Was It Designed?

The Cold Light of the Firefly

● In tropical and temperate regions, the firefly is recognized by the flashing light it uses to attract a mate. Interestingly, the firefly’s light is superior to the incandescent and fluorescent light produced by man. In fact, the next time you look at your electric bill, think of what this small insect can do.

Consider: An incandescent lightbulb emits only 10 percent of its energy as light; the rest is basically wasted, discharged as heat. A fluorescent bulb performs much better, emitting 90 percent of its energy as light. But neither of these is a match for the firefly. With very few ultraviolet or infrared rays, the light emitted by this insect is nearly 100 percent energy efficient!

The firefly’s secret lies in the chemical reactions of the substance luciferin, the enzyme luciferase, and oxygen. Special cells called photocytes use luciferase to trigger this process, with oxygen as fuel. The result is cold light​—so named because it produces virtually no heat. Horticultural and environmental educator Sandra Mason aptly remarked that lightbulb inventor Thomas Edison “must have been envious of fireflies.”

What do you think? Did the cold light of the firefly come about by chance? Or was it designed?

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LIGHT EFFICIENCY

Incandescent bulb 10%

Fluorescent bulb 90%

Firefly 96%

[Picture Credit Lines on page 15]

Firefly on leaf: © E. R. Degginger/​Photo Researchers, Inc.; firefly in flight: © Darwin Dale/​Photo Researchers, Inc.