Túngara Frogs Mating Calls Also Attract Predators
November 12, 2019
When the Túngara frog trills or calls (Physalaemus pustulosus), not only is it looking for a mate, it also attracts blood sucking midges that use the calls to hone in on an easy meal, according to researchers at Purdue University.
“We study how frogs communicate with one another, but also how their predators eavesdrop and exploit those systems,” Ximena Bernal, an associate professor of biological sciences at Purdue University said in a statement released by the university detailing her study. “The irony is that a lot of times the calls that female frogs prefer, bats and flies prefer too. The poor males just can’t win.”
The frogs have to make that call in order to mate, but it is a double-edged sword for them as midges and bats intercept those calls. But they change based on the environment they are in.
The frog calls in city environments differed from frog calls in the forest. The researchers moved 100 frogs from the city to the forest and found that the frogs changed their call in the forest so they wouldn’t attract the attention of the midges, and bats which preyed upon the amphibians. In the city, the frogs got more fanciful in their trilling as there was less chance of predation.
“This means that in the city, sexual selection is intensified, and natural selection is relaxed, which leads to males using more complex calls,” Bernal said. Bernal’s research found that midges were sensitive to light and noise pollution, and the din of city traffic hindered their ability to locate the frogs, and the city lights at night also made it difficult for the midges to find the frogs.
In the future, Bernal is hoping to publish data on the effects of the blood parasite that midges transfer to frogs when they bite them.