Phytochemical diversity impacts herbivory in a tropical rainforest tree community

Metabolomics provides an unprecedented window into diverse plant secondary metabolites that represent a potentially critical niche dimension in tropical forests underlying species co-existence. Here, we used untargeted metabolomics to evaluate chemical composition of 358 tree species and its relationship with phylogeny and variation in light environment, soil nutrients, and insect-herbivore leaf damage in a tropical rain forest plot. We report no phylogenetic signal in most compound classes, indicating rapid diversification in tree metabolomes. We found that locally co-occurring species were more chemically dissimilar than random, and that local chemical dispersion and metabolite diversity was associated with lower herbivory, especially that of specialist insect herbivores. Our results highlight the role of secondary metabolites in mediating plant-herbivore interactions and their potential to facilitate niche differentiation in a manner that contributes to species coexistence. Furthermo..., Plant secondary metabolites were extracted and analyzed from leaves using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), following Sedio et al. (2021) with slight modifications. Three branches were taken from different directions, and 10 leaves per branch were sequentially selected from top to bottom on each branch to avoid overestimating the percent herbivory and ignoring certain types of herbivores (Woodman & Fernandes, 1991). All collected leaves were scanned, and the leaf area was calculated using ImageJ software (Abramoff et al., 2004). The percent herbivory for each leaf was calculated as the ratio of damaged area to estimated undamaged area, with higher percentages indicating greater herbivore damage (Kurokawa & Nakashizuka, 2008). We classified herbivore damage into broad categories (e.g., hole feeding, margin feeding) according to Labandeira et al. (2007) and further divided them into three diet-breadth categories: generalized, inte..., , # Phytochemical diversity impacts herbivory in a tropical rainforest tree community

[https://doi.org/10.5061/dryad.n2z34tn32](https://doi.org/10.5061/dryad.n2z34tn32)

## Description of the data and file structure

1\. In the El\_submitted file\, qua was plot name; species richness is the species richness in each plot; scale\_herbivory\.ratio is herbivory ratio data which was scaled; scale\(generalized\.ratio\) was scaled generalized ratio; scale\(specialized\.ratio\) was scaled specialized ratio; soil\.pc1\, soil\.pc2 and soil\.pc3 were the first three axes after the principal component analysis of soil nutrient indicators; scale\_PSMshannon was Shannon index of plant secondary metabolites which was scaled; all\.classified\.nri was the net\-relatedness index of all classified compounds; all\.chemical\.diversity was diversity of all chemical compounds; Alkaloids\.diversity\, Amino\.diversity\, Carbohydrates\.diversity\, Fattyacids\.diversity\, Polyketides\.diversity\, Shikimates\.diver...