Engineers from the Massachusetts Institute of Technology (MIT) shared a stunning video of how butterfly wings are formed as they undergo metamorphosis. The scales in the butterfly wings give them color and shimmer as well as protect them against harmful elements.
The experts said that the findings could serve as a blueprint in developing new materials for applications involving iridescent windows and waterproof textiles.
Painted lady butterfly from Spain
MIT Engineers Raised Painted Lady Butterflies
MIT mechanical engineer Dr. Anthony McDougal explained that butterflies precisely form the structural architecture of their wing scales to control their wing attributes. According to the Daily Mail, their observations helped them learn how these complex, micro-nano structured materials form into butterfly wings.
In their study published in the Proceedings of the National Academy of Sciences (PNAS), researchers raised painted lady caterpillars (Vanessa cardui) in individual containers until they pupate. This butterfly species was chosen because it has wings that are common across most butterfly species.
Once each butterfly are encased in their chrysalis and started to undergo metamorphosis, the team carefully cut into it and peeled away a small square, and filled the vacant space with a transparent window to let them look in on the developing wing of the butterfly.
Lastly, they used the "speckle-correlation reflection phase microscopy" imaging method to observe the development of the wings. This works by shining numerous small points of light across the area of the wings and measuring each reflected to create the map of the subject.
The experts explained that the speckle field does not risk harming the delicate cells of the pupa because it was like thousands of fireflies generating a field of illumination points that allow them to observe the natural process of butterfly wings developing.
Also, this enabled them to isolate the light coming from different layers so they can reconstruct the information to efficiently map the structure in 3D.
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How Do Butterfly Wings Form?
ARS Technica reported that the video footage MIT engineers shared revealed how cells started lining in rows within days since the metamorphosis began.
Experts explained that cells started differentiating and forming an alternative pattern of scales overlaying wing and some growing underneath. At the last stage, long, thin, and grooved ridges similar to a tiny version of corrugated roofing were formed as a result of compression.
The team assumed that compression enabled the ridges to form as scales kept growing, which suggests that it is a different mechanism of work than shrinking.
"A lot of these stages were understood and seen before, but now we can stitch them all together and watch continuously what's happening, which gives us more information on the detail of how scales form," McDougal said in the press release.
They clarified that the study only focuses on the surface of butterfly wings and not what is within. Nonetheless, they observed underneath connections that communicate to the surface as cells organize and scales start to form.
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