THE REGULATION OF GROWTH BY LOCUSTS THROUGH POSTINGESTIVE COMPENSATION FOR VARIATION IN THE LEVELS OF DIETARY-PROTEIN AND CARBOHYDRATE

Post-ingestive responses to four different diets containing protein an d digestible carbohydrate in balanced (7% protein, 7% digestible carbo hydrate or 21% protein, 21% digestible carbohydrate) or unbalanced pro portions (7% protein, 21% digestible carbohydrate or 21% protein, 7% d igestible carbohydrate) were assessed in fifth stadium Locusta migrato ria. Amounts eaten, defaecated and grown were measured across the fift h stadium. Results showed that locusts differentially utilized ingeste d protein and carbohydrate and consequently achieved similar growth on all four diets despite having ingested very different amounts of prot ein and carbohydrate. Nutrients in excess of requirements were voided from the animal mainly after digestion and absorption from the gut. In the case of excess nitrogen, a major route for removal was through in creased uric acid excretion, while for carbohydrate the major removal mechanism was apparently via respiration.