We propose an international network to explore this key knowledge gap in understanding the effects of pests and pathogens in accelerating tropical rainforest tree mortality during drought. The project will deliver an integrated and focused anlaysis, using expertise in plant physiology, forest ecology and microbial and insect ecology. It will also make use of the unique leverage of the world's only long-term drought experiment network in tropical forests. We will use field-based workshops at two current tropical forest drought experiments, in Australia and Brazil, to bring together experts in plant function, the effects of pest and pathogen ('biotic') attack on woody tissue, and vegetation modelling. New ground-based and remotely-sensed measurements will be examined to test for relationships between measures of biotic attack and metrics of plant function during experimental drought. We will compare responses in different tree size classes, tree species groups, and at the level of the forest ecosystem (large experimental plot treatment). The outcome will be new insights into the causes of tropical rainforest tree death from drought, in relation to plant physiology and insect or microbial attack. This insight will be delivered in the form of new data, new scientfic articles and information that can be used by vegetation modellers to predict the effects of drought on tropical forests in the future. The group of experts built using these funds will form a pre-eminent multi-disciplinary consortium in the subject area, capable of advancing the subject into the future for the benefit of the science, interested environmental policy makers and university educators.