The Fascinating World of Structural Coloration in Animals

When we think of animal colors, pigments often come to mind. However, some of the most vibrant and iridescent colors in nature are not due to pigments but rather to structural coloration. This phenomenon occurs when microscopic structures interfere with light, creating stunning visual effects. Let's explore a few examples of animals that exhibit this remarkable trait.

This new article published by the royal society contains some of the latest research on the colouration in butterfly wings discovered through electron microscopy techniques.

Elucidating nanostructural organization and photonic properties of butterfly wing scales using hyperspectral microscopy Anna-Lee Jessop†, Primož Pirih†, Limin Wang, Nipam H. Patel, Peta L. Clode, Gerd E. Schröder-Turk and Bodo D. Wilts

https://doi.org/10.1098/rsif.2024.0185

Butterfly Wings

Butterflies are famous for their colorful wings, but not all of these colors come from pigments. For instance, the brilliant blue of the Morpho butterfly is due to microscopic scales on its wings that reflect and refract light, creating an iridescent effect².

Beetle Wings

Many beetles, such as the jewel beetle, display metallic colors that are also a result of structural coloration. The intricate layers of their exoskeletons reflect light in such a way that it creates shimmering, iridescent hues².

Peacock Feathers

The peacock's tail feathers are another classic example. The vibrant blues and greens are produced by microscopic structures that interfere with light waves, rather than by pigments². This structural coloration makes the feathers appear different colors when viewed from different angles.

Fish Scales

Certain fish, like the neon tetra, have scales that reflect light to produce bright, iridescent colors. These colors can change depending on the angle of the light and the viewer's perspective².

Bird Feathers

Birds such as hummingbirds and kingfishers also exhibit structural coloration. Their feathers contain microscopic structures that refract light, creating vivid and often iridescent colors³.

Mechanism of Structural Coloration

Structural coloration occurs through several mechanisms, including:

• Diffraction Gratings: Microscopic grooves that split light into its component colors.
• Photonic Crystals: Structures that reflect specific wavelengths of light.
• Thin-Film Interference: Layers of material that cause light waves to interfere with each other, enhancing certain colors and canceling others.

These mechanisms can work alone or in combination to produce the dazzling array of colors seen in nature.

Conclusion

Structural coloration is a fascinating natural phenomenon that adds to the beauty and diversity of the animal kingdom. From butterfly wings to peacock feathers, these colors are a testament to the intricate and wondrous ways in which nature operates.

Source: Conversation with Copilot, 15/09/2024 (1) Structural coloration - Wikipedia. https://en.wikipedia.org/wiki/Structural_coloration. (2) How Birds Make Colorful Feathers | Bird Academy • The Cornell Lab. https://academy.allaboutbirds.org/how-birds-make-colorful-feathers/. (3) Animals only see in black and white and 5 other color myths. https://www.popsci.com/science/color-myths/. (4) en.wikipedia.org. https://en.wikipedia.org/wiki/Structural_coloration.