Schematic diagram of microecological relationships in termite nests. a) Fungus-growing termites carry calcium oxalate into their nests and accumulate oxalotrophic bacteria (OxB); b)The degradation of oxalate by OxB can reduce the toxicity of oxalate, regulate the pH of the fungus comb, form carbonates and thus maintain conditions (pH, temperature, humidity, CO₂ concentration etc.) conducive to the growth of Termitomyces fungi; c) The termite nest provides a rich nutrient substrate for the growth of Termitomyces fungi, while the fungi provide mycelium rich in nutrition (especially nitrogen source) for termites; d) CO₂ by the metabolism of termites, Termitomyces fungi and OxB in the active termite nests are the inhibitory factors for the growth of xylariaceous fungi in the active termite nest to some extent.