Asynchronous haltere input drives specific wing and head movements in Drosophila

Halteres are multifunctional mechanosensory organs unique to the true flies (Diptera). A set of reduced hindwings, the halteres beat at the same frequency as the lift-generating forewings and sense inertial forces via mechanosensory campaniform sensilla. Though haltere ablation makes stable flight impossible, the specific role of wing-synchronous input has not been established. Using small iron filings attached to the halteres of tethered flies and an alternating electromagnetic field, we experimentally decoupled the wings and halteres of flying Drosophila and observed the resulting changes in wingbeat amplitude and head orientation. We find that asynchronous haltere input results in fast amplitude changes in the wing (“wing hitches”), but does not appreciably move the head. In multi-modal experiments, we find that wing and gaze optomotor responses are disrupted differently by asynchronous input. These effects of wing-asynchronous haltere input suggest that specific sensory information ..., High speed videos were recorded at 750-2000FPS from tethered, flying Drosophila using high speed cameras (TS4 or IL5, Fastec Imagining, San Diego, CA, USA). Haltere kinematics were extracted using the DeepLabCut python package (Mathis et al. 2018, Nature Neuroscience) or the DLTdv package (Hedrick 2008,  Bioinspiration and Biomechanics). Concurrent videos recorded at 100FPS using an industrial machine vision camera (Point Grey Chameleon3, FLIR, Wilsonville, OR, USA) provided head yaw and wingstroke envelope measurements computed using flyalyzer (https://github.com/michaelrauscher/flyalyzer), a custom MATLAB (The Mathworks, Natick, MA, USA) program., Dataset includes extracted kinematic timeseries in *.mat format, which is readable by MATLAB and the freely-available OCTAVE software (https://www.gnu.org/software/octave/index). Included README files provide details about fields in each data file Included analysis scripts were written with MATLAB 2021b and should function with this and subsequent versions., \"treatedkinematics.mat\" contains aggregated haltere tracking data from high-speed lateral aspect videos. It contains the \"flies\" structure array with the following fields: haltroot: [x,y] point within video frame marking haltere joint with the thorax wingroot: [x,y] point marking the most anterior point in the wing root treatment: LEFT or RIGHT depicts which haltere is treated with an iron filing vstim: Voltage trace from arena controller showing angular position of the stripe stimulus in the yaw aspect (where applicable), with original daq sampling rate vspeed: Pattern velocity of visual stimulus in /s, or 0 for no moving visual stimulus magstim: Voltage trace from DAQ for control pulses sent to magnets (where applicable), with original daq sampling rate magepoch: Vector labeling time indices with magnetic stimulation applied at that time. 36Hz trials are erroneously labeled as 37Hz. 72Hz trials erroneously labeled as 75Hz trials. onstartix: Manually-annotated video frame indices mark...