OSCILLOSCOPIC AND STROBOSCOPIC ANALYSIS OF THE FLIGHT SOUNDS OF DROSOPHILA

Abstract

Oscillographic records are presented of sounds produced by P. funebris during "fixed" flight. Strobo-scopic detns. of wingbeat frequency indicate that 1 cycle of wing motion corresponds to 1 cycle of flight sound. The sounds generated during flight are complex and differ radically from the simple harmonic motion of a tuning fork. Certain consequences are discussed. Analysis of these sounds suggests a remarkable aerodynamic efficiency for the wingbeat cycle. There is a polarized flow of air from front to rear during approx. 85% of the wingbeat cycle. During brief periods of flight the 1st few and the last few beats of the wings are accomplished at the high frequency characteristic of the entire flight. This fact is considered in relation to Pringle'' s new observations concerning the neuromuscular system of dipterous insects.