%0 Journal Article %T A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture %A Munetoshi Maruyama %A Florian M Steiner %A Christian Stauffer %A Toshiharu Akino %A Ross H Crozier %A Birgit C Schlick-Steiner %J BMC Evolutionary Biology %D 2008 %I BioMed Central %R 10.1186/1471-2148-8-237 %X We recovered two well supported major lineages. One includes Acanthomyops, Austrolasius, Chthonolasius, and Lasius pallitarsis, which we confirm to represent a seventh subgenus, the other clade contains Dendrolasius, and Lasius sensu stricto. The subgenus Cautolasius, displaying neither social parasitism nor fungiculture, probably belongs to the second clade, but its phylogenetic position is not resolved at the cutoff values of node support we apply. Possible causes for previous problems with reconstructing the Lasius phylogeny include use of other reconstruction techniques, possibly more prone to instabilities in some instances, and the inclusion of phylogenetically distorting characters.By establishing an updated phylogenetic framework, our study provides the basis for a later formal taxonomic revision of subgenera and for studying the evolution of various ecologically and sociobiologically relevant traits of Lasius, although there is need for future studies to include nuclear genes and additional samples from the Nearctic. Both social parasitism and fungiculture evolved twice in Lasius, once in each major lineage, which opens up new opportunities for comparative analyses. The repeated evolution of social parasitism has been established for other groups of ants, though not for temporary social parasitism as found in Lasius. For fungiculture, the independent emergence twice in a monophyletic group marks a novel scenario in ants. We present alternative hypotheses for the evolution of both traits, with one of each involving loss of the trait. Though less likely for both traits than later evolution without reversal, we consider reversal as sufficiently plausible to merit independent testing.Ants of the Northern-hemispheric, temperate genus Lasius (Formicinae) are scientifically significant, in terms of relative abundance and ecological impact [1,2]. Because of the diversity of their signal and defense chemistry, Lasius ants are organisms widely used in chemical ecolog %U http://www.biomedcentral.com/1471-2148/8/237