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Was It Designed?

The Eye of the Moth

● Most moths fly chiefly at night. Whereas some nighttime creatures reveal their presence when a beam of light causes their eyes to glow, the moth has a stealth feature of sorts—its cornea is considerably less reflective.

Consider: The moth’s eye has an unusual cornea—it is composed of arrays of microscopic bumps, arranged in hexagonal patterns. The bumps “are smaller than the wavelength of visible light,” states Peng Jiang, an assistant professor of chemical engineering at the University of Florida, U.S.A. The pattern and size of those arrays enable a moth’s eye to trap light from several wavelengths and angles. The tiny bumps are only 200 to 300 nanometers in height. By way of comparison, the width of an average human hair is about 80,000 nanometers!

Engineers hope that a deeper understanding of the moth’s cornea will help them improve their design of light-emitting diodes (LEDs) and liquid crystal displays (LCDs), commonly used in electronic devices. The design of the moth’s eye might also be applied to solar power. Silicon solar panels may reflect as much as 35 percent of light—a significant waste of potential energy. However, by imitating the orderly bumps of the moth’s eye, Jiang and his collaborators fabricated a silicon that reflected less than 3 percent of light. “We can learn a great deal from these natural structures,” Jiang concludes.

What do you think? Did the tiny antireflective structure of the moth’s eye come about by chance? Or was it designed?

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The moth’s eye has a cornea composed of arrays of microscopic bumps arranged in hexagonal patterns

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A silicon wafer with an antireflection array used for solar panels

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Moth eye close-up: Courtesy of Dartmouth Electron Microscope Facility; silicon close-up: Courtesy Peng Jiang