Gut microbiome of three species of Odonata

The influence of diet and host specificity on the fecal microbiome of three adult dragonfly species, Pseudothemis zonata, Orthetrum lineostigma, and Orthetrum melania, was investigated. The fecal bacterial communities were analyzed using 16S rRNA gene sequencing, and stable isotope analysis was used to investigate their food sources. The results showed significant differences in the composition of fecal bacterial communities among the three species, with host specificity potentially playing a more important role than diet. The dominant phyla in the fecal bacterial communities of all three species were Firmicutes, Proteobacteria, and Bacteroidetes. The operational taxonomic units (OTUs), Shannon index, and phylogenetic diversity index were not significantly different among the three species, indicating that there were no major differences in the diversity of the fecal bacterial communities. The stable isotope analysis showed that the food sources were similar among the three species, being primarily small insects found near the aquatic habitats. However, the fecal bacterial communities of two closely related species, O. lineostigma and O. melania, were different despite their similar food sources. In contrast, the fecal bacterial communities of O. lineostigma and P. zonata were similar, despite the different food sources of these two species. Our findings suggest that host specificity and diet can influence the composition of the intestinal microbiome in these insects, but the degree of influence may depend on the specific host and environmental conditions.