show Abstracthide AbstractHere we report the characterisation of fungus comb mycobiotas from two fungus-growing termite genera using culture-dependent and -independent approaches to demonstrate that individual termite colonies maintain a single Termitomyces strain, with other fungi being extraordinarily rare. This prompted us to explore the chemical environment and antifungal properties of fungus combs and Termitomyces itself through metabolomics and in vitro assays. This revealed that the fungus comb metabolome consists of a complex array of components of likely fungal, bacterial and plant origins, and displays inhibitory activity towards putative fungal para-sites of the symbiosis.