Researchers at the University of Tokyo constructed a transparent artificial forewing and transplanted it on a spotted ladybug to study the folding motion using high speed cameras.
Researchers have discovered the folding mechanism of ladybug wings using high speed cameras.
They found that ladybugs have curved ‘crease line’ shapes in their hindwings veins, much like carpenter’s tape, to help support the wings and make them bendable.
The discovery of this technique could be useful for engineers for developing structures ranging from satellite antennas and aircraft, to microscopic medical equipment and even articles for daily use like umbrellas and fans.
Researchers at the University of Tokyo used high-speed cameras to study the wing folding mechanism of spotted ladybugs
Ladybugs are highly mobile insects that can switch between walking and flying easily because of how quickly they can deploy and collapse their wings.
Their wings consist of two stuctures: Forewings called elytra – the hard, red structure with spots that covers the hindwings, soft-membrane wings that are used for flight and covered and protected by the elytra when they’re not flying
Previous studies suggested that up-and-down movements in the abdomen and complex origami-like crease patterns on the wings play an important role in the folding process, but how the simple folding motion produces such an intricate folding shape was a mystery.
Ladybugs close their elytra before folding their wings, making it difficult to observe the process – but they also can’t be removed to reveal what’s underneath as they’re essential for folding.
So to better study the folding mechanism, researchers based at the University of Tokyo constructed a transparent artificial elytron from ultraviolet light-cured resin, which is often used in nail art, and transplanted it on a spotted ladybug (Coccinella septempunctata) using a silicon impression of an elytron they removed from the ladybug.
The researchers then used high-speed cameras to observe the hindwing’s folding and unfolding movements.
They found that ladybugs use the edge and lower surface of the elytron, whose curvature fits the curve shape of the hindwing veins, to fold the wings along crease lines, together along with abdominal lifting movements, which leads to the rubbing and pulling of the hindwings into the storage space on their backs.
‘I wasn’t sure if the ladybug could fold its wings with an artificial elytron made of nail-art resin, ‘ said Dr Kazuya Saito, Assistant Professor of Tokyo’s Institute of Industrial Science and the lead author of the study.
‘So I was surprised when I found out it could.’
The researchers also used micro computed tomography scanning (CT) – an imaging technique that uses x-rays to create cross-sections of a physical object – to investigate the 3D shapes of folded and unfolded wings, and bending points in the rigid area of the soft hindwings to understand how they transform from being rigid and strong for flying, to elastic and foldable.
They found that a curved shape in the veins, similar to carpenter tape, helps support the wings.
Similar tape spring-like structures – strong and firm when extended, but which can be bent and stored in compact form – are widely used in extension booms and hinges of space deployable structures like satellite antennas.
‘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 Dr Saito.
