Forest Structure and Fungal Endophytes

Interactions among endophytic fungi, woody plants and herbivores are usually studied emphasizing fungal mediated plant-herbivore interactions. Seeking evidence for indication of causal relationships between fungi and herbivores sharing the host plant has been self-feeding reasoning in endophyte literature since the findings that some endophytes, particularly seed-borne grass-endophytes in agronomic arena, negatively affect herbivores. Although many studies with natural grass systems, and especially with horizontally by spores transmitted tree-endophytes, have shown more variable effects, alternative approaches have seldom been brought up for discussion. Here, I suggest that the mutualistic nature of plant fungus interactions via enhanced herbivore resistance should be reconsidered especially when focusing on woody plants, and focus on the question, how genetic, spatial and age structure of forest affect the species distribution and frequency of endophytes.