Meeting Abstract

101.1  Sunday, Jan. 6  How the hawkmoth Manduca sexta moves left and right GREETER, JSM*; HEDRICK, TL; Univ. of North Carolina at Chapel Hill jgreeter@live.unc.edu

Understanding flight control strategies in insects is essential for drawing a complete picture of the evolutionary and biomechanical underpinnings of flapping flight. Many flying animals can produce lateral “sideslip” maneuvers, which we investigate here in the moth Manduca sexta. We elicit maneuvers using phototaxis, whereby moths follow an oscillating low-intensity light source in a dark flight chamber. We measure angular and translational kinematics of the moth body and wings in flight with high-speed 3D videography. Our data show that sideslipping moths roll to redirect their body-weight lift vector, a reorientation which is sufficient to produce the lateral accelerations we observe. Using wingtip position, rather than body position, to calculate roll angle produces the strongest relationship between roll and lateral acceleration. Thus moths can, to some extent, actuate their wings independently of body roll. Still, larger lateral accelerations require whole-body roll in addition to wing stroke changes. Among the many possible ways to create roll acceleration, moths produce left-right wing asymmetries in both sweep amplitude and long-axis rotation angle. Conceptually, asymmetries in both quantities create yaw and roll torques. Preliminary data support a scenario in which a moth producing a roll to the right during upstroke alters its long-axis rotation angle so as to reduce the angle of attack of its left wing relative to that of its right. This angle of attack asymmetry also creates a yaw-left torque. The moth counters this yaw torque by increasing the relative sweep amplitude of its left wing during that upstroke and/or decreasing the relative sweep amplitude of its left wing during the subsequent downstroke.