EFFICIENT BUTTERFLY FLIGHT reported in BBC News 20 January 2021, ScienceDaily 21 January 2021 and Journal of The Royal Society Interface 20 January 2021 doi: 10.1098/rsif.2020.0854. Two researchers at the Swedish Lund University have studied the fluttery flight of butterflies, which has been traditionally considered ungainly and inefficient. Per Henningsson and Christoffer Johansson commented in their report: “Butterflies look like no other flying animal, with unusually short, broad and large wings relative to their body size”. Henningsson and Johansson analysed the flapping flight of butterflies taking off in a wind tunnel and found their flight was very efficient due to having flexible wings and using a “clap technique”. During the upstroke of the wingbeat the flexible wings form a cup shape that traps a pocket of air. At the top of the upstroke the wings clap together forcing the air out backwards, which propels the butterfly forward. The downstroke of the wingbeat is then “used for weight support”, i.e. it keeps the butterfly in the air. Henningsson and Johansson confirmed the flexible wings and clap technique produced efficient flying by designing and building similar mechanical winged drones and testing them in the wind tunnel. They found “flexible wings dramatically increase the useful impulse (+22%) and efficiency (+28%) of the clap compared to rigid wings”. The researchers suggest the large wings and clapping technique gave them an evolutionary advantage by being able to escape quickly from predators. Per Henningsson told the BBC: “It’s a strong selective pressure then, because it’s a matter of life and death”. The researchers concluded: “Combined, our results suggest butterflies evolved a highly effective clap, which provides a mechanistic hypothesis for their unique wing morphology. Furthermore, our findings could aid the design of man-made flapping drones, boosting propulsive performance”.
Link: ScienceDaily
ED. COM. Creation Research. Escaping from predators will certainly give butterflies a selective advantage but it won’t make anything evolve. Butterflies that already had such efficient flight didn’t need to evolve. Selection can only eliminate the unfit. It cannot make anything unfit turn into something more fit.
Notice the inconsistency in the researchers’ conclusion: butterflies “evolved” their unique wing shape and efficient clap technique, but man-made flapping drones with the same flying ability will have to be designed and built by intelligent engineers. These researchers, who created their flapping model drones to test in the wind tunnel, are without excuse for failing to recognise the Creator of the natural butterflies, which are not only very efficient but more beautiful and do other things besides fly. Whenever you see a butterfly fluttering give praise the Creator who made it to fly efficiently, fertilise flowers and bring joy to people who see it. |
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