Three-way interaction: severity of tufted grass fungal infection affects Botanophila fly reproduction

Abstract The interaction between Botanophila flies and Epichloë fungi is one of the few interactions in which grass-associated are ‘pollinated’ by flies. We analysed gains losses for both partners time factors determining cost dynamics. A hypothesis regarding relationship changes severity grass infection with fungus, size fungal sexual structures (stromata), fly presence (expressed as egg larvae numbers) was tested. During a 3-year study conducted on permanent field plots, wild tussocks Holcus lanatus visits to stromata were monitored. An increase number shoots reduction observed. From year another, deposited fewer eggs stromata, larval body mass decreased. explain these results deterioration condition due increased infection, resulted higher maintenance costs parasite.