Insects provide excellent model systems for understanding evolutionary ecology. They are abundant, small and relatively easy to rear, and these traits facilitate both field and laboratory experiments. This book has been developed from the Royal Entomological Society's 22nd International Symposium, held in Reading in 2003. Topics include speciation and adaptation; life history, phenotype plasticity and genetics; sexual selection and reproductive biology; insect-plant interactions; insect-natural enemy interactions and social insects.