The frog Lithodytes lineatus (Anura: Leptodactylidae) uses chemical recognition to live in colonies of leaf-cutting ants of the genus Atta (Hymenoptera: Formicidae)

Abstract

Chemical-based mimicry and camouflage are known to be employed by invertebrate parasites of social insect colonies, but the use of this strategy by vertebrates to avoid being detected by social insects has received less attention. In this paper, we examine the hypothesis that frog Lithodytes lineatus has skin chemicals that imitate chemical recognition used by leaf-cutting ants of genus Atta. We show that individuals of Lithodytes lineatus were never attacked by the leaf-cutting ants of genus Atta, while 100 % of four other anuran species were. In addition, none of the ten individuals of frog Rhinella major coated with skin extracts of frog L. lineatus were attacked, whereas controls (coated with ultrapure water) were attacked on each occasion. Our results demonstrate that the skin of frog Lithodytes lineatus has chemicals that prevent the attack of both species of leaf-cutting ants, Atta laevigata and Atta sexdens. In order to reduce the risk of predation, some frog species engage in commensal or mutualistic relationships with invertebrates, but associations between frogs and ants are rarely reported in literature. We show that frog Lithodytes lineatus are not attacked by ants Atta laevigata and A. sexdens; however, other frog species are aggressively attacked. Our results suggest that the biomolecules present in the frog skin are capable of inhibiting the attack of ants, allowing coexistence. This is the first study reporting the possible mechanism for association between frog L. lineatus and ants of genus Atta.