MANAUS, Brazil, Oct. 20 (UPI) -- Most frogs and amphibians that get in the way of South America's leaf-cutting ants will end up bitten -- pestered until they vacate the ants' territory. But not Lithodytes lineatus, a small, slimy, yellow-striped frog from the Amazon.
As new research reveals, Lithodytes lineatus oozes a natural ant repellent through its skin. The chemical concoction tricks the ants into ignoring the frog.
"It helps the frog blend in, because it imitates the ants own chemical signals," André Barros, a scientist at the National Institute of Amazonian Research in Brazil, explained in a news release.
Chemical camouflage of this kind is relatively common among parasitic invertebrates, but rare among vertebrates. Of hundreds of species, only two other Amazonian frogs are known to cloak themselves in the scent of their would-be tormentors.
In lab experiments, researchers found Lithodytes lineatus were content to live among leaf-cutting ants, while similar frog species quickly bolted for the nearest exit when placed in close quarters with the insects.
When researchers coated related species with the skin extract of Lithodytes lineatus, ants declined to bite frogs they were previously willing to attack.
"Our results demonstrate that the skin of frog Lithodytes lineatus has chemicals that prevent the attack of two species of leaf-cutting ants," Barros said. "It therefore seems that Lithodytes lineatus has chemical skin compounds that are recognized by ants of genus Atta, which may allow for coexistence between ants and frogs."
Barros and his colleagues published their research in the journal Behavioral Ecology and Sociobiology.