Butterfly Wings: how they get their colors, and what they’re used for
By: Katrin Gross
If you’ve ever seen a butterfly, you probably know how beautiful and colorful they are. Butterflies have a hugely diverse array of colorful wing patterns ranging from bright blues and rich reds to spots and stripes. But why do butterflies have these beautiful wings? Where do these colors come from?
Many butterflies use their wing patterns and colors for self defense. Some butterflies with more neutral colored wings–involving lots of browns and greens–can hide from their predators by blending into their surroundings, using a defense mechanism called camouflage. For example, the underside of the wings of an Oakleaf butterfly look like a dead leaf, which isn’t very appetizing to predators. Other butterflies use their wings to confuse and scare away their predators. They can have vibrantly colored wings that warn predators that they are poisonous. For example, monarch butterflies have beautiful orange wings for this very reason. Even non-poisonous butterflies can take advantage of this by using their colorful wings to mimic other poisonous insects. For example, non-poisonous Viceroy butterflies copy the coloration of Monarch butterflies so that predators think they are poisonous too.
But you may be wondering, how do butterflies get their multicolored wings?
Some butterflies get their colors from pigments. Pigments are what we usually think of when we think of color–they are chemicals that absorb some colors of light and reflect others. The colors that they reflect are the colors that we see. We have pigments to thank for vibrant flowers in the summer, leaves changing in the fall, and even the colors in our clothes!
Other butterflies use something called structural color. Their wings don’t have any inherent color, but look colorful to our eyes when light hits them. This takes advantage of the same scattering properties of light that create rainbows in the sky. These butterflies’ wings have structures that are so tiny that most microscopes can’t see them, and when light hits these structures, we see color because some colors are reflected and some are not. This idea is similar to the way that pigments work, but the difference is that the colors are determined by the shape of the structures instead of chemical properties. A lot of butterflies with very intense or iridescent colors use structural color, for example, the brilliant blue of Morpho butterflies is caused by these tiny structures in their wings!
If you want to learn more about butterflies or see any of these butterflies for yourself, you should check out your local butterfly garden. Here in Philadelphia, we have the Philadelphia Insectarium and Butterfly Pavilion which is full of beautiful butterflies from all over the world! While you’re there, you can try to guess what the different color patterns in butterflies’ wings are for and where those colors come from!