Bacterial communities in the midgut of Ponerine ants (Hymenoptera: Formicidae: Ponerinae)

Symbiotic microorganisms are directly related to the ecological success of host insects, influencing many aspects of their biology. The present study is the first to investigate the microbiota associated with ants of the subfamily Ponerinae and aims to identify the bacterial midgut communities of Dinoponera lucida, Neoponera curvinodis, Pachycondyla striata, Odontomachus brunneus and Odontomachus bauri relied on culture-dependent technique, particularly 16S rRNA sequencing. The greatest species richness was observed in O. bauri, with 15 OTUs, followed by D. lucida with five OTUs, O. brunneus, with four OTUs, and N. curvinodis and P. striata, both with three OTUs. There were representatives of the phyla Actinobacteria, Proteobacteria, Tenericutes and Firmicutes, including the genera Bartonella, Mesoplasma, Mesorhizobium, Spiroplasma, Wolbachia and Serratia in the guts of the studied Ponerine ants. Spiroplasma and Mesoplasma were found to be prevalent in the studied ants and they were the only genera of bacteria found in more than one of the analyzed ant species suggesting they might be beneficial symbionts. The low microbial diversity observed given the predatory trophic habits of the species studied suggests that there is selection for these microorganisms, predominantly preserving symbionts with functional roles that are able to colonize this environment. It is also valid to infer that the identified bacteria are predominant in the gut and exhibit mutualistic functions that are important mainly for immunity, but also to reproduction and nutrition; moreover, a subset may be parasites that could have considerable impacts on the studied ants.