Meeting Abstract
Flying insects are known to control orientation via torques arising from at least three distinct affordances: by varying aerodynamic center of pressure, by changing body posture to alter center of mass location, and by swinging body segments or limbs to exert inertial torques. Each affordance is subject to distinct constraints, saturations, and sensitivities, as potential coupling to the control of center of mass forces (e.g. vertical support). We hypothesize that these sources of control are integrated in parallel to increase robustness and agility, are weighted according to behavioral context, and are tuned to body morphological parameters. To investigate affordance integration in flight, we built an actuated armature to apply rapid pitch movements to a tethered flying moth, Manduca sexta, while measuring the torque exerted by the moth’s flight forces and body movement. Closing the loop between measured torque and applied movement enables control of the forces experienced by the moth while allowing pitch movement (e.g. a haptic environment); a video screen enables visual experience to either match mechanosensory experience or be rotated with the moth to provide sensory conflict (e.g. a virtual reality environment). We used our device to apply short perturbations and examined the magnitude of torques arising from each affordance. Body kinematics were recorded with a high-speed camera and combined with morphometric data to estimate inertial torques and center of mass motion associated with abdominal flexion. These estimates were combined with measurements of total pitch axis torque to estimate the torque generated by the three affordances during the perturbations. Moths appear to employ parallel strategies to generate torques counter to the perturbations, consistent with a stabilizing response.
