Millipedes are ubiquitous soil invertebrates that play major roles in physical and chemical processes in soil. Despite their importance to soil ecology and their presumed interactions with soil microorganisms, little is known about how millipedes influence and are influenced by soil microbes. Furthermore, it is not fully understood how these millipede-microbe interactions are influenced by available soil nitrogen, which is predicted to increase over the foreseeable future with increased anthropogenic production. Here, using the millipede Cherokia georgiana georgiana as a model and using a manipulative mesocosm and metabarcoding approach, we examine (1) the impacts of millipedes on soil microbial communities (fungi and bacteria) with varying nitrogen addition levels, and (2) the temporal impacts of nitrogen on millipede fecal communities (fungi and bacteria). This research demonstrates that millipede presence strongly alters soil communities and that alterations in nitrogen levels do not impact millipede gut communities. This work also provides the first evidence suggesting that millipede gut communities are predominantly derived from soils rather than leaf litter, though both contribute to gut composition. This work advances our current poor understanding of millipede-soil interactions and provides a framework for further investigations to disentangle the interactive effects of substrate, nitrogen, and time to better understand ecological impacts of these interactions.

千足虫是无处不在的土壤无脊椎动物，在土壤的物理和化学过程中起主要作用。尽管它们对土壤生态学很重要，并且推测它们与土壤微生物的相互作用，但对于千足虫如何影响土壤微生物以及如何受到土壤微生物的影响知之甚少。此外，尚不完全了解这些千足虫-微生物的相互作用如何受到可用土壤氮的影响，土壤氮在可预见的将来会随着人为生产的增加而增加。在这里，使用千足虫Cherokia georgiana georgiana作为模型并使用操纵性的介观和元条形码方法，我们研究了（1）不同添加氮水平的千足虫对土壤微生物群落（真菌和细菌）的影响，以及（2）氮对千足动物粪便群落的时间影响（真菌和细菌）。这项研究表明，千足虫的存在会极大地改变土壤群落，而氮含量的变化不会影响千足虫的肠道群落。这项工作还提供了第一个证据，表明千足虫的肠道群落主要来自土壤而不是枯枝落叶，尽管它们都有助于肠道的组成。这项工作提高了我们目前对千足动物与土壤相互作用的理解，并为进一步研究以弄清基质，氮，