Glasswing Butterflies – Practically Invisible

We often overlook how hard it is to maintain the balance between different kinds of life in the natural world. For example, if an animal is too successful at avoiding predators and reproducing, it will eat up all of its available food. If it is not successful enough, it will become extinct because predators will wipe it out. Then the predators will be short of food. The design of life which allows animals and plants to exist in balance with their environment is amazing.

One design factor that protects many animals is camouflage. An excellent example of that is an insect known as glasswing butterflies (Greta oto) which have transparent wings. One scientist said that “transparency is the ultimate form of camouflage” because the insect can blend into any background, but transparency is “really hard to do.” Glasswings live in the rainforests of Central and South America.

Most living things are visible because they reflect light. However, microscopic studies of glasswing butterflies show that the wing material has low absorption, low reflection, and low scattering of light. Microscopic nanopillars on the wing’s surface are designed to minimize light reflection and smooth the refraction index gradient between the wing surface and the air. The result is a practically invisible wing except for the dark brown borders tinted with red or orange.

If you believe that natural selection is the sole cause of this design, why don’t all butterflies have transparent wings? This feature obviously favors the survival of the butterfly. Most butterflies have colorful, eye-catching wing patterns that make them visible while giving us an appreciation for the role of beauty in the creation.

From an evolutionary standpoint, there should be no butterflies left with colorful wings, but glasswing butterflies are the exception, not the rule. God has designed creatures to survive in all kinds of environments.

— John N. Clayton © 2021

Reference: Science News, July 31, 2021, page 32.