Phylogenetic relatedness, functional traits, and spatial scale determine herbivore co-occurrence in a subtropical forest

The mechanisms driving species co-occurrence are varied and include biotic interactions, abiotic factors, and scale-dependent processes. Based on a comprehensive dataset of lepidopteran herbivores recorded from a large-scale forest biodiversity experiment, we tested the contribution to herbivore species co-occurrence of herbivore phylogenetic relatedness, plant diversity and functional traits, and spatial scale. We found that Lepidoptera co-occurrence was negatively associated with their phylogenetic relatedness, tree diversity, and defensive traits, but positively associated with nutritional functional traits. Furthermore, species co-occurrence was higher at larger spatial scales (tree species or plot) than at smaller scale (individual trees). Our results provide evidence supporting both environmental filtering and competition exclusion hypotheses, and highlight the significance of functionality in shaping species coexistence of herbivores in plant-arthropod systems.