Prevalence and Genetic Diversity of a Microsporidian Parasite in the Black Imported Fire Ant and Its Social Parasitic Ant (Formicidae: Myrmicinae: ) in Buenos Aires Province, Argentina.

Microsporidia are natural pathogens of arthropods and have been used as biological control against insect pests. In the United States, efforts to control the invasive Red Imported Fire Ant, , and Black Imported Fire Ant, , have included the use of the microsporidium, . However, there is limited information about the genetic differences among the microsporidian variants found in and in . In this study, we assessed the prevalence and genetic diversity of in native populations of in Argentina (South America). Additionally, we examined the social parasitic ant, , which is found in some nests, for the presence of this microsporidium. The survey of 219 nests revealed infections in all five sites analyzed, with 28 colonies (12.8%) positive for the microsporidium. Among the 180 individuals collected, seven ants (3.9%) from three sites tested positive for . Phylogenetic analyses of the microsporidian variants present in and based on partial small subunit ribosomal gene sequences (SSU rRNA) showed that both ant species shared the same variant, which is different from the ones found in . Further studies are needed to determine the pathogenicity of genetically different variants among species.