Termites are intimately tied to the microbial world, as they utilize their gut microbiome for the conversion of plant cellulose into necessary nutrients. Subterranean termites must also protect themselves from the vast diversity of harmful microbes found in soil. However, not all soil microbes are harmful, such as Streptomyces and methanotrophic bacteria that some species of termites harbor in complex nest structures made of fecal material. The eastern subterranean termite, Reticulitermes flavipes, has a simple nest structure consisting of fecal lined galleries. We tested the hypothesis that R. flavipes maintains a select microbial community in its nests to limit the penetration of harmful soilborne pathogens and favor the growth of beneficial microbes. Using Illumina sequencing, we characterized the bacterial and fungal communities in the surrounding soil, in the nest galleries, and on the cuticle of workers. We found that the galleries provide a more beneficial microbial community than the surrounding soil. Bacterial and fungal diversity was highest in the soil, lower in the galleries, and least on the cuticle. Bacterial communities clustered together according to the substrate from which they were sampled, but this clustering was less clear in fungal communities. Most of the identified bacterial and fungal taxa were unique to one substrate, but the soil and gallery communities had very similar phylum-level taxonomic profiles. Notably, the galleries of R. flavipes also harbored both the potentially beneficial Streptomyces and the methanotrophic Methylacidiphilales, indicating that these microbial associations in fecal material pre-date the emergence of complex fecal nest structures. Surprisingly, several pathogenic groups were relatively abundant in the galleries and on the cuticle, suggesting that pathogens may accumulate within termite nests over time while putatively remaining at enzootic level during the lifetime of the colony.

白蚁与微生物世界密切相关，因为它们利用肠道微生物组将植物纤维素转化为必要的营养物质。地下白蚁还必须保护自己免受土壤中各种有害微生物的侵害。然而，并非所有土壤微生物都是有害的，例如链霉菌和甲烷营养细菌，某些种类的白蚁栖息在由粪便材料制成的复杂巢穴结构中。东部地下白蚁Reticulitermes flavipes有一个简单的巢结构，由粪便排列的长廊组成。我们检验了R. flavipes的假设在其巢穴中保持精选的微生物群落，以限制有害的土壤传播病原体的渗透并有利于有益微生物的生长。使用 Illumina 测序，我们表征了周围土壤、巢廊和工人角质层中的细菌和真菌群落。我们发现这些画廊提供了比周围土壤更有益的微生物群落。细菌和真菌多样性在土壤中最高，在廊道中较低，在角质层中最少。细菌群落根据取样的基质聚集在一起，但这种聚集在真菌群落中不太清楚。大多数已鉴定的细菌和真菌分类群对于一种基质是唯一的，但土壤和画廊群落具有非常相似的门级分类学特征。值得注意的是，R. flavipes的画廊还包含潜在有益的Streptomyces和甲烷营养型Methylacidiphilales，表明粪便材料中的这些微生物关联早于复杂的粪便巢结构的出现。令人惊讶的是，在长廊和角质层中，几个致病菌群相对丰富，这表明病原体可能会随着时间的推移在白蚁巢穴内积累，而在白蚁的整个生命周期内可能仍保持在地方性动物水平。