Cicada
|
|
| Cicada | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
 | ||||||||||||
| Scientific classification | ||||||||||||
| ||||||||||||
| Genera | ||||||||||||
|
Many. |
A cicada is any of several insects of the order Hemiptera, suborder Homoptera, with small eyes wide apart on the head and transparent well-veined wings. Cicadas live in temperate to tropical climates.
| Contents |
Taxonomy
There are many species of cicadas—the numbers vary, but there are many thousands. The largest cicadas are in the genera Pomponia and Tacua. There are some 200 species in 38 genera in Australia, about 100 in the Palaearctic and exactly one species in England, the New Forest Cicada (Melampsalta montana), which is widely distributed throughout Europe, where about 2,000 species are known (some 600 in Germany alone).
Most of the North American species are in the genus Tibicen—the annual or dog-day cicadas (named after the "Dog Days" because they emerge in late July and August). The best-known North-American genus is Magicicada, however. These periodical cicadas have an extremely long life cycle of 13 or 17 years and emerge in large numbers. Another American species is the Apache Cicada (Diceroprocta apache).
38 species from 5 genera populate New Zealand, and all of the species are endemic to New Zealand and the surrounding islands (Norfolk Island, New Caledonia).
Description
Imagines of cicadas are usually between 2 and 5 cm (1 to 2 inches) long, although there some tropic species that reach 15 cm (6 in), e.g. the Pomponia imperatoria from Malaysia. Cicadas have prominent eyes set wide apart on the sides of the head, short antennae protruding between or in front of the eyes, and membranous front wings.
Male cicadas have loud noisemakers called "tymbals" on their sides. Their "singing" is actually a kind of stridulation: they vibrate these membranes with strong muscles; their body serves as a resonance body greatly amplifying the sound. Some cicadas produce sounds louder than 100 dB. (This amazing sound has frequently inspired haiku poets in Japan to write about them.) They modulate their noise by wiggling their abdomens toward and away from the tree that they are on.
Life cycle
Most cicadas go through a life cycle that lasts between two to five years. Some species have much longer life cycles, e.g. the Magicicada goes through a 13- or even 17-year life cycle.
Most of this time, the animals spend underground as nymphs at depths ranging from about 30 cm (1 ft) up to 2.5 m (about 8½ ft). The nymphs feed on root juices and have strong front legs for digging.
In the final nymphal instar, they construct an exit tunnel to the surface and emerge. On a nearby plant, they molt one last time and emerge as an adult.
Only the males have tymbals and "sing" to attract females. After mating, the female cuts slits into the bark of a twig and deposits her eggs there. She may do so repeatedly, until she has laid several hundred eggs. When the eggs hatch, the newborn nymphs drop to the ground, where they burrow and start another cycle.
See also
- Cicada Killer Wasp, a predator of cicadas.
- Magicicada, the periodical cicada, or "seventeen-year locust".
External links
- Cicada and forest mulch (http://news.bbc.co.uk/2/hi/science/nature/4046557.stm)
- Cicadas pictures (http://www.cicadas-pictures.com) shares facts and pictures regarding cicadas and their behavior, life cycle, and feeding habits.
- Cicada Mania (http://www.cicadamania.net) cicada news, FAQs, links, pictures and video.eo:Cikado