The utilization of trehalose during flight by the housefly, Musca domestica

Abstract

The male housefly, Musca domestica, utilizes trehalose during flight. However, the rate of utilization of treahlose is most rapid during the first few minutes of continuous flight (i.e. during the first 5 min of flight, the rate of utilization of trehalose is 187 μg/thorax per hr; this results in a thoracic trehalose level of one-third of that of the unflown fly, after 5 min of flight). However, as the period of flight is extended, the apparent rate decreases very rapidly, so that the thoracic trehalose level actually continues to rise with increasing duration of flight period. It is concluded that, following initial rapid utilization of trehalose, a secondary metabolic pool becomes implicated, so as to restore (and maintain) the thoracic trehalose levels at as high as 50 per cent of that of unflown flies, for thoraces of flies which have been permitted to fly for as long as 4·5 hr. Flight-exhausted flies, when fed on a solution of glucose, fructose, maltose, sucrose, and trehalose, resumed flight, without external stimulation, but feeding galactose, mannose, and cellobiose failed to do so. However, injection of solutions of glucose, fructose, sucrose, and trehalose did not initiate flight in such flight-exhausted flies. These data indicate that a complex, metabolic route is normally involved in the energizing of flight.