flies, vectors of fungal spores, are infected by .

fungi are endophytes within grasses that can form stromata on culms of their hosts. flies visit the stromata for egg laying and in the process can vector spermatial spores, thereby cross fertilising the fungus. Following egg hatch, larval flies consume fungal tissue and spores. Thus, individuals with traits that limit larval consumption could be at a selective advantage. We assessed fly larvae from sites within the United States and Europe for infection by the bacterial sexual parasite through amplification of the surface protein gene (). Nearly 70% of fly larvae in our samples were infected by . This is the first record of infection by within and could have far reaching effects on not only the fly host, but also the fungi upon which feeds as well as the grass host within which the fungi live. For example, infection by could limit consumption of spores by larvae if the bacteria promoted premature larval death.