ИСТИНА

Mycorrhizal (EMF) and saprotrophic (SF) fungi play important, but yet insufficiently defined, role in terrestrial food webs. The feeding links between invertebrates and EMF/SF received recent attention due to development of instrumental methods. Here we report preliminary results of a study on the interactions between plants, fungi and invertebrates in a field experiment on high-moors in Central Forest Nature Reserve (56.47N, 33.05E), Russia. We aimed to test the usability of stable isotope analysis (i.e. the δ13С and δ15N values) to identify feeding by invertebrates on different functional types (EMF vs. SF) and parts (mycelium vs. fruit bodies) of macromycetes on a high-moor. Fruit bodies of SF (δ13C = -23.6±0.3‰ [SD]) were significantly enriched in 13C compared to mycorrhizal tips (δ13C = -26.4±0.6‰), but not to EMF fruit bodies (δ13C = -24.2±0.4‰). The δ15N of mycorrhizal tips (δ15N = -3.6±1.7‰) was significantly lower, than in EMF (δ15N = 2.5±0.9‰) and SF (δ15N = -0.6±1.1‰) fruit bodies but significantly higher than in Pinus sylvestris tissues. Mycophagous invertebrates feeding on mycelium and fruit bodies differed in δ13C values, but not δ15N values. Overall, these data indicate that main trends in EMF/SF isotopic division within fungal organisms become less pronounced between in a highmoor. And the isotopic fractionation between EMF mycelium and fruit bodies has nearly similar values compared with data from forest ecosystems. The isotopic analysis can be applied to identify feeding links between invertebrates and EMF/SF on high-moor. This study was supported by the Russian Foundation for Basic Research (Project No 17-04-01856).