Donna Scarbrough, age 11, of Georgetown, Tex., for her question:

What does the daddy longlegs insect eat?

The daddy longlegs was named, of course, for his long long thin legs. It is not a scientific name, and we non experts tend to bestow it upon several bug type creatures with six or more extra long legs. If the fellow we call daddy longlegs has more than six legs, he is not a true insect.

As a rule, the bug we call a daddy longlegs is a fly. He is classified with a host of other two wing insects in the order diptera. If he is an insect, chances are he is a crane fly. But non experts often call the long legged harvestman a daddy longlegs and this fellow is a relative of the spiders. He is not a true insect; therefore, his diet has no place in the answer to this question.

There are thousands of assorted crane flies around the world, and if we search long enough we can find more than 500 different species in north america. They range in size from midget mosquitoes to whoppers with wing spreads of three inches. The biggest of the crane flies may be called a granddaddy longlegs. All of these insects are named crane flies because, like the crane birds, their legs seem to be extra long for their bodies.

Among so many crane flies we would expect to find different habits and diets. This is true. But all crane flies share features with all the other flies. They develop in four stages from eggs to larvae, from larvae to pupae and finally into two wing adults. They have large eyes, short antennae and mouths for sucking their food in liquid form.

Some of the flies sip liquids from fresh or decaying meat. The members of the crane fly family are strict vegetarians, and many of them eat only during the larvae or caterpillar stage of their life cyeles. This means that the adult bug we call daddy longlegs may eat nothing at all.

This, however, is not true of the larvae. These tough skinned little grubs live in the ground and devour scads of rooty vegetation. Plants need healthy roots to take in nourishment, and the grubs of the daddy longlegs destroy plant life by weakening the root systems. One variety is the farmer's hated pest called the leather jacket. This greedy burrower sips the juices from the roots of grains and grasses and does immense damage to our lawns and cereal crops.

Mrs. Crane fly lays her batch of hundreds of small eggs in the moist ground. The eggs become shiny brown larvae and begin a career of feasting that lasts several weeks. Then they don crusty brown coats and become pupae. This quiet chrysalis stage lasts perhaps a week. During this time, sealed safely in their crusty coats, the insects go through a metamorphosis, a thorough alteration that changes them from wormy grubs into winged insects ready to cope with life in the air.