Format: ORAL

Dale L. Forristera, Mara-Jos Endaraa,b, Abrianna J. Soulea, Gordon C. Younkinc,d, Anthony G. Millsa, John LokvamaKyle G. Dextere, R. Toby Penningtonf, Catherine A. Kidnergh, James A. Nichollsi, Oriane Loiseaue, Thomas A. Kursara, Phyllis D. Coleya

aDepartment of Biology, University of Utah, Aline W. Skaggs Biology Building, 257 S 1400 E, Salt Lake City, UT 84112-0840, USA. bCentro de Investigación de la Biodiversidad y Cambio Climático (BioCamb) e Ingeniería en Biodiversidad y Recursos Genéticos, Facultad de Ciencias de Medio Ambiente, Universidad Tecnológica Indoamérica, Quito, Ecuador. cBoyce Thompson Institute, Ithaca, New York 14853, USA. dPlant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853, USA. eSchool of Geosciences, University of Edinburgh, Old College, South Bridge, Edinburgh EH8 9YL, UK. fDepartment of Geography, University of Exeter, Laver Building, North Park Road, Exeter, EX4 4QE, UK. g School of Biological Sciences, University of Edinburgh, King’s Buildings, Mayfield Road, Edinburgh, UK hRoyal Botanic Gardens Edinburgh, 20a Inverleith Row, Edinburgh, EH3 5LR UK iThe Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australian National Insect Collection (ANIC), Building 101, Clunies Ross Street, Black Mountain ACT 2601, AU.

Because plants and their insect herbivores together account for more than half of the macroscopic diversity on land, their interactions play an extremely important role. From an evolutionary perspective, they are thought to be lockedin a coevolutionary arms race, in which plants evolvenovel defense traitsto which herbivores evolve counter adaptations. We discuss evidence for the role of plant-herbivore interactions in shaping the ecology and evolution of,Inga (Fabacea), a specious tropical treegenus. With a particular focus on the evolution of plant secondary metabolism and ecological significance. To do so we characterized the chemical profile of one-third ofspeciesin the genusInga(c.100, Fabaceae) using ultraperformance liquid chromatography-mass spectrometry-based metabolomics and applied phylogenetic comparative methods to understand the mode of chemical evolution. EachIngaspecies contains structurally unrelated compounds and high levels of phytochemical diversity; closely related species have divergent chemical profiles, with individual compounds, compound classes, and chemical profiles showing little-to-no phylogenetic signal; at the evolutionary time scale, a species' chemical profile shows a signature of divergent adaptation. At the ecological time scale, sympatric species were the most divergent, implying it is also advantageous to maintain a unique chemical profile from community members; finally, we integrate these patterns with a model for how chemical diversity evolves. We find that this chemical divergence plays an important role in shaping the community assembly of tropical trees and shaping the host choice of insect herbivores.