Abstract/Summary

To characterize the gut and faeces bacterial communities (BCs) of Porcellionides pruinosus using high-throughput sequencing. A similar experimental design to those of laboratorial tests for exposure scenarios (e.g. ecotoxicological tests) was used to serve as basis for BCs analysis in a multi-level approach. Faeces and purged guts of isopods (n= 3 x 30) were analysed by pyrosequencing the V3-V4 region of 16S rRNA encoding gene. Results showed that gut and faecal BCs were dominated by Proteobacteria, particularly by an OTU (Operational Taxonomic Unit) affiliated to genus Coxiella . Diversity and richness values were statistically higher for faecal BC, mainly due to the occurrence of several low-abundance phylotypes. These results may reflect faecal carriage of bacterial groups that cannot settle in the gut. BCs of P. pruinosus comprised: (1) common members of the soil microbiota, (2) bacterial symbionts, (3) bacteria related to host metabolic/ecological features, and (4) bacterial etiological agents. Comparison of BC of this isopod species with the BC from other invertebrates revealed common bacterial groups across taxa. The information provided by this work is useful in future ecotoxicological or biomonitoring assays for several exposure scenarios where the analysis of P. pruinosus BC will be of value as an additional indicator.