Infection in Native Populations of the Invasive Tawny Crazy Ant .

Antagonistic interactions can affect population growth and dispersal of an invasive species. are intracellular endosymbiont bacteria that infect arthropod and nematode hosts and are able to manipulate reproduction, which in some cases leads to cocladogenesis. Moreover, the presence of the strictly maternally transferred in a population can indirectly induce selective sweeps on the hosts' mitochondria. Ants have a infection rate of about 34%, which makes phylogenetic studies using mitochondrial markers vulnerable of being confounded by the effect of the endosymbiont. is an invasive ant native to South America, considered a pest in the United States. Its distribution and biology are poorly known in its native range, and the taxonomic identity of this and its closely related species, , has only recently been understood with the aid of molecular phylogenies. Aiming at estimating robust phylogenetic relationships of in its native range, we investigated the presence and pattern of infection in populations of from Argentina, part of its native range, to account for its possible effect on the host population structure. Using the gene, 30 nests of and four from sympatric species were screened for the presence of . We sequenced the MLST genes, the highly variable gene , as well as , a novel target gene for which new primers were designed. Phylogeny of the ants was estimated using mtDNA (COI). We found supergroup A strains infecting 73% of nests and two nests of sp. 1. phylogenetic tree inferred with MLST genes is partially congruent with the host phylogeny topology, with the exception of a lineage of strains shared by ants from different clades. Furthermore, by comparing with sequences infecting other ants, we found that the strains infecting different clades are not monophyletic. Our findings suggest there are three recent independent horizontally transmitted infections in , and we found no evidence of influence of in the host mtDNA based phylogeny.