods tree frogs and researchers predict this is because their call is more easily distinguishable from the others.

“By increasing their call rate, green tree frogs may be able to increase the likelihood that potential mates can detect them amidst the noise,” Tennessen said. “This response, however, likely comes at the cost of requiring additional energy, which could be detrimental as it may divert energy away from other important functions like digestion and immune function.”

She also explained that because the green tree frogs are doubling their call rate, predators may find them more easily. The competing call of the Cuban tree frog could also disrupt the soundscape of other organisms who rely on sound for survival.