Determining the factors that direct the co-evolution of plants and the insects that feed on the plants have been a central question in the field of plant-insect interactions. This project will provide a quantitative assessment of the role of plant structure and chemical defenses, and biogeographical distributions in directing the evolution of host shifts in plants. More specifically, the PIs will develop DNA sequences to reconstruct the evolutionary trees of the ancient and speciose Blepharida - Bursera system. Bursera (New World tropical shrubs and trees related to frankincense and myrrh) are one of the most diverse and abundant groups of plants in tropical dry forests, which are a predominant vegetation type in Mexico, while Blepharida includes about 45 species in the New World. The Blepharida - Bursera system is considered on the best example of an old interaction between a herbivore and a plant. Thus, it is an ideal system for testing macroevolutionary questions. The information generated from this project will provide a precise evaluation of the importance of plant defensive chemicals and defensive morphology in the marcoevolution of host exploitation and will help in understanding the evolution of insect-plant interactions. In addition, it will clarify the Systematics and evolution of an important group of Mexican plants and insects, while addressing issues that are very important to the areas of plant-insect interactions, macroevolution and general evolution.
