Interactions of earthworm species with their environment and in particular the soil they inhabit is poorly understood. In this study, we aimed to use mid infrared absorption (MIR) spectroscopy of earthworm bodies in combination with discriminant analysis of principal components (DAPC), in order to investigate if their biogeochemical composition is determined by their species belonging or the soil they inhabit. Our conceptual approach included the comparison of MIR spectra of four earthworm species (Lumbricus terrestris, Allolobophora chlorotica, Aporrectodea caliginosa and Aporrectodea icterica) sampled from four different agricultural fields in France. Moreover, we tested the influence of the habitat on the earthworm MIR spectra by exchanging individuals and soils in an incubation experiment.

MIR spectra varied according to species and sampling site. The MIR spectra of earthworm bodies also changed during the incubation experiment, and for L. terrestris, A. chlorotica and A. icterica depended on the properties of the soil ingested. This suggested that the food source in different habitats impacted the biogeochemical composition of earthworm bodies. DAPC allowed for the identification of earthworm species ranging from 64 to 100% of accuracy (mean 78%). We thus conclude that MIR spectroscopy may be a suitable approach to identify earthworm species, but that their signature may also allow to investigate their ecology as determined by the soil they inhabit.

poor物种与其环境，尤其是它们所居住的土壤之间的相互作用了解得很少。在这项研究中，我们旨在将worm体的中红外吸收（MIR）光谱与主要成分判别分析（DAPC）结合使用，以研究其生物地球化学组成是否由其物种或居住的土壤决定。我们的概念方法包括四个蚯蚓物种（MIR光谱的比较蚯蚓，Allolobophora chlorotica，Aporrectodea caliginosa和Aporrectodea icterica）从法国的四个不同农业领域取样。此外，我们通过在孵化实验中交换个人和土壤来测试栖息地对worm MIR光谱的影响。

MIR光谱根据物种和采样地点而变化。蚯蚓体的MIR光谱培养实验过程中也发生了变化，并为L.蒺藜，A. chlorotica和A. icterica取决于摄入的土壤特性。这表明不同生境的食物来源影响了bodies体的生物地球化学组成。DAPC可以识别worm种类，准确度范围为64％至100％（平均78％）。因此，我们得出的结论是，MIR光谱法可能是识别worm物种的合适方法，但是它们的特征也可能允许调查它们所居住的土壤所决定的生态。