Myrmecophagy in lizards: evolutionary and ecological implications.

Myrmecophagy is one of the most common dietary specializations among vertebrates. Ants are an important food resource for many lizard species. Here, we use a large dataset on ant consumption by lizards (345 species, 33 families) to explore evolutionary and ecological correlates of myrmecophagy across the evolutionary history of lizards. Based on literature and previous empirical work, we develop and test the following hypotheses about myrmecophagy: (i) it does not occur randomly across Squamata; it is correlated with (ii) foraging mode, (iii) habitat, (iv) body size, (v) aridity, and/or (vi) species range size. We found that ant ingestion is not distributed randomly in the phylogeny, with higher ingestion concentrated in some Iguania. Myrmecophagy also evolved in Lacertoidea and it is a derived trait with relatively recent origin. Foraging mode, habitat, body size, and aridity do not influence ant ingestion. Species with smaller range sizes show high variability in ant ingestion, whereas lizards with larger ranges tend to eat a lower proportion of ants. This result confirms the general ecological pattern that specialization is more common in narrowly distributed species. We suggest that future studies should also explore dietary specialization more broadly and provide a better taxonomic resolution of ant species in the diet of lizards. [ABSTRACT FROM AUTHOR]