Abstract
Determining the macroevolutionary importance of plant chemistry on herbivore host shifts is critical to understanding the evolution of insect-plant interactions. Molecular phylogenies of the ancient and speciose Blepharida (Coleoptera)–Bursera(Burseraceae) system were reconstructed and terpenoid chemical profiles for the plant species obtained. Statistical analyses show that the historical patterns of host shifts strongly correspond to the patterns of host chemical similarity, indicating that plant chemistry has played a significant role in the evolution of host shifts by phytophagous insects.