Gut bacteria from giant stick insect guts

Two stick insects were dissected and bacteria from their guts werecultivated and identified. Additionally, bacterial genomic DNA (gDNA) wasisolated from the samples using a kit optimised for use with soil bacteriaand the samples were submitted for 16S sequencing. The two samples,originating from two separate stick insects, contained 9450 and 8450 validreads, yielding 97 and 53 operational taxonomic units (OTUs)respectively. The rarefaction curve reached a plateau indicating that thebacterial diversity in the guts has been sufficiently sampled. Out of thesample with 97 different OTUs, only 12 were present at above 1% abundance;the most abundant strain was Serratia marcescens, which constituted 33%bacterial reads retrieved from the D. gigantea guts. The other gut samplecontained 53 OTUs; five of these were present above 1% abundance. Again,Se. marcescens was the dominating strain in the gut community with 91%abundance. Se. marcescens is a common pathogen of insects but it can bealso found in healthy insects. The only bacterial order found in the gutswas Enterobacteriales. Other strains shared by the two gut communitiesare: Pantoea beijingensis, Lellottia amnigena, and Enterobacter asburiae.