Metabolomics provides an unprecedented window on diverse plant secondary
metabolites that represent a potentially critical niche dimension in
tropical forests underlying co-existence. Here, we used untargeted
metabolomics to evaluate the chemical composition of 358 tree species
and its relationship to phylogeny and variation in light environment,
soil nutrients, and insect-herbivore leaf damage in a tropical rain
forest plot. We found that tree species that co-occur locally are less
chemically similar than random, and that local chemical dispersion and
metabolite diversity reduce herbivory, especially that of specialist
insect herbivores. Our results suggest that plant secondary metabolites
have the potential to mediate plant-herbivore interactions in a manner
consistent with diversity maintenance at the community scale.