Description: 

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.

Transcription: 

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. 

Questions: 

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?