All organisms need to acquire nourishment in sufficient quantity and quality to grow and reproduce. Food sources need to be located and choices need to be made with respect to their favourability. This issue addresses host location (plants by phytophagous insects, prey by predators or parasitoids) and performance (of phytophagous and carnivorous insects), and the involvement of microorganisms and plant defence responses. All are relevant for understanding the complex interactions within insect communities and the application of biological pest control.