Cicada
The cicadas are a superfamily, the Cicadoidea, of insects in the order Hemiptera. They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two families, the Tettigarctidae, with two species in Australia, and the Cicadidae, with more than 3,000 species described from around the world; many species remain undescribed. Nearly all cicada species are annual cicadas with the exception of the few North American periodical cicada species, genus Magicicada, which in a given region emerge en masse every 13 or 17 years.
Cicadas have prominent eyes set wide apart, short antennae, and membranous front wings. They have an exceptionally loud song, produced in most species by the rapid buckling and unbuckling of drum-like tymbals. The earliest known fossil Cicadomorpha appeared in the Upper Permian period; extant species occur all around the world in temperate to tropical climates. They typically live in trees, feeding on watery sap from xylem tissue, and laying their eggs in a slit in the bark. Most cicadas are cryptic. The vast majority of species are active during the day as adults, with some calling at dawn or dusk. Only a rare few species are known to be nocturnal.
One exclusively North American genus, Magicicada, which spend most of their lives as underground nymphs, emerge in predictable intervals of 13 or 17 years, depending on the species and the location. The unusual timing and synchronization of their emergence may reduce cicada losses to predation by making them less reliable prey and by overwhelming predators with sheer numbers before significant losses occur.
The annual cicadas are species that emerge every year. Though these cicadas' life cycles can vary from one to nine or more years as underground nymphs, their emergence above ground as adults is not synchronized, so some members of each species appear every year.
Cicadas have been featured in literature since the time of Homer's Iliad and as motifs in art from the Chinese Shang dynasty. They have also been used in myth and folklore as symbols of carefree living and immortality. The cicada is also mentioned in Hesiod's Shield, in which it is said to sing when millet first ripens. Cicadas are eaten by humans in various parts of the world, including China, Myanmar, Malaysia, central Africa and parts of Mexico.
Etymology
The name is directly from the onomatopoeic Latin cicada.Taxonomy and diversity
The superfamily Cicadoidea is a sister of the Cercopoidea. Cicadas are arranged into two families: the Tettigarctidae and Cicadidae. The two extant species of the Tettigarctidae include one in southern Australia and the other in Tasmania. The family Cicadidae is subdivided into the subfamilies Cicadettinae, Cicadinae, Derotettiginae, Tibicininae, and Tettigomyiinae, and they are found on all continents except Antarctica. Some previous works also included a family-level taxon called the Tibiceninae. The largest species is the Malaysian emperor cicada Megapomponia imperatoria; its wingspan is up to about. Cicadas are also notable for the great length of time some species take to mature.At least 3,000 cicada species are distributed worldwide, in essentially any habitat that has deciduous trees, with the majority being in the tropics. Most genera are restricted to a single biogeographical region, and many species have a very limited range. This high degree of endemism has been used to study the biogeography of complex island groups such as in Indonesia and Asia. There are several hundred described species in Australia and New Zealand, around 150 in South Africa, over 170 in America north of Mexico, at least 800 in Latin America, and over 200 in Southeast Asia and the Western Pacific.
About 100 species occur in the Palaearctic. A few species are found in southern Europe, and a single species was known from England, the New Forest cicada, Cicadetta montana, which also occurs in continental Europe. Many species await formal description and many well-known species are yet to be studied carefully using modern acoustic analysis tools that allow their songs to be characterized.
Many of the North American species are the annual or jarfly or dog-day cicadas, members of the Neotibicen, Megatibicen, or Hadoa genera, so named because they emerge in late July and August. The best-known North American genus, however, may be Magicicada. These periodical cicadas have an extremely long life cycle of 13 or 17 years, with adults suddenly and briefly emerging in large numbers.
Australian cicadas are found on tropical islands and cold coastal beaches around Tasmania, in tropical wetlands, high and low deserts, alpine areas of New South Wales and Victoria, large cities including Sydney, Melbourne, and Brisbane, and Tasmanian highlands and snowfields. Many of them have common names such as cherry nose, brown baker, red eye, greengrocer, yellow Monday, whisky drinker, double drummer, and black prince. The Australian greengrocer, Cyclochila australasiae, is among the loudest insects in the world.
