Arbuscular mycorrhizal (AM) fungi inhabit the soil and roots of most plants on land. A simple interpretation of this symbiosis is one where the fungi obtain carbon from their host plants, while the fungi supply plants with access to nutrients such as phosphorus. However, AM fungi play important roles in multiple ecosystem processes, they are important to plant community assembly, soil aggregation, and affect plant interactions with insect herbivores.
Indeed, most terrestrial plants will be attacked by one, if not many, species of herbivorous invertebrates. As such, mycorrhizal-plant-herbivore interactions are ubiquitous. As we progress our understanding of how the AM symbiosis can affect insect herbivores, it is less clear how the diversity of AM fungi affects these interactions.
Through a series of experiments, we explored how AM fungi can affect plant defences against insect herbivory, and how different resident fungal communities can shape how plants respond to insect attack. Our results demonstrate how AM fungal diversity can drive key plant defence mechanisms, and how community composition can affect plant responses to herbivory. We also show how the community structure of root-colonising AM fungi are impacted by belowground insect herbivory. Overall, our findings highlight the importance of fungal diversity to mycorrhizal-mediated plant-herbivore interactions.