Studies on the water relations of adult locusts (orthoptera, acrididae). I. Respiration and the production of metabolic water

Adult males of Locusta migratoria migratorioides (R. & F.) had an oxygen consumption of 120 mm 3 g -1 h -1 at 15°C and 988 mm 3 g -1 h -1 at 37°C, although respiratory quotient in fed insects (0.83) did not alter over this temperature range. Starvation or starvation and desiccation reduced the respiratory quotient from 0.83 to 0.77 indicating a shift in metabolism from carbohydrates towards fats. It is shown that the amount of biologically useful energy produced (in the form of ATP) remains the same, and that a shift from carbohydrate to fat metabolism requires the depletion of a smaller weight of food reserve. The shift is counterproductive in terms of metabolic water production, as only 0.28 mg g -1 h -1 water is produced in starved or desiccated locusts compared with 0.35 mg g -1 h -1 in fed animals.