COMBES, S.A.*; LONGNION, J.K.; DANIEL, T.L.; Univ. of Washington, Seattle; Univ. of Washington, Seattle; Univ. of Washington, Seattle: Abdominal flexion and maneuvering flight in hawkmoths

Maneuvering flight involves a number of control surfaces, including the wings, head, legs, and abdomen. For example, many insects display strong abdominal flexion during flight, associated with corrective steering behavior, predator avoidance, and other flight maneuvers. In tethered hawkmoths (Manduca sexta), we find that visual field motion elicits vertical abdominal flexion, which is sensitive to the velocity of the visual stimulus. We show that these abdominal movements alter the location of the center of body mass, and perform static analyses to demonstrate that the resulting torque could produce rapid body rotations. To examine the role of abdominal flexion during free flight, we use high-speed videography to record free flight maneuvers. We find that hawkmoths display vertical abdominal movements associated with each wingstroke, as well as longer-term adjustments in abdominal flexion over a number of wingstrokes. These longer-term changes in abdominal flexion are highly correlated with body angle, which varies from below 25 to over 75 degrees from the horizontal during maneuvering flight. We use a dynamic analysis to explore how the observed changes in abdominal flexion affect body angle, and analyze flight trajectories to explore the relative roles of abdominal flexion and wing kinematics during maneuvering flight. (support: ONR, NSF, Packard Foundation)