Island-like divergence on Florida’s sand ridges – the case of a trap-jaw ant

Florida’s inland ridges originated as sand islands at a time when sea levels were significantly higher than they are now. These ridges (some up to 100 miles long) are home to orange trees, but also endemic animals like the charismatic trap-jaw ant Odontomachus relictus. This ant occurs on only two of these sand ridges and lives in sand hill scrub habitat. Here, I present preliminarily data from sampling populations on each ridge to test the hypothesis of species divergence between ridges using behavioral, morphological, and genetic data. Behavioral assays indicate a striking pattern of non-aggression within and aggression between clusters on each ridge. Phylogenetic analysis shows a significant divergence between ridges (but not within). Morphology shows no consistent inter-ridge differentiation. Collectively, these data suggest differentiation of ridge populations. Given that many of the species found on the ridges are even less vagile than O. relictus, cryptic species, many of them likely in need of conservation, may be common on each of the ridges.