Tuesday, June 29, 2004

Cicada -- the 17yr insect @!!!

Been reading abt the mighty Cicada X worm;;

Cicada Facts:

The cicada is related to the harvest fly.Some cicada's live underground for seventeen years.The cicada grows up to three inches.Cicadas suck juice from tree roots when they are larva.Once the female cicada comes above ground, she mates. Then she lays her eggs and dies.The cicada can lay four hundred to six hundred eggs.
The adult cicada lives in trees.Adult cicadas live for thirty to forty days.
A cicada can chirp so loud you can hear it from half a mile away.A male cicada abdomen has two drum like sound chambers.
There are two main kinds of periodical cicadas in the United States. One kind spends 17 years as a nymph feeding on tree roots while living below ground, and the other lives underground for 13 years! Then each type, as if on some signal, emerges at the same time from the ground. They change into adults, lay eggs, and after a few weeks, they die. We don't see the next generation until 13 or 17 years later!
Voted least likely to need a megaphone... The male cicada makes the loudest sound in the insect world. By vibrating the ribbed plates in a pair of amplifying cavities at the base of the abdomen, the mating sound of the cicada can be heard as far as 440 yards! These insect noisemakers rarely ever stop calling for a mate. The noise from large groups of cicadas can often drown out even the noisiest lawnmower.

The 13-year and 17-year cicadas, known as periodical cicadas, are both large-bodied insects with orange-veined wings.The periodical varieties look, sound and behave alike. The only characteristic making them different from one another is the length of time they spend in the ground during the nymphal stages--either 13 or 17 years.

Periodical cicada adults are spectacular in appearance. The body is mostly black on top. The head is broad, and the abdomen tapers to the rear. Eyes are very red. Their legs and wing veins are reddish orange, and their wings are nearly transparent with an orange tint. Despite their fearsome appearance, with bulging, bright red eyes, cicadas are harmless to animal life and all trees except young saplings.

It is easy to tell the gender of cicada adults. Females have blade-like ovipositors visible on the bottom surface of the abdomen, and the males do not. Males possess a pair of sound-producing, or "singing", organs located on the sides of the first abdominal segment. Each sound organ consists of a large plate-like structure, the operculum, which covers a cavity containing a white or yellowish membrane and an oval, ribbed, drum-like structure called a timbal. Timbals are vibrated by strong muscles to produce the cicada song.

After cicada eggs hatch, the tiny, antlike nymphs quickly drop from the trees and burrow five to 46 centimeters (two to 18 inches) underground in search of tree roots to feed upon. For the next 13 to 17 years they feed on the juicy roots of plants. After 13 or 17 years, a natural "clock," which remains a mystery to scientists, tells them that it is time to come out of the ground. In the weeks before the nymphs emerge, periodical cicadas dig their tunnels to the soil surface and prepare to leave the ground. Amazingly all the cicadas seem to come out of the ground at the same time in enormous numbers. The nymphs leave the ground and begin to climb trees and poles. As they climb, they molt, or grow out of their exoskeleton. They split open the back of their brown and brittle exoskeletons, wiggle out, and abandon them, empty and still clinging to the trees. They continue to climb to the treetops to begin their constant buzzing calls, trying to attract a mate. If they are successful, mating occurs, eggs are laid and the cycle begins again.
After mating, adult female cicadas use their blade like ovipositor to make long openings in new growth sections of tree branches. A female usually lays 20 to 30 eggs in each opening, and there can be several egg "nests" per branch. During her short adult life stage, each female lays approximately 600 eggs. The eggs take six to eight weeks to mature--after which the nymphs drop to the ground and immediately begin their descent into an underground world. Their long nymphal stage is unmatched within the animal kingdom and continues to draw the interest of scientists.

further links;Cicada at wikipedia -- http://en.wikipedia.org/wiki/Cicada

The University of Michigan Museum of Zoology --

http://eny3005.ifas.ufl.edu/lab1/ -- University of Florida Entomology Dept.


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