Submaximal power output from the dorsolongitudinal flight muscles of the hawkmothManduca sexta

Abstract

To assess the extent to which the power output of a synchronous insect flight muscle is maximized during flight, we compared the maximum potential power output of the mesothoracic dorsolongitudinal (dl₁) muscles of Manduca sexta to their power output in vivo. Holding temperature and cycle frequency constant at 36°C and 25 Hz, respectively, we varied the phase of activation, mean length and strain amplitude. Under in vivo conditions measured in tethered flight, the dl₁ muscles generated only 40–67% of their maximum potential power output. Compared to the in vivo phase of activation, the phase that maximized power output was advanced by 12% of the cycle period, and the length that maximized power output was 10% longer than the in vivo operating length.