PhD and MSc studies at the University of California, Davis. Previous professorships at Norwegian University of Science & Technology (Trondheim) and University of Alaska Fairbanks.

Evolution and ecology of plant-insect interactions, with emphasis on pollination ecology and insect herbivory. Long-term (macroevolutionary) perspectives on plant-insect (co-)evolution, based on molecular-phylogenetic studies of the evolution of chemical and floral traits and ecological relationships. Quantitative genetics and development of floral traits involved in attracting, rewarding, and manipulating pollinators; correlated evolution, constraint, and evolvability of floral traits. Community ecology, including biotic interactions and effects of local variation in microclimate on the composition and function of plant and insect communities; latitudinal patterns in beta-diversity (species turnover across microhabitats). Biogeography: molecular phylogeography and ecology of Beringian plants and insects. Evolution of plant mating systems and correlated floral traits, with current emphasis on Collinsia and Tonella (Plantaginaceae). Tropical conservation biology, biological consequences of forest fragmentation.