More than 40 species from five genera populate New Zealand, ranging from sea level to mountain tops, and all are endemic to New Zealand and its surrounding islands. One species is found on Norfolk Island, which technically is part of Australia. The closest relatives of the NZ cicadas live in New Caledonia and Australia.
File:Mesogereon superbum 2.jpg|thumb|Mesozoic fossil fore wing of Mesogereon superbum, Australia
Palaeontology
Fossil Cicadomorpha first appeared in the Late Triassic. The superfamily Palaeontinoidea contains three families. The Upper Permian Dunstaniidae are found in Australia and South Africa, and also in younger rocks from China. The Upper Triassic Mesogereonidae are found in Australia and South Africa. This group, though, is currently thought to be more distantly related to Cicadomorpha than previously thought.File:Prolystra lithographica.JPG|thumb|The giant cicada Prolystra lithographica from Germany, Jurassic, about 145–150 million years ago
The Palaeontinidae or "giant cicadas" come from the Jurassic and Lower Cretaceous of Eurasia and South America. The first of these was a fore wing discovered in the Taynton Limestone Formation of Oxfordshire, England; it was initially described as a butterfly in 1873, before being recognised as a cicada-like form and renamed Palaeontina oolitica.
Tettigarctidae and Cicadidae had diverged from each other prior to or during the Jurassic, as evidenced by fossils related to both lineages present by the Middle Jurassic. The morphology of well preserved fossils of early relatives of Cicadidae from the mid Cretaceous Burmese amber of Myanmar suggests that unlike many modern cicadids, they were either silent or only made quiet sounds. Most fossil Cicadidae are known from the Cenozoic, and the oldest unambiguously identified modern cicadid is Davispia bearcreekensis from the Paleocene, around 56–59 million years ago.
Biology
Description
Cicadas are large insects made conspicuous by the courtship calls of the males. They are characterized by having three joints in their tarsi, and having small antennae with conical bases and three to six segments, including a seta at the tip. The Auchenorrhyncha differ from other hemipterans by having a rostrum that arises from the posteroventral part of the head, complex sound-producing membranes, and a mechanism for linking the wings that involves a down-rolled edging on the rear of the fore wing and an upwardly protruding flap on the hind wing.Cicadas are feeble jumpers, and nymphs lack the ability to jump altogether. Another defining characteristic is the adaptations of the fore limbs of nymphs for underground life. The relict family Tettigarctidae differs from the Cicadidae in having the prothorax extending as far as the scutellum, and by lacking the tympanal apparatus.
The adult insect, known as an imago, is in total length in most species. The largest, the empress cicada, has a head-body length around, and its wingspan is. Cicadas have prominent compound eyes set wide apart on the sides of the head. The short antennae protrude between the eyes or in front of them. They also have three small ocelli located on the top of the head in a triangle between the two large eyes; this distinguishes cicadas from other members of the Hemiptera. The mouthparts form a long, sharp rostrum that they insert into the plant to feed. The postclypeus is a large, nose-like structure that lies between the eyes and makes up most of the front of the head; it contains the pumping musculature.
The thorax has three segments and houses the powerful wing muscles. They have two pairs of membranous wings that may be hyaline, cloudy, or pigmented. The wing venation varies between species and may help in identification. The middle thoracic segment has an operculum on the underside, which may extend posteriorly and obscure parts of the abdomen. The abdomen is segmented, with the hindermost segments housing the reproductive organs, and terminates in females with a large, saw-edged ovipositor. In males, the abdomen is largely hollow and used as a resonating chamber.
The surface of the fore wing is superhydrophobic; it is covered with minute, waxy cones, blunt spikes that create a water-repellent film. Rain rolls across the surface, removing dirt in the process. In the absence of rain, dew condenses on the wings. When the droplets coalesce, the cicada leaps several millimetres into the air, which also serves to clean the wings. Bacteria landing on the wing surface are not repelled; rather, their membranes are torn apart by the nanoscale-sized spikes, making the wing surface the first-known biomaterial that can kill bacteria.