Carl Haefner III, age 10, of Williamsport, Pa., for his question:
Where do fireflies spend the winter?
Fireflies belong to warm summer evenings, or so it seems. It would be nice if they were around in the winter to add their twinkling sparks to the falling snowflakes. But they are not and this is quite mysterious. For if they all died out in the fall there would be no fireflies next summer. Obviously they must have safe and secret hiding places to spend the winter. But where in the world are they?
Dozens of different fireflies flash their fairy lights in different parts of the world. But they're not really flies. Actually they are beetles and it so happens that the beetle insects outnumber all the other creatures in the world. All of them live their lives in four separate stages, and in most cases their life stages are timed to match the summer and winter seasons.
The life cycle begins on a warm summer evening when those soft golden sparks wink on and wink off. The male fireflies are winking and blinking signals to the females. Soon the females reply with winks. of their own, and the couples find each other.
After the mating, a female firefly lays at least 75 little round eggs and maybe as many as 150. Chances are she lays them on the ground in fallen leaves or rotting wood. After a week or 10 days, the eggs hatch and the baby larvae are close to their favorite food. This is very important because, during a beetle's lifetime, most of his eating is done during the larval stage.
Many kinds of firefly larvae are meat eaters. They have special digestive juices to dissolve the bodies of snails and slugs. Other types prefer plant food and feed on roots or rotting wood. In any case, the female lays her eggs where the wormy grubs will find plenty of their favorite foods.
'Since many fireflies live in tropical and semitropical cimates, they do not have to worry too much about the winter. Some types spend the entire winter in the larval stage. Others live as larvae through several years summers and winters. But sooner or later each grubby worm must progress to the next stage of his life.
When he has eaten all he possibly can, which may be enough to last through the rest of his life, the firefly larva burrows down into the ground and becomes a pupa. If the winter season is chilly, he may remain in this stage until spring. When the warm weather returns, the pupa cracks open and an adult winged firefly struggles forth to add his winking sparkles to the evening air.
The adult fireflies live only long enough to mate and lay their eggs. Usually they eat little or nothing at all. Before the fragile creatures depart, they leave eggs for the next generation. In cool climates, the hungry larvae feast for three months or so and survive the winter as tough little pupas buried in the ground. In warmer climates, the larvae often go on feasting through several years.