Stephen Simpson has pioneered major developments at the interface of nutritional physiology, ecology, and behaviour. His groundbreaking discovery of the mechanisms that induce swarming in locusts (studies which span neuro-chemistry through to consequences for individual behaviour and population ecology) has immense practical and conceptual benefits. He has also developed a novel class of state-space models for nutrition. His Geometric Framework (GF) powerfully integrates ideas in this field and, although it arose from extensive experiments on insects, is now being applied in a wide variety of contexts, including the search for dietary causes of human obesity.