In this second volume, a few repeat authors describe brand new aspects of their research, while a new group covers recently developing aspects of symbiotic relationships. The book includes updated information on biology and how it influences insect life, supplies two new examples of using symbionts in crop protection, and discusses the recent “bug in a bug” mealy bug case. The book provides analysis and synthesis of cutting-edge research in insect symbiosis that sheds light on the evolution of the host/symbiont relationship, and in turn, on the general study of evolution, physiology, and genetics.