High Incidence of Wolbachia Infection on Solenopsis (Hymeoptera: Formicidae) Populations From Urbanized Areas

Abstract:
Solenopsis ant genus has a worldwide distribution but species from S. saevissima species group native to South America, and popularly known as fire ants, have been introduced accidentally in several countries worldwide. Despite a high diversity species in the Neotropical region, their ecology and life history in Brazil are poorly known. These ants are highly aggressive and are responsible for accidents that can lead to anaphylactic shock and death. These ants are widely distributed in Brazil, including on urban areas. Wolbachia (Alphaproteobacteria, Rickettsiales) are intracellular bacteria inherited from the egg cytoplasm, found in large numbers of reproductive tissues in many arthropods. These bacteria can cause reproductive alterations in their hosts including cytoplasmic incompatibility, parthenogenesis and feminization of genetic males, and increase transmission to subsequent generations. There is widespread interest to use these endobacteria in biological control. Its incidence among ants of the genus Solenopsis is high but little is known about its occurrence on Solenopsis species associated to urban areas. In the present study we inferred the presence and distribution of these endosymbiont on populations of Solenopsis of such areas from Southern and Southeastern of Brazil, by means of PCR amplification of the wsp gene, and sequences of this fragment to infer a phylogenetic relationship of this endosymbiont associated with the urban pest. We found high frequency of Wolbachia among Solenopsis species analyzed. However, little genetic variability was found among the different Wolbachia strains suggesting possible events of horizontal transmissions of Wolbachia. Consequently, knowing the strain diversity of Wolbachia in natural populations of Solenopsis can be efficient on a future program of biological control of those pest ants.