This video will make you believe in magic.
The beginning of a butterfly is wonderful. Gently nestled in its cocoon, a caterpillar transforms into an angel-like creature with carefully placed iridescent scales on each wing. Piece by piece, scientists are putting together how the magic of that metamorphosis happens. And they have just opened another step: the formation of scale.
Peeking straight into the chrysalis of a morphing caterpillar — on its way to becoming a painted female butterfly — a group of scientists at the Massachusetts Institute of Technology recorded the insect’s scales during its transformation. The shocking footage and featured photos were published in the PNAS Journal on Monday.
But butterfly wings are more than just beautiful. Understanding their plans could ultimately benefit manufactured materials such as windows and thermal systems and even bring an ethereal quality to textiles.
“Previous studies provide compelling snapshots at select stages of development; unfortunately, they do not reveal a consistent timeline and sequence of what happens as scale structures grow,” said an associate professor of mechanical engineering at MIT and co-author of the study. study author Mathias Kole, said in a statement. “We need to see more to understand this better.”
First, the researchers carefully cut a caterpillar’s paper-thin chrysalis as its transformation began. They then peeled off a cuticle, or covering, of the developing wing and exposed the budding scales underneath. Jackpot.
But to protect the soon-to-be butterfly, they put a transparent cover over the incision. That way, the caterpillar can develop naturally, while the team maintains a spectacular view.
“This paper focuses on what’s on the surface of a butterfly wing … engineering and lead author of the study, notes,” said Anthony McDougall, a researcher in MIT’s Department of Mechanical Engineering and lead author of the study. and on the surface, scales are forming.”
“We can imagine all of this – which is really beautiful to look at.”
To isolate the translucent scale structures, the team used a “spotted area” to highlight every airy, colorful layer. Instead of employing a classic light beam, which widens and can damage scales via UV radiation, they shone tiny specks of light at specific points.
“The speckled area is like a thousand fireflies that generate a field of dots of light,” said Peter So, a professor of mechanical engineering and biological engineering at MIT. “Using this method, we can isolate the light coming from different layers, and reconstruct the information, efficiently, to map a structure in 3D.”
While there is a bunch of noise in the footage, mainly around the edges of the scales in the top left, the stages of scale development were easily visible. Within days, the cells began to line up and organize themselves in a shingle-like pattern, where some were buried under others.
As they grew, they formed their own distinctive ridges in unexpected ways. Instead of gradually wrinkling into an accordion shape—as the researchers suspected—the scales suddenly wavered. The group hopes to delve more closely into the precise mechanisms of ridge formation in future projects.
McDougall said, “Many of these phases were previously understood and observed, but now we can piece them all together and continuously observe what’s going on, which gives us a detailed understanding of how the scale is going.” are made.”
from story to reality
Beyond their mystical appeal, butterfly wings are fascinating because they offer a perfect blueprint for many man-made objects; His scales, in particular, boast some utilitarian traits.
For one, the team says the complex architecture helps the insect cool down when it’s hot and shed moisture along its ridges on rainy days. But perhaps most remarkably, the scales take advantage of a concept called structural color to emit color without any pigment.
Unlike standard pigments or dyes, which absorb or reflect particular wavelengths of electromagnetic radiation and emit the corresponding color, structural dyes do not depend on chemical composition. Instead, physical composition is important.
On the wings of a butterfly, each scale is placed in such a way that the light is scattered conspicuously; Our eyes acquire a specific color associated with that scattering. That’s why some bright insects appear to change color at different angles.
Structural paint has already inspired a few different products, such as this durable gloss invented by researchers hoping to reduce the use of microplastics. “This strategy can be used, for example, to give both color and self-cleaning properties to automobiles and buildings,” McDougall said. “We can now learn from butterflies the structural control of these complex, micro-nanostructured materials.”
As it turns out, butterflies’ wings aren’t just exquisite. They’re made from gravely scales that are the closest we can have to fairy dust.