A diverse array of organisms induce plants to form galls. This phenomenon is one of the most striking instances of convergent evolution, yet the underlying mechanism is only well understood in gall-inducing microbes. To determine if gall induction by insects is associated with bacterial symbiosis, we used 16S rRNA gene sequencing to examine the microbiome of a variety of gall-inducing and non-gall-inducing insects. Overall, we did not find any bacterial signature of gall induction among the insect species we surveyed. There were no specific bacterial taxa that were consistently associated with gall induction. Microbiome diversity differed significantly among species of host insects, but not between gall- and non-gall-inducing insect species. Bacterial community composition also differed strongly among insect species, but not in a systematic way between gall-inducing and non-gall-inducing species. Furthermore, two gall-inducing species harbored highly variable microbiomes with relatively few bacterial sequences, characteristics that suggest a lack of abundant bacterial symbionts. Together, these findings argue that gall induction is not consistently mediated by a bacterial symbiont or bacterial community and may be symbiont-independent, at least in some insect species. While symbionts may still contribute to gall induction in specific instances, we suggest that the convergent evolution of gall induction is more typically driven by endogenous mechanisms, with potential contributions from horizontal gene transfer.

各种各样的生物体诱导植物形成胆汁。这种现象是趋同进化最明显的例子之一，但其潜在机制只有在诱发胆汁的微生物中才得到很好的理解。为了确定昆虫引起的胆汁分泌是否与细菌共生相关，我们使用了16S rRNA基因测序来检查多种引起胆汁和不引起胆汁的昆虫的微生物组。总体而言，我们在所调查的昆虫物种中未发现胆汁诱导的任何细菌特征。没有特异性与胆汁诱导相关的细菌类群。宿主昆虫物种之间的微生物组多样性差异显着，但诱发胆汁和不引起卵囊的昆虫物种之间无显着差异。昆虫物种之间的细菌群落组成也存在很大差异，但不能以系统的方式在诱发胆和非诱发胆的物种之间进行。此外，两个引起胆汁的物种具有高度可变的微生物组，具有相对较少的细菌序列，这表明缺乏丰富的细菌共生体。在一起，这些发现表明胆汁诱导不是由细菌共生体或细菌群落一致地介导的，并且至少在某些昆虫物种中可能与共生体无关。虽然共生体在特定情况下仍可能有助于胆汁诱导，但我们建议胆汁诱导的趋同进化更典型地是由内源性机制驱动，而水平基因转移可能具有贡献。两个诱发胆汁的物种具有高度可变的微生物群，具有相对较少的细菌序列，这些特征表明缺乏丰富的细菌共生体。在一起，这些发现表明胆汁诱导不是由细菌共生体或细菌群落一致地介导的，并且至少在某些昆虫物种中可能与共生体无关。虽然共生体在特定情况下仍可能有助于胆汁诱导，但我们建议胆汁诱导的趋同进化更典型地是由内源性机制驱动，而水平基因转移可能具有贡献。两个诱发胆汁的物种具有高度可变的微生物群，具有相对较少的细菌序列，这些特征表明缺乏丰富的细菌共生体。在一起，这些发现表明胆汁诱导不是由细菌共生体或细菌群落持续介导的，至少在某些昆虫物种中可能与共生体无关。尽管共生体在特定情况下仍可能有助于胆汁诱导，但我们建议胆汁诱导的趋同进化更典型地是由内源性机制驱动的，而水平基因转移可能具有这种作用。至少在某些昆虫物种中。尽管共生体在特定情况下仍可能有助于胆汁诱导，但我们建议胆汁诱导的趋同进化更典型地是由内源性机制驱动的，而水平基因转移可能具有这种作用。至少在某些昆虫物种中。尽管共生体在特定情况下仍可能有助于胆汁诱导，但我们建议胆汁诱导的趋同进化更典型地是由内源性机制驱动的，而水平基因转移可能具有这种作用。