The Hercules beetle lives in the rain forests
of Central and South America. The beetle is also found along the coast of North Carolina. It is a type of rhinoceros beetle
with long horns on the males. Including horns, the beetles reach a length of six to eight inches. They may appear threatening
but actually are harmless and are sometimes kept as pets. The Hercules name derives from their impressive strength. Experiments
show that their strong backs can support and carry a load equal to 850 times their weight. The equivalent load for a 200 pound
person would be 170,000 pounds, equal to 3-4 loaded cement trucks!
A hard shell material covers the back of
the Hercules beetle. Researchers in Belgium study how this surface is able to change color. It is normally bright green, but
turns black when wet. It appears that tiny water droplets interfere with the refraction and reflection of light colors. As
this mechanism is better understood and duplicated, scientists hope to make small humidity detectors, or hygrometers, in the
form of adhesive tape. Such devices could be applied to many products. On flowerpots, a color change would indicate the need
for water. Classroom blackboards could use a water-filled ‘moisture pen’ instead of chalk, and be erased with
a pulse of heat. Moisture-sensitive car finishes could change color in the rain, making them more visible.