A mutualistic interaction between a fungivorous nematode and a fungus within the endophytic community of Bromus tectorum

► A fungivorous nematode associated with endophytic Fusarium cf. torulosum in the field. ► Experimentally, the nematode, Paraphelenchus acontioides, preferred F. cf. torulosum to other endophytes. ► The nematode increased relative abundance of F. cf. torulosum in planta. ► Fungivorous nematodes can affect endophyte community structure.