Análises moleculares das formigas lava-pés (Solenopsis spp.) (Hymenoptera : Formicidae) e da presença da endobactéria Wolbachia

Abstract

Listen

Translate article

The genus Solenopsis has a cosmopolitan distribution, but species of S. saevissima group are native from South America and include the known fire ant. They were accidentally introduced in several countries of the world. In Brazil they have wide distribution with preference for areas of human activity. Ants are highly aggressive and responsible for accidents that can lead to anaphylactic shock and death. The ants have different associations with other organisms, including bacteria endosymbionts such as Wolbachia, intracellular bacteria that also infect the ants of the Solenopsis genus. In this study, we sought to characterize the populations of fire ants (Solenopsis spp.) in a wide area of Brazil, analyzing the relationship of these populations and inferring their phylogeny. Furthermore, we investigated the presence, frequency and distribution of the endosymbiont Wolbachia in those populations of Solenopsis spp. in Brazil. The characterization of fire ants was based on analysis of the cytochrome oxidase I gene and on phylogenetic studies. It was observed that there were complete geographical coherence and polyphyly for the species S. invicta and S.saevissima, which clearly demonstrate the diversity of this genus of ants in Brazil. There is the possibility to occur reproductively isolated populations, leading to evolutionary processes of speciation. Furthermore, clustered clades with divergent species can bring evidences of species wrong morphologically identified, presents in databases. The survey of the occurrence of Wolbachia was based on the wsp gene of the endosymbiont and the phylogenetic analyses were performed to infer the evolutionary history of these bacteria in the populations of fire ants. There was a great diversity of Wolbachia in the genus Solenopsis, with 51% of the analyzed colonies presenting infection and the highest incidence was found in populations from southern Brazil. Low variability was found among the different strains of Wolbachia within the A and B supergroups. The results also suggest that horizontal transmission may be occurring from the social parasite S. daguerrei.