A team of researchers has found that a South American frog species uses chemical camouflage to live among aggressive leaf-cutting ants. The frog, which dwells in the Amazon rainforest, mimics the ants’ own chemical signals to avoid being attacked. The details are in a paper that was just published in the journal Behavioral Ecology and Sociobiology.
Chemical-based mimicry is common among invertebrates, especially parasites. The tactic is rarely seen in vertebrates, however. Researchers suspected that Lithodytes lineatus frogs may be using some form of chemical camouflage to avoid ant bites. Leaf-cutting ants (Atta laevigata and Atta sexdens) are highly aggressive and attack all frogs except L.lineatus. L.lineatus frogs, which are small amphibians with bright yellow stripes, live peacefully with the ants in their rainforest home.
Researchers from the National Institute of Amazonian Research in Brazil studied the frogs to find out if chemical mimicry was involved. They found that while leaf-cutting ants normally attack another local frog, Rhinella major, the frog was protected if coated in the same skin extracts as L. lineatus. The chemicals found on the frog’s skin appeared to mimic signals that leaf-cutting ants use for communication. This allows L. lineatus to blend in and avoid attacks. Since L. lineatus is the only frog species that can live with the ants, they don’t have to deal with much competition and benefit from humid microclimates created by the anthills.
There are only three frog species known to use chemical mimicry, including L. lineatus. There are many benefits to this kind of camouflage and it allows L. lineatus to blend in with dangerous leaf-cutting ants. The ants, which normally attack and prey on frogs, leave L. lineatus frogs alone. This unusual coexistence provides the frogs with a safe, humid environment. The exact chemicals used for this mimicry have yet to be identified.
André de Lima Barros, Jorge Luis López-Lozano, Albertina Pimentel Lima. The frog Lithodytes lineatus (Anura: Leptodactylidae) uses chemical recognition to live in colonies of leaf-cutting ants of the genus Atta (Hymenoptera: Formicidae). Behavioral Ecology and Sociobiology (2016).