What does it mean to be blue? The wings of a Morpho butterfly are some
of the most brilliant structures in nature, and yet they contain no blue pigment
they harness the physics of light at the nanoscale.
What does it mean to be blue? The wings of a morpho butterfly are some
of the most beautiful structures in nature, and yet they contain
no blue pigment. Artists use paint, dyes and ink to make their creations.
Nature draws on a palette of biological
pigments also known as biochromes. But there's another way of producing color.
It's called "structural color." And it harnesses the physics of light at the nanoscale.
Nipam Patel's lab at UC Berkley is studying how morpho butterflies form
the specialstructures that cover their wings - scales - while still inside the pupae.
Morphos live mostly in the tropics.When resting, they fold their wings up,
showing their dark earth-toned undersides. The brown, yellow and black
colors are generated by pigments. But the other side is all about structural color.
It gives their wings a vibrant, iridescent blue hue.
Each scale is like a pixel, a tiny tile in a larger mosaic in layers of
overlapping rows. Researchers want to see how structural color takes
shape on the wings, but normally this happens inside
the pupae, which is opaque. So they've figure out how to remove the morpho
wings from the pupae and grow them in a Petri dish.
Just like a developing photograph,patterns and colors slowly
appear on the ghostly white wings as each scale's surface
transforms over time. Ridges on the scales' surface are a key component that
affect how the wings spreads - or refracts - light, similar to a prism.
When lights hits these ridges, a phenomena called constructive
interference comes into play.
The spacing with the ridges - which look like little Christmas trees - perfectly
reinforces specific wavelengths while canceling out others.
This is why your eyes perceive that shimmering blue.
Scientist aren't sure why but vertebrates and plants rarely produce
blue as a pigment. For some reason, it's a pigment
you don't see much of in nature.
So think of structural color as an evolutionary work-around- a way
of producing brilliant blues at a nano level. Not just on
butterfly wings but on feathers, beetles, even our own bodies.
1. What makes a morpho butterfly unique and beautiful?
2. What are biochromes? What is a structural color?
3. Aside from butterflies, what other things use the structural colors?