Jerry Cooper, age 10, of Winston Salem, N.C., for his question:
WHY DO MOTHS STAY AROUND LIGHTS?
Some people suspect that a moth flies into a candle flame in order to commit suicide. This, of course, is downright nonsense, for even nature's dumb little lemmings do not kill themselves on purpose. As a matter of fact, all nature's children are much too brave to end their lives on purpose, even when their problems get too tough to handle.
Summer is the season when swarms of assorted insects arrive from who knows where. In the warm evenings outdoors we watch in amazement as moths gather around our patio lights. Meantime squadrons of mayflies and June bugs are busy bashing into the street lamps.
A moth spirals around a candle, somewhat as you ride a curved path when you turn your bicycle handlebars to the right or left. The insect's path involves angles and eyesight anddates back hundreds of millions of years. No doubt you have wondered how a busy bee knows to make a beeline straight home.
Most insects use the same system of angles to find their way there and back. This is because they adjust their paths to the angles of light rays such as sunbeams, starlight and moonbeams. For example, suppose these beams from afar strike the eyes at an angle of 80 degrees. An insect flies a straight course if he keeps adjusted to the same angle.
Rays of light, as we know, fan out from the center. As they go, their lines and angles spread wider and wider. However, by the time they reach the earth, the rays from a heavenly body are almost parallel. So for countless ages the insects were able to depend on these angles to fly in straight paths.
Then the human family arrived and invented on the¬spot lights to brighten the dark night. Rays from a nearby candle fan out in widening angles. This is what lures a night flying insect to his doom. Suppose the rays from a nearby lamp strike a moth's eyes at 80 degrees. If he tries to keep this angle across the spreading rays, his path will curve inward, closer and closer to the light.
True, this system of angles and eyesight is very complex and quite hard to understand. But in a simplified way, somewhat the same thing happens when you ride your bike. To ride a straight path, you keep the handlebars straight, as a moth flies by starlight. When you turn the handlebars to the left or right, you ride around in a curve. When the moth flies by the light of a nearby lamp, he curves around and spirals into the center.