Evolutionary history of the little fire ant Wasmannia auropunctata before global invasion: inferring dispersal patterns, niche requirements, and past and present distribution within its native range

Authors: CHIFFLET, L - University Of Buenos Aires; RODRIGUERO, L - University Of Buenos Aires; CALCATERRA, L - Fuedei; REY, O - Inland Northwest Research Alliance, Inra; DINGHI, P - University Of Buenos Aires; BACCARO, J - Federal University Of Amazonas (UFAM); DE SOUZA, L - Instituto Nacional De Pesquisas Da Amazonia (INPA); Follett, Peter; CONFALLONIERI, V - University Of Buenos Aires

Submitted to: Journal of Evolutionary Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2016
Publication Date: 4/20/2016
Citation: Chifflet, L., Rodriguero, L., Calcaterra, L., Rey, O., Dinghi, P., Baccaro, J., De Souza, L., Follett, P.A., Confallonieri, V. 2016. Evolutionary history of the little fire ant Wasmannia auropunctata before global invasion: inferring dispersal patterns, niche requirements, and past and present distribution within its native range. Journal of Evolutionary Biology. 29(4):790-809.

Interpretive Summary: Phylogeographic methods and paleodistribution modeling was used to study the distribution of the invasive ant Wasmannia auropunctata within its native South America and recently invaded areas of the Mediterranean region. We generated Cytochrome Oxidase I sequences from 154 samples covering most of W.auropunctata native range, comprising individuals from the two major mitochondrial clades (A and B) within the species. We inferred that the common ancestor of these two clades was placed in central Brazil approximately 3.92 million years ago. Clade A differentiated northward and clade B southward, and a secondary contact process began approximately 380,000 years ago in central South America. The most suitable habitats, for three climatic periods analyzed, seem to differ between clades, suggesting that genetic differentiation might have been accompanied by a differentiation in niche requirements, clade A being a tropical lineage and clade B a subtropical and temperate lineage. Our results support that W.auropunctata is native in Argentina, and that only clade B reached higher southern latitudes, with colder climate than northern parts of South America. This is concordant with its later successful establishment in the Mediterranean region. The present study highlights the usefulness of exploring life history of invasive species within their native ranges to better understand invasion biology.

Technical Abstract: The evolutionary history of invasive species within their native range may involve key processes that allow them to colonize new habitats. We integrated classic and Bayesian phylogeographic methods with a paleodistribution modeling approach to study the demographic patterns that shaped the distribution of the invasive ant Wasmannia auropunctata within its native South America and discuss its native phylogeographic history with regard to its recent establishment in the Mediterranean region. We generated Cytochrome Oxidase I sequences from 154 samples covering most of W.auropunctata native range, comprising individuals from the two major mitochondrial clades (A and B) within the species. With a Bayesian phylogeographic analysis we inferred that the common ancestor of these two clades was placed in central Brazil approximately 3.92 million years ago. Clade A differentiated northward and clade B southward, and a secondary contact process began approximately 380,000 years ago in central South America. The most suitable habitats, for three climatic periods analyzed, seem to differ between clades, suggesting that genetic differentiation might have been accompanied by a differentiation in niche requirements, clade A being a tropical lineage and clade B a subtropical and temperate lineage. Our results support that W.auropunctata is native in Argentina, and that only clade B reached higher southern latitudes, with colder climate than northern parts of South America. This is concordant with its later successful establishment in the Mediterranean region. The present study highlights the usefulness of exploring life history of invasive species within their native ranges to better understand invasion biology.