Chapter 183 – Nutrition

Publisher Summary This chapter explores the nutritional habits in insects. The nutritional requirements of insects were at first inferred from knowledge of the chemical compositions of natural foodstuffs. Insects were categorized as carnivorous, omnivorous, or phytophagous, with the appropriate inferences regarding the nutritional content of the animals, plants, and other foods eaten. Studies of food utilization, and the analysis and comparison of foodstuff eaten and excreted or unabsorbed, allowed further assessment of the relative importance of various nutrients for insects with different feeding habits. A thorough knowledge of insect nutrition is essential for understanding the biology of insects. The study of insect nutrition has recently undergone a metamorphosis, in that information gleaned from earlier investigations that focused principally on basic nutritional requirements and rearing technology is now being applied for understanding the feeding strategies, nutritional ecology, and evolution of insects. Nutritional physiology and biochemistry are also advancing, with the molecular arsenal available for Drosophila offering many new opportunities. The neurological bases for food selection and the role of biogenic amines in regulating food choice are beginning to be understood. The chemical composition of the hemolymph is now recognized as a dynamic indicator of nutritional status, affecting food selection and nutrient intake. The metabolic responses of insects to altered nutritional status and the effects of fat body metabolism on hemolymph composition are also being investigated. Future studies employing multidisciplinary approaches will continue to unravel the mysteries of insect nutrition and its consequences and significance to insect biology.