Denita Turpin, age 12, of Newport News, Virginia, for her question:
What exactly are cicadas?
Cicadas are true earthlings, but when they arrive you might suspect that swarms of aliens have landed from a U.F.O. For the cicadas have big bulging bug eyes, whirring wings and many of them are tinged with green. They create a vibrating noise that is heard far and wide. No they are not aliens. Cicadas are certain insects that appear for a few days, then disappear for three, ten or perhaps 17 years.
In the summer of 1972, many people in Southern and Central states reported plagues of locusts which are wretched insects that arrive in swarms and devour every green leaf in sight. In Colonial days, entire crops were stripped bare by these plagues, but nowadays these famished locusts are rather rare. Those swarms of insects that arrived in 1972 were cicadas.
Actually, there was nothing to fear because these big buzzing insects do not eat during their brief visits. They are interested only in mating and depositing eggs for the next cicada appearance. This may be after a year, after three or ten years and one species will not be heard from again for 17 years.
The true locusts are members of the grasshopper clan. They have one pair of extra long strong legs for leaping and two pairs of large wings. The two leathery front wings cover a pair of gauzy flying wings that open like fans. These insects are not related to the cicadas, who belong in the family Cicadidae.
A cicada is about the size of a grasshopper and he has the same sort of a bullet shaped head with big round eyes. But he does not have that extra large pair of leaping legs and his two pairs of large dainty wings are crisp, transparent gauze that catches glints of rainbow colors from the sunbeams.
The female cicada deposits her eggs, one at a time, in the wrinkled bark of a tree trunk. When they hatch, the tiny wingless youngsters drop to the ground and burrow below. These immature larvae are called nymphs and they will molt several times before they emerge as winged adult cicadas.
Meantime they live underground, feeding on sap from the roots of plants. Now comes the strange part. There are several cicada species and their nymph stage varies from one to 17 years. All that time they stay below and emerge only to spend a few exciting days as adults. After the brief mating season they die and the ground is strewn with their dainty bodies. .
Patient scientists have traced the life histories of the common cicadas and they can predict when and where the most numerous broods are likely to appear. For example, next summer broods of the 17 year cicadas are expected to appear in the Carolinas and Kentucky, also in parts of the midwestern and northern states. Just remember, they are not greedy locusts.