This film shows two aerial righting maneuvers of a dragonfly. The first occurs by design in our experiment, and the second is a surprise.
When released upside-down in the air, a dragonfly responds within 100ms to execute a rolling motion to right itself [1,2]. In these experiments, we release dragonflies from a magnetic tether to elicit this recovery maneuver for further analysis. The behavior seems to be a hard-wired reflex. Different dragonflies perform similar rolling maneuvers if starting from similar initial conditions.
How and why did dragonflies acquire such aerial skills? The second maneuver provides a clue. Towards the end of the film, as the dragonfly approaches a wall, it appears to be startled, quickly decelerating, colliding with the wall, and finding itself in an upside-down orientation again. To recover, it performs a similar rolling maneuver as seen earlier. Such encounters and collisions with an object may be one of many scenarios that forced dragonflies to practice and perfect aerial righting throughout their long evolutionary history.
1. James Melfi Jr., Anthony Leonardo, Z. Jane Wang, APS-DFD Gallery of Fluids, 2014
2. Z. Jane Wang, James Melfi Jr., Anthony Leonardo, `Dragonfly Righting Reflex', in revision.
ZJW thanks Simons Fellowship in Mathematics, Center for Computational Biology at Flatiron Institute, and Applied Mathematics Lab at Courant Institute, NYU for support during these experiments in summer 2021.