Data from: Molecular characterisation of faecal bacterial assemblages among four species of syntopic odonates

Factors such as host species, phylogeny, diet, timing, and location of
sampling are thought to influence the composition
of gut-associated bacteria in insects. In this study, we compared
the faecal-associated bacterial taxa for three Coenagrion and one
Enallagma damselfly species. We expected high overlap in representation of
bacterial taxa due to the shared ecology and diet of these species. Using
metabarcoding based on the 16S rRNA gene, we identified 1513 sequence
variants, representing distinct bacterial ‘taxa’. Intriguingly, the
damselfly species showed somewhat different magnitudes of richness of
ZOTUs, ranging from 480 to 914 ZOTUs. In total, 921 (or 60.8% of the 1513)
distinct ZOTUs were non-shared, each found only in one species, and then
most often in only a single individual. There was a surfeit of these
non-shared incidental ZOTUs in the Enallagma species accounting for it
showing the highest bacterial richness and accounting for a sample-wide
pattern of more single-species ZOTUs than expected, based on comparisons
to the null model. Future studies should address the extent to which
faecal bacteria represent non-incidental gut bacteria and whether abundant
and shared taxa are true gut symbionts.

宿主物种、系统发育关系、食性、采样时间与采样地点等因素，被认为会影响昆虫肠道相关细菌的群落组成。本研究针对3种蟌属（Coenagrion）与1种蓝蟌属（Enallagma）的豆娘，比较了其粪便相关细菌类群。鉴于这些物种共享相似的生态特征与食性，我们预期其细菌类群的组成会存在较高的重叠度。本研究基于16S核糖体RNA基因（16S rRNA gene）的宏条形码（metabarcoding）技术，共鉴定得到1513个序列变异体，对应不同的细菌‘类群’。有趣的是，不同豆娘物种的ZOTUs（零半径操作分类单元，Zero-radius Operational Taxonomic Units）丰富度存在一定差异，范围在480至914个之间。总计有921个独特ZOTUs（占总序列变异体数的60.8%）为物种特有，即仅在单个物种中检出，且其中多数仅存在于单一个体体内。蓝蟌属物种中这类特有偶然ZOTUs的数量远超预期，这也是其细菌丰富度最高的原因；结合零模型（null model）对比分析的结果，该类群呈现出比预期更多的单物种特有ZOTUs，这一模式在整个样本集内均存在。未来的研究应进一步明确：粪便细菌在多大程度上能够代表非偶然性的肠道细菌，以及丰度较高且共享的细菌类群是否为真正的肠道共生体。