Physiological Systems in Insects, Fourth Edition explores why insects have become the dominant animals on the planet. Sections describe the historical investigations that have led us to our current understanding of insect systems. Integrated within a basic physiological framework are modern molecular approaches that provide a glimpse of the genetic and evolutionary frameworks that testify to the unity of life on earth. This updated edition describes advances that have occurred in our understanding of hormone action, metamorphosis, and reproduction, along with new sections on the role of microbiomes, insecticide action and its metabolism, and a chapter on genetics, genomics and epigenetic systems. The book represents a collaborative effort by two internationally known insect physiologists who have instructed graduate courses in insect physiology. As such, it is the ideal resource for entomologists and those in other fields who may require knowledge of insect systems.