Figure 2. Correlations between constitutive or induced defenses and herbivore pressure across 12 non-native plant species and 12 native plant species. Relationships between the percentage of damaged leaf area in the common garden experiment and constitutive defense assessed by generalist Spodoptera littoralis larval weight gain on the leaves of healthy plants (A) and assessed by phenolics (C) and triterpenoids (E) contents in the leaves of healthy plants. Relationships between the percentage of damaged leaf area in the common garden experiment and induced defense assessed by difference in S. littoralis larval weight gain on the leaves between healthy and damaged plants [-1 × (larval weight gain on the leaves of damaged plant – average of larval weight gain on the leaves of healthy plant), B], and assessed by differences in phenolics in the leaves between healthy and damaged plants (content in the leaves of damaged plant – average of content in the leaves of healthy plant, D) and difference in triterpenoids on the leaves between healthy and damaged plants (content in the leaves of damaged plant - average of content in the leaves of healthy plant, F). Each point represents individual non-native species (red points) and native congeners (blue points). Lines indicate significant linear relationships. The embedding boxplots represents the comparison for each group of species overall. * indicate p <0.05 and *** indicate p <0.001.