Advances in Insect Physiology, Volume 59, examines the molecular and developmental origins of insect extended phenotypes, their diverse physiological functions, their consequences for the ecology and evolution of insects, and their biotic partners. Chapters cover recent ideas about the significance and roles of extended phenotypes and provide overviews of the latest advances. Written for a broad audience of researchers and students, the book's chapters establish extended phenotypes as focal structures for understanding genotype-to-phenotype maps, the origins and consequences of complex traits among multiple interacting partners, and the roles they may play in providing resilience against climate change.