Evolutionary History of promiscuous Chthonolasius ants

Multidisciplinary studies in evolutionary biology are often challenged by incongruity between the results of single disciplines. No comprehensive guideline exists for the resolution of such inconsistencies. They are mostly due to evolutionary processes which differently affect the markers of choice. The ant subgenus Chthonolasius comprises thirteen western Palearctic species. Recently, Chthonolasius ants were shown to sustain promiscuity as a regular reproduction strategy termed "social cleptogamy": In the absence of conspecific males, alate gynes mate with heterospecific males. Generally the heterospecific partner of the queen is excluded from reproduction, because only the males - which exclusively carry subsets of their mothers` genomes in ants - appear to be fertile among the hybrid offspring. It is conceivable, however, that at least sporadically fertile hybrid gynes are produced. Thus Chthonolasius genomes can be hypothesized to harbor elements of heterospecific genomes, a situation which would blur phylogenetic reconstruction. Social cleptogamy as displayed by Chthonolasius ants has not been analysed by modern molecular means so far. Own preliminary results revealed major incongruence between DNA and morphology-based trees. The goal of the project is to resolve the phylogeny of western Palearctic Chthonolasius and to unravel the causes of data incongruity. After an examination of the species delimitations currently suggested by morphology I will try to establish a robust supra-specific phylogeny of the recognized species. I propose a multidisciplinary approach utilizing the mitochondrial DNA marker COI, the nuclear DNA marker wingless, and morphological data. Twelve evolutionary scenarios will be balanced, which could, singly or combined, cause data incongruence in Chthonolasius. Data from the different sources will be analyzed independently by means of various reconstruction methods. Once maximum resolution of incongruities and recognition of the underlying evolutionary patterns is achieved, established methods of combined analysis will be applied. The results of the integrative analysis should facilitate a taxonomic revision and will help to refine the methodology of the integrative approach to species delimitation and phylogenetic reconstruction in the face of genome invasions. This study will yield the basis for a sound evolutionary history integrating phylogeny with knowledge on bionomics, ecology and biogeography. Questions to be answered include whether genome integrity is warranted despite frequent hybridization, whether social cleptogamy constitutes an ancient trait in the subgenus, and whether hybridization is a possible speciation mechanism in Chthonolasius.