The large wings of butterflies are covered with tiny, colorful scales. The effect of all these tiny scales combined is what gives butterflies the beautiful and sometimes complex patterns on their wings. Besides moths, there is no other insect group that has these types of scales on their wings. The colors serve primarily to provide protection through camouflage or to attract potential mates.
Butterflies got their colors as part of an evolutionary process. Both moths and butterflies belong to the scaled wing order of insects known as Lepidoptera. Moths came before butterflies, and their fossilized remains date to 150 million years ago. Millions of years ago some moths, which are usually nocturnal, became active during the day and had scales with brighter colors. These traits gave certain advantages, leading to the bright colors of butterflies.
When a brightly colored butterfly does not want to stand out, like on an overcast day, it closes its wings and hide its colors. With wings closed, butterflies become difficult to see. Other butterflies have colors that allow them to blend in with their surroundings. This is known as cryptic coloration, and it fools predators. The butterflies’ colors blend in so well with the environment that the insect is almost indistinguishable.
Warning and Signaling
Many groups of butterflies have bright colors that warn predators that they are poisonous and don’t taste good. The monarch butterfly, with its black and orange markings, is a good example. Birds have learned to avoid them, associating the colors with danger. The caterpillar of the monarch butterfly eats the leaves of the milkweed tree, making the butterfly both toxic and bitter for birds. For some butterflies, the colors and markings on their wings mean something else entirely. They are a way to identify and attract potential mates.
Some butterflies have colors on their wings that warn predators that they are poisonous and not very tasty. But these sneaky butterflies are not poisonous, and they could make a fine meal for a hungry bird. The butterflies have colors that mimic or copy the markings on poisonous butterflies. Over time, predators learned to avoid both butterflies. An example is the viceroy butterfly, which mimics the monarch butterfly’s orange and black markings.