The nature of plant-endophyte relationships may be affected by the addition of interacting species. Firstly, we show how the root hemiparasitic plant (Rhinanthus serotinus) can steal defending mycotoxins produced by the symbiotic endophytic fungus (Neotyphodium uncinatum) living within their shared host grass (Lolium pratense). The uptake of defensive mycotoxins from the endophyte infected host increases resistance of the hemiparasitic plant to the aphid (Aulacorthum solani). Endophyte infection increased performance of the hemiparasite but reduced the growth of the host grass, changing the mutualistic endophytic fungus to parasitic. Secondly, we present the interactions among endophyte, host plant, aphid herbivore (Rhopalosiphum padi) and aphid transmitted grass virus (BYDV). Endophyte infection lowered the frequency of BYDV in L. pratense. The reproduction of R. padi aphids was decreased on endophyte-infected plants compared to uninfected. With these results we would like to emphasise the importance of experiments with several community members to shed light on the complexity of endophyte-mediated community interactions. Keywords: Lolium pratense, Neotyphodium uncinatum, Rhinanthus serotinus, BYDV, aphid, multitrophic interactions