This project, using comparative transcriptomics, will investigate differential gene expression patterns in genes related to biochemical defenses against biotic stresses, including phytopathogens and insect herbivory, among co-occurring heterospecific dipterocarp saplings of varying phylogenetic distances in Singapore and Pasoh, Malaysia. As my first summer fieldwork, this project will gather data to construct the first chapter of my doctoral dissertation and will also inform future greenhouse and field experiments for subsequent chapters. A stronger understanding of biochemical defense variation will help develop causal explanations of complex plant mortality and survival rates and generate knowledge to enhance the resilience and productivity of economically important plants, including Dipterocarpaceae species used for timber and resin production.