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

Abstract

The evolutionary history of invasive species within their native range may involve key processes that allow them to colonize new habitats. Therefore, phylogeographic studies of invasive species within their native ranges are useful to understand invasion biology in an evolutionary context. Here we integrated classical and Bayesian phylogeographic methods using mitochondrial and nuclear DNA markers with a palaeodistribution modelling approach, to infer the phylogeographic history of the invasive ant Wasmannia auropunctata across its native distribution in South America. We discuss our results in the context of the recent establishment of this mostly tropical species in the Mediterranean region. Our Bayesian phylogeographic analysis suggests that the common ancestor of the two main clades of W. auropunctata occurred in central Brazil during the Pliocene. Clade A would have differentiated northward and clade B southward, followed by a secondary contact beginning about 380,000 years ago in central South America. There were differences in the most suitable habitats among clades when considering three distinct climatic periods, suggesting that genetic differentiation was accompanied by changes in niche requirements, clade A being a tropical lineage and clade B a subtropical and temperate lineage. Only clade B reached more southern latitudes, with a colder climate than that of northern South America. This is concordant with the adaptation of this originally tropical ant species to temperate climates prior to its successful establishment in the Mediterranean region. This study highlights the usefulness of exploring the evolutionary history of invasive species within their native ranges to better understand biological invasions.

A tale of swinger insects: Signatures of past sexuality between divergent lineages of a parthenogenetic weevil revealed by ribosomal intraindividual variation

“…In areas partially overlapping with the one identified in this work, the possible occurrence of a secondary contact between highly divergent clades has been reported for the Rufous-collared sparrow [ 48 ] and the little fire ant [ 49 ]. In addition, [ 50 ] suggested the co-existence of multiple cryptic species among 18 species of butterflies inhabiting this area, similar to what we found in a previous work for lineages I and II of N .…”

“…Lineages in suture zones diverging due to isolation in Pleistocene refugia were suggested to have concomitant expansion times rather than divergence times, these expansions having been taken place in early to mid-Holocene times [ 55 ], as is the case for N . cervinus [ 21 ] and the little fire ant [ 49 ]. This assumption provides some additional support for the existence of a suture zone in the area under consideration.…”

Combining niche shift and population genetic analyses predicts rapid phenotypic evolution during invasion

“…There is an emerging willingness to integrate genetic, experimental, and modeling approaches in understanding invasions. Some studies have combined genetic identification of source populations with niche shift models (e.g., Chefaoui & Varela‐Álvarez, ; Chifflet et al., ; Fitzpatrick, Weltzin, Sanders, & Dunn, ; Ikeda et al., ) or with estimates of phenotypic shifts (e.g., Agrawal et al., ; Bossdorf et al., ; Schrieber et al., ). Others have combined tests of phenotypic shifts with niche models (e.g., Dlugosch et al., ; Turner, Fréville, & Rieseberg, ; Wittmann, Barnes, Jerde, Jones, & Lodge, ), but more rarely are all three approaches used simultaneously (but see Rey et al., ; Hill, Chown, & Hoffmann, ).…”

Barcoding the butterflies of southern South America: Species delimitation efficacy, cryptic diversity and geographic patterns of divergence

“…While there is an ongoing debate around the evolutionary impacts of the habitat fragmentations caused by Pleistocene glaciations in the Brazilian Atlantic Forest, much less is known about the past status of this forest in Argentina. However, it was recently suggested that the Atlantic Forest in Misiones was a refuge during the Last Glacial Maximum for the fire ant Wasmannia auropunctata [ 71 ]. As well, two new forest refugia in Paraná and Santa Catarina, two Brazilian states bordering Misiones, have been recently proposed [ 69 ].…”