Explaining how ladybirds fold their delicate flying wings could inspire lightweight but strong flexible structures
Collapsible structures have many applications, particularly in spacecraft, where the ability to fold structures like antennae and solar panels into a small volume for launching but still have it unfold once deployed into a strong, rigid structure is invaluable. Nature, as so often, provides inspiration, and insects are the undoubted masters of this trick, with lightweight wings that can collapse and fold into small spaces and yet unfold into structures stiff and strong enough to support and propel the animals in flight.
Researchers at the University of Tokyo have now uncovered how ladybirds (locally known as ladybugs) stow their wings. These particular common beetles were chosen because of the speed with which they can unfold and deploy their wings.
Like most beetles, ladybirds have two sets of wings. The forward set, called elytra, are a hard material and act as protection for the more delicate underling rear set which the insect uses for flying. The Tokyo team, led by Professor Kazuya Saito of the university’s Institute of Industrial Science, wanted to investigate the roles played by unusually complex origami-like folds in the wings, thick veins in comparison to their size, and up-and-down motions of the insect’s abdomen that had been observed previously.
One problem was that the folding of the rear wing is connected to the opening and closing of the elytra. To get around this problem, the team anaesthetised a ladybird, removed one elytron and cast a replica of it from transparent resin – the same kind used in fingernail art. They then stuck this transparent elytron onto the stub of the removed wing-case and observed the insect using high-speed cameras and micro-CT scanning. “I wasn’t sure if the ladybug could fold its wings with an artificial elytron made of nail-art resin,” said Saito. “So I was surprised when I found out it could.”
The team found that the insects use the edges and lower surfaces of the elytra to guide the folding of the underwing, which happens mostly after the elytra are closed. The CT scanning revealed that the veins in the wings have a curved shape similar to that of a steel retractable measuring tape (also known as a tape spring) that give rise to rigid points in the wing which can become flexible, and along which the wing can fold up. “The ladybugs’ technique for achieving complex folding is quite fascinating and novel, particularly for researchers in the fields of robotics, mechanics, aerospace and mechanical engineering,” said Saito.
In a paper in the journal Proceedings of the National Academy of Sciences, Saito and team explain how this discovery could have implications for the design of robots, elements of buildings and lightweight collapsible structures
I find these articles fascinating and very useful for stimulating ideas on approaches to engineering projects. What trips my brain cell though is the sheer unbelievable complexity of coding required for the manufacture of the structures as an integrated whole system with control “firmware” pre-installed and running! So easy to overlook how utterly amazing even these common insects are.
I agree: but Nature has had billions of years, eons! [now there’s an interesting name, the same as my electricity supplier?] of time to get the design right via natural selection? And just like many parts of the earliest cathedrals/castles/Parliaments which certainly often fell down before the arch-technicians (we call them architects) got it right by trial and error (there was not a lot of differential calculus around in the 13th century) presumably there are many branches of biology and zoology which led to dead (literally) ends!
The more I think about it, I still don’t know what would drive the huge mutation rate required to come up with viable functional structures with the correct build instructions for every molecule to go to the correct place at the correct time which would have to include assembling all the control muscles and nerves, blood supply etc etc etc. I understand there are error correction mechanisms in the dna machinery to prevent errors – and what prevents sods/murphy’s law from operating as quick as it normally does 😉 As anybody that has to make something that really does actually work knows, there are many more ways of making something that accidentally doesn’t work compared to ways that do work. There must be a world of useful manufacturing technology waiting to be decoded in the dna – absolutely fascinating and looking forward to reading what scientists manage to discover in future.