Enchytraeids, also known as pot worms, represent one of the least studied groups of soil mesofauna. These organisms can be found throughout the globe from coasts to deserts reaching high densities and biomass, but their specific roles within the soil food web remain a stark knowledge gap. Enchytraeid species are involved in belowground trophic interactions, which could be distinguished by their morphological characteristics and ecological traits. To quantify this, we analyzed stable isotopes δC and δN in 16 enchytraeid species across various biomes and habitats in European Russia. Their isotopic niches were compared with different potential food sources and other soil invertebrates. We found that the total δC and δN range by across single enchytraeid samples reached 8 and 11‰, and isotopic niche of species depends on soil stratification and is reflected in the chaeta number per bundle, and, to a lesser extent, on the size or genera identity. These findings enabled us to split enchytraeids into three guilds within the functional group of secondary decomposers: (i) epigeic – that include litter-dwelling species that predominantly feed on plant material but also can ingest microorganisms; (ii) epi-endogeic – inhabiting upper humified soil and F-litter horizons, and feed primarily on various saprotrophic microorganisms; (iii) endogeic – consuming old processed humified and dissolved organic matter in lower H-horizon and even mineral A-horizons beneath. Our results are an important step forward in integrating enchytraeids into the next-generation food web models, not as a single black box, but as multiple blocks delivering different functions.

中文翻译：

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enchytraeids 是否有不同的营养位？稳定同位素（δ13C、δ15N）证据

Enchytraeids，也称为盆栽蠕虫，是研究最少的土壤中动物群之一。这些生物体遍布全球，从海岸到沙漠，其密度和生物量很高，但它们在土壤食物网中的具体作用仍然存在明显的知识差距。 Enchytraeid 物种参与地下营养相互作用，可以通过其形态特征和生态特征来区分。为了量化这一点，我们分析了俄罗斯欧洲部分不同生物群落和栖息地的 16 种昆虫物种的稳定同位素 δ13C 和 δ1N。将它们的同位素生态位与不同的潜在食物来源和其他土壤无脊椎动物进行了比较。我们发现单个 enchytraeid 样品的总 δ13C 和 δN 范围达到 8 和 11‰，物种的同位素生态位取决于土壤分层，并反映在每束毛毛数量上，并且在较小程度上反映在尺寸或大小上。属身份。这些发现使我们能够将次级分解者的功能组中的 enchytraeids 分为三个类别：（i）表层 - 包括主要以植物材料为食但也可以摄入微生物的垃圾栖息物种； (ii)表内生——栖息于上层腐殖质土壤和F-凋落物地层，主要以各种腐生微生物为食； (iii) 内生的——消耗较低 H 层甚至下方矿物 A 层中旧的加工过的腐殖化和溶解的有机物。我们的结果是将 enchytraeids 集成到下一代食物网模型中的重要一步，不是作为单个黑匣子，而是作为提供不同功能的多个块。