Meeting Abstract

73.1  Monday, Jan. 6 08:15  Closing the loop on abdominal control with free flight pitch perturbations DYHR, JP*; SPONBERG, S; HALL, R; COLMENARES, DJ; CHAUHAN, NS; DANIEL, TL; Univ of Washington; Univ of Washington; Univ of Washington; Carnegie Mellon Univ.; Univ Prep HS; Univ of Washington jdyhr@u.washington.edu

Flying animals use multiple motor outputs for flight control. While the aerodynamic force generation by wings has been of primary interest, changes in body shape have also been shown to contribute to flight stabilization in the hawkmoth Manduca sexta. This inertial control mechanism acts to both modulate the center of mass relative to the centers of lift and thrust and to redirect the vectored forces produced by the wings. However, the extent to which inertial control is used to stabilize flight has been inferred from experiments in tethered flight preparations, greatly altering the body dynamics of the animal. Here, we ask whether moths use abdominal movements for control in free flight and compare our results to those from open-loop tethered flight experiments. To accomplish this we used high-speed videos of moths feeding from a robotically actuated flower. The flower was rotated about the pitch axis, forcing the moth to track that motion to continue feeding. By varying the pitch angle using a broadband sum of sines trajectory, we were able to determine the sensorimotor transfer function between flower motion and abdominal-thoracic angle. We show that movements of the abdominal-thoracic joint are strongly coupled to the visual stimulus and that the shape of the response is consistent with a high-pass filter with a 3 dB cutoff frequency at approximately 2 Hz with a fixed time delay of 200 ms. These free flight responses are similar to those responses observed in tethered open-loop studies.