Dynamics of body kinematics of freely flying houseflies responding to air turbulence

Abstract

From the world's tiny flying bugs to gigantic dobsonflies, inflight locomotion of a flying creature requires complex biomechanical strategies to cope with air turbulence. These unpredictable changes in ambient airflow strength and direction may destabilize body posture and orientation. To record this behaviour in further detail, we scientifically examined how houseflies (Musca domestica) respond to air turbulence. We then, three-dimensionally reconstructed body and wings motion of continuously perturbated houseflies using high-speed videography under laboratory condition. The findings confirmed that houseflies, in general, do not initiate flight when average ambient air speed exceeds ~0.63 ms−1 at approximately ~2% of relative turbulent intensity. This finding contrasts with flies which immediately take-off after being released. During mild turbulent conditions, flies performed take-off but with severe and active modulation of body postures. In addition, the body roll angle fluctuates more severely (18.5-fold increase) compared to yaw (7-fold of increment) and pitch (6.4-fold of increment) during turbulence, highlighting that body roll stability is highly sensitive. This research extends our current knowledge on flies' behaviours during turbulence and how insects achieve their superior flight performance.