Dragon-drop The passive mechanism and active control of the dragonfly’s aerial righting behaviour


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


94-1  Sat Jan 2  Dragon-drop: The passive mechanism and active control of the dragonfly’s aerial righting behaviour Fabian, ST*; Zhou, R; Lin, HT; Dept. of Bioengineering, Imperial College, London; Dept. of Bioengineering, Imperial College, London; Dept. of Bioengineering, Imperial College, London s.fabian@imperial.ac.uk http://www.samueltfabian.com

Dragonflies (Anisoptera) are capable of extreme performance and demonstrate this in predatory and conspecific interactions on a daily basis. We might presume that the manoeuvrability required for such feats would inherent instability necessary for rapid, active control. To test the ability of dragonflies to react to an undesirable flight state, we dropped common darter dragonflies (Sympetrum striolatum) from a range of orientations and used precise micro motion-capture technology to measure the movements of their head, thorax and abdomen as they regained a normal flight-attitude. We conducted inverted drops in darkness, demonstrating that dragonflies are still capable of righting without visual input. By dropping anaesthetised dragonflies, we found that dragonflies passively enter a stable dive but must react to regain a suitable pitch. Pitch control was managed in collaboration with movement of the abdomen relative to the thorax. We isolated distinct righting behaviours across the different conditions that formed the basis of active righting, the use of which differentiated the animal’s righting reflex from purely passive stability. We concluded that the wing posture gives dragonflies a level of passive flight stability which may simplify some complex aerial tasks. Finally, mechanosensation alone is sufficient to maintain all the basic flight control while vision enables tasks specific control and adds robustness.

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