ALIVE OR DEAD, THEY ARE FLIPPING GOOD AT IT! Dragonfly backflips described in articles in ScienceDaily 9 February 2021, Imperial College London news 10 February 2021, and PNAS 10 February 2021 doi: 10.1098/rspb.2020.2676. Dragonflies are noted for superb aerial manoeuvres, including flying backwards, but even the most agile flyer can be knocked off balance or flipped upside down. A group of scientists at Imperial College London studied common darter dragonflies to see how they could right themselves after being dropped in an upside-down position. They found the dragonflies righted themselves with a head-first backwards somersault. Anaesthetised (unconscious) dragonflies also did the same backflip, but were slower. Not surprisingly “dead dragonflies did not perform the manoeuvre at all”. However, when researchers used wax to fix wings of the dead dragonflies into the same position as the unconscious dragonflies the dead dragonflies righted themselves, albeit in a slightly more ungainly way. These results led researchers to conclude that the righting process is mainly a passive result, dependent on wing position and muscle tone (live or dead). Samuel Fabian of the Department of Bioengineering commented: “Planes are often designed so that if their engines fail, they will glide along stably rather than drop out of the sky. We saw a similar response in dragonflies, despite the lack of active flapping, such that some insects, despite their small size, can leverage passive stability without active control.” He went on to say: “Passive stability lowers the effort requirements of flight, and this trait likely influenced how dragonfly shapes evolved. Dragonflies that use passive stability in flight are likely to have an advantage, as they use less energy and are better able to recover from inconvenient events.” The researchers concluded: “This lesson from biology can inspire design principles for failsafe attitude recovery in micro aerial systems.”
Links: Imperial College, ScienceDaily
ED. COM. If aerodynamically stable aeroplanes need to be designed so they don’t drop out of the sky, why would anyone believe that aerodynamically stable dragonflies evolved the same characteristic by chance random processes? Particularly when they are dead. Passive stability is certainly an advantage once a dragonfly has it, but, as the experiments with dead dragonflies show, there is only one chance to get both muscle tone and wing position right. Otherwise flipped over dragonflies would drop out of the air and not get any chance to evolve. These experiments are further proof that design is the only way to fly. If you ever had the misfortune to be in an aircraft whose engines failed you would give thanks to the engineers who built a failsafe glide into the design to get it safely back on the ground. Therefore, the lesson to be learned from biology is there is no excuse for failing to give thanks to the Creator Christ for designing wonderful flying creatures like dragonflies that can keep themselves flying even when flipped and dropped.
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