Modern approaches to study plant–insect interactions in chemical ecology

Phytochemical variation among plant species is one of the most fascinating and perplexing features of the natural world and has implications for both human health and the functioning of ecosystems. A key area of research on phytochemical variation has focused on insects that feed on plants and the enormous diversity of plant-derived compounds that reduce or deter damage by insects. Empirical studies on the ecology and evolution of these chemically mediated plant–insect interactions have been guided by a long history of theoretical development. However, until recently, such theory was substantially limited by inadequate data, a situation that is rapidly changing as ecologists partner with chemists utilizing the latest technological advances. In this Review, we aim to facilitate the union of ecological theory with modern chemistry by discussing important theoretical frameworks for studying chemical ecology and outlining the steps by which hypotheses on insect–phytochemical interactions can be advanced using current methodologies and statistical approaches. We highlight unique approaches to isolation, synthesis, spectroscopy, metabolomics and genomics relevant to chemical ecology and describe future areas for research that will bring an unprecedented understanding of phytochemical variation.