by Rideeta Raquib ’19

Several species, such as the Lutjanus bohar fish species, have the ability to camouflage themselves to avoid predators. This allows them to have a selective advantage in their respective environments compared to other species. Dr. Andre de Lima Barros, from the National Institute of the Amazonian Research in Brazil, hypothesized that Lithodytes lineatus, a species of frog prominent in the Amazon region, are able to protect themselves from leaf cutting ant species called Atta. Lithodytes lineatus have chemicals in their skin that are able to imitate chemical recognition abilities that are present in these ants.

Ten individuals of Lithodytes lineatus, collected from Ducke, Madeira, and Jace Paraná, were placed with two other frog species, Adenomera femoralis and Adenomera picta, in a glass tube. The prominent leaf-eating ant colonies included the Atta sexdens colonies in Jaca Paraná and Ducke, as well as the Atta laevigata colony in Madeira. Individuals of Adenomera or L. lineatus were positioned near the entrances of the nests, whereas the Lithodytes lineatus and the other Adenomeria species were each exposed to the ants for ten minutes. Lithodytes lineatus did not attempt to escape, but the four other types of frogs were constantly attacked by the ants and were trying to climb out of the glass tube. After the ten minute duration, the number of ants attached to their skin was counted. A second set of studies was run, where twenty Rhinella frogs were exposed to the ants. Out of the sample, ten frogs were covered in Lithodytes lineatus skin, and they remained safe from the ants. Similar to the first test, each frog was placed near Atta nests, and after five minutes, the number of ants attacking the skin was calculated to yield results that proved the ants refrained from attacking the Rhinella frogs covered with the Lithodytes lineatus skin extracts.

Overall the study conveys that the frog species, Lithodytes lineatus, have chemical properties in their skin that are resistant to leaf cutting ant species, Atta laevigata and Atta sexdens. The results will enable scientists to receive an insight regarding evolution within the frog species, analyze survival strategies that promote reproduction and biodiversity, and discover whether the chemicals present in the skin of Lithodytes lineatus could be transformed into an anti-repellent for humans.

References:

1. A.d.L Barros, et al., 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). doi: 10.1007/s00265-016-2223-y.
2. Image retrieved from: http://www.chrisgillette.com/Nature/Peruvian-Amazon-2009/i-MxnqFcJ