Wings and halteres act as coupled dual-oscillators in flies

The mechanics of Dipteran thorax is dictated by a network of exoskeletal linkages which, when deformed by the flight muscles, generate coordinated wing movements. In Diptera, the forewings power flight, whereas the hindwings have evolved into specialized structures called halteres which provide rapid mechanosensory feedback for flight stabilization. Although actuated by independent muscles, wing and haltere motion is precisely phase-coordinated at high frequencies. Because wingbeat frequency is a product of wing-thorax resonance, any wear-and-tear of wings or thorax should impair flight ability. How robust is the Dipteran flight system against such perturbations? Here, we show that wings and halteres are independently-driven, coupled oscillators. We systematically reduced the wing length in flies and observed how wing-haltere synchronization was affected. The wing-wing system is a strongly-coupled oscillator, whereas the wing-haltere system is weakly-coupled through mechanical linkages which synchronize phase and frequency. Wing-haltere link acts in a unidirectional manner; altering wingbeat frequency affects haltere frequency, but not vice-versa. Exoskeletal linkages are thus key morphological features of the Dipteran thorax which ensure wing-haltere synchrony, despite severe wing damage.

Methods
This data was collected as part of experiments to test the mechanical coupling of wing and halteres in flies for the paper "Wings and halteres act as coupled dual-oscillators in flies", DOI: 10.7554/eLife.53824. Wing and haltere frequency and amplitude were computed from high speed videos of tethered soldier flies after a series of mechanical perturbations. Please find details of the data organization in the usage notes as well as the relevant readme file within the dataset. The code database to generate this data can be found at https://github.com/TanviDeora/Coupled_dual_oscillators_DeoraSaneSane.