Quantitative aspects of proline utilization during flight in tsetse flies

ABSTRACT. The proline concentration of the haemolymph in resting tsetse flies provides a reasonable indication of their total proline content. Estimates of pre-flight proline content obtained on this basis were compared with the proline content of flies that had been flown for different durations to provide an estimate of the rate of proline consumption at different stages of flight. The results indicate that the apparent ability of tsetse flies to continue flight after their proline reserves have been exhausted is an artefact of experimental procedure. It is concluded that the flight capacity of tsetse flies is effectively limited by the magnitude of their proline reserve, although this reserve is capable of being supplemented to some extent by the limited synthetic capacity of the fat body.