Meeting Abstract

84.5  Monday, Jan. 6 11:30  Wings wobble when waggled: detecting Coriolis forces from bending dynamics EBERLE, AL*; DICKERSON, BH; REINHALL, P; DANIEL, TL; Univ. of Washington; Univ. of Washington; Univ. of Washington; Univ. of Washington eberle10@uw.edu

Insect wings are flexible structures that are subject to Coriolis forces when they experience rotational motions in an axis orthogonal to their flapping axis. Since insect wings are richly imbued with mechanosensors, they can potentially act as detectors of body dynamics like the halteres of dipteran flies. Indeed, recent behavioral, electrophysiological and anatomical evidence suggests that the wings serve a gyroscopic function, mediating reflexes to body rotations. But, can Coriolis forces be detected using only changes in the structural dynamics of a flapping flexible wing? To address this question we built a robotic actuator that rotates a flapping model wing about an axis orthogonal to the axis of wing flapping. Using a wing with a flexural stiffness of similar to Manduca sexta wing, we took high-speed video of the model wing flapping at a frequency similar to that of Manduca (25 Hz). We compared the 3D structural dynamics of flapping wings with and without a 3 Hz, 20 degree, rotation about the yaw axis. We observed a large difference in tip displacement induced by the body rotation, with a maximum of approximately a 30% decrement in the amplitude of tip displacement at both wingbeat frequency and twice wingbeat frequency (systematic error of measured position is approximately 1 mm). These results are consistent with the influence of Coriolis forces. In addition, our observed changes in tip displacement indicate similar changes in strain over the surface of the entire wing. Moreover, in the context of a Manduca wing, the strains could stimulate embedded mechanoreceptors at the wing base and over the surface of the wing that could trigger reflexive responses to body rotations.