Mechanisms by which mycorrhizae and competition altered herbivory
Overall, mycorrhizae decreased plant nutritional quality by 19% (Fig 2, F1,78=6.40 p < 0.001). Plants inoculated with mycorrhizae and experiencing competition had 13% lower nutritional quality (elevated C/N ratios) in response to jasmonic acid induction (three- way interaction between competition, mycorrhizae and jasmonic acid induction (Fig. 2, F1,78=5.35, p=0.024). In contrast, plants grown without mycorrhizae did not respond to JA induction by altering nutritional quality. The % carbon in the leaf tissue remained constant across all treatments (Mycorrhizae F1,45=0.229 p=0.634, Competition F1,45=1.063 p=0.307, Induction F1,45= 0.017 p=0.898) so the changes in the C/N Ratio was driven by changes to the percent Nitrogen (df=53, R2=0.930, p>0.001).