Richard Robinson, age 12, of Bird in Hand, Pennsylvania, for his question:

What is the life span of a common housefly?

The average housefly may live through the warm season of one year, maybe six months or a little more. This can occur, however, only if she happens to be born very early in the spring. Dozens of batches of eggs appear throughout the entire season. Her chances of hatching from a later batch are more likely. In this case, her life expectancy is shorter. Almost always she perishes in the fall before the winter weather arrives.

True, the life expectancy of a housefly is merely a few months. But the busy bug manages to accomplish a staggering amount of multiplication during this time. Let's say she hatches in April. In a week or so she lays 500 eggs of her own. In another week her offspring could produce 125,000 eggs. At this rate, she could produce some 200 million million million descendants between April and August. Fortunately this population explosion does not take over the world. Most of the teeming horde becomes food for countless creatures. In the fall, the adults depart, leaving, the last batches of eggs to sleep through the winter. No doubt by this time, that first little mother is totally exhausted features.