Statistical Analysis
Data was assessed for normality, and non-normal data was transformed using natural logarithms or square root transformations when necessary. If data transformations were unsuccessful, non-parametric tests were used to determine significance. A one-way ANOVA followed by Tukey’spost hoc test was used for caterpillar RGR and plant nutrient content analysis. Caterpillar percentage leaf consumption area was compared using paired T-tests between the treatments for the two-choice assays. For the three-caterpillar choice assay, the percentage leaf area consumed was compared using the non-parametric Friedman’s test, followed by Dunn’s post-hoc test. Caterpillar first finishes and establishes were compared using Chi-square tests with 1:1 choice assumption. Differences in the average eggs laid on no-salt-treated and salt-treated plants were compared using a two-way ANOVA (repeated measures model). Plant defense protein levels (PPO and TPI) were analyzed using a mixed-effects model. Volatile emission differences under salt treatment were analysed using a permutational multivariate analysis of variance (PERMANOVA, with salt x herbivory as factors). Student’s T-test was conducted between no-salt and salt treatments under herbivory and no herbivory for individual volatile compounds.