EtymologyThe name is directly from the ''cicada''.
Taxonomy and diversityThe superfamily Cicadoidea is a sister of the (the froghoppers). Cicadas are arranged into two families: the Tettigarctidae and Cicadidae. The two species of the Tettigarctidae include one in southern Australia and the other in . The family Cicadidae is subdivided into the subfamilies , , , (or Tettigadinae), and they are found on all continents except Antarctica. Some previous works also included a family-level taxon called the . The largest species is the Malaysian emperor cicada '; its wingspan is up to about . Cicadas are also notable for the great length of time some species take to mature. At least 3000 cicada species are distributed worldwide, 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 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 , 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 . A few species are found in southern Europe, and a single species was known from England, the , ''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 cicadas, members of the '', '', or '' ''genera, so named because they emerge in late July and August. The best-known North American genus, however, may be '. These periodical cicadas have an extremely long life cycle of 13 or 17 years, with adults suddenly and briefly . are found on tropical islands and cold coastal beaches around Tasmania, in tropical wetlands, high and low deserts, alpine areas of and , large cities including , , and , and Tasmanian highlands and snowfields. Many of them have common names such as cherry nose, brown baker, , greengrocer, yellow Monday, whisky drinker, , and black prince. The Australian greengrocer, ', 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 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.
PalaeontologyFossil Cicadomorpha first appeared in the . The superfamily contains three families. The Upper Permian Dunstaniidae are found in Australia and South Africa, and also in younger rocks from China. The Mesogereonidae are found in Australia and South Africa. This group, though, is currently thought to be more distantly related to Cicadomorpha than previously thought. The or "giant cicadas" come from the and of Eurasia and South America. The first of these was a fore wing discovered in the of Oxfordshire, England; it was initially described as a butterfly in 1873, before being recognised as a cicada-like form and renamed '. Most fossil Cicadidae are known from the Cenozoic, and the oldest unambiguously identified specimen is ''Davispia bearcreekensis'' (subfamily Tibicininae) from 59–56 million years ago (Mya). One fossil genus and species (''Burmacicada protera'') based on a first-instar nymph has recently been reported from 98–99 Mya in the Late Cretaceous, although questions remain about its assignment to the Cicadidae.
DescriptionCicadas are large insects made conspicuous by the courtship calls of the males. They are characterized by having three joints in their , and having small with conical bases and three to six segments, including a at the tip. The differ from other hemipterans by having a 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 extending as far as the , and by lacking the tympanal apparatus. The adult insect, known as an , is in total length in most species. The largest, the (''Megapomponia imperatoria''), 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 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 that they insert into the plant to feed. The 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 , cloudy, or pigmented. The wing venation varies between species and may help in identification. The middle thoracic segment has an 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 . In males, the abdomen is largely hollow and used as a resonating chamber. The surface of the fore wing is ; 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, condenses on the wings. When the droplets coalesce, they leap several millimetres into the air, which also serves to clean the wings. 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 that can kill bacteria.
Temperature regulationDesert cicadas such as ' are unusual among insects in controlling their temperature by , analogous to in mammals. When their temperature rises above about 39°C, they suck excess sap from the food plants and extrude the excess water through pores in the at a modest cost in energy. Such a rapid loss of water can be sustained only by feeding on water-rich . At lower temperatures, feeding cicadas would normally need to excrete the excess water. By evaporative cooling, desert cicadas can reduce their bodily temperature by some 5°C. Some non-desert cicada species such as ''Magicicada tredecem'' also cool themselves evaporatively, but less dramatically. Conversely, many other cicadas can voluntarily raise their body temperatures as much as above ambient temperature.
SongThe "singing" of male cicadas is produced principally and in the majority of species using a special structure called a , a pair of which lies below each side of the region. The structure is buckled by muscular action and, being made of , unbuckles rapidly on muscle relaxation, producing their characteristic sounds. Some cicadas, however, have mechanisms for , sometimes in addition to the tymbals. Here, the wings are rubbed over a series of midthoracic ridges. In the Chinese species ', both males and females can stridulate. The sounds may further be modulated by membranous coverings and by resonant cavities. The male abdomen in some species is largely hollow, and acts as a . By rapidly vibrating these membranes, a cicada combines the clicks into apparently continuous notes, and enlarged chambers derived from the serve as s with which it amplifies the sound. The cicada also modulates the song by positioning its abdomen toward or away from the substrate. Partly by the pattern in which it combines the clicks, each species produces its own distinctive mating songs and acoustic signals, ensuring that the song attracts only appropriate mates. The tettigarctid (or hairy) cicadas ' of Australia and ''T. tomentosa'' have rudimentary tymbals in both sexes and do not produce airborne sounds. Both males and females produce vibrations that are transmitted through the tree substrate. They are considered as representing the original state from which other cicada communication has evolved. Average temperature of the natural habitat for the South American species ''Fidicina rana'' is about . During sound production, the temperature of the tymbal muscles was found to be significantly higher. Many cicadas sing most actively during the hottest hours of a summer day; roughly a . Most cicadas are diurnal in their calling and depend on external heat to warm them up, while a few are capable of raising their temperatures using muscle action and some species are known to call at dusk. ''Kanakia gigas'' and ''Froggattoides typicus'' are among the few that are known to be truly nocturnal and there may be other nocturnal species living in tropical forests. Cicadas call from varying heights on trees. Where multiple species occur, the species may use different heights and timing of calling. While the vast majority of cicadas call from above the ground, two Californian species, ''Okanagana pallidula'' and ''O. vanduzeei'' are known to call from hollows made at the base of the tree below the ground level. The adaptive significance is unclear, as the calls are not amplified or modified by the burrow structure, but this may avoid . Although only males produce the cicadas' distinctive sounds, both sexes have membranous structures called (singular – tympanum) by which they detect sounds, the equivalent of having ears. Males disable their own tympana while calling, thereby preventing damage to their hearing; a necessity partly because some cicadas produce sounds up to 120 which is among the loudest of all insect-produced sounds. The song is loud enough to cause permanent in humans should the cicada be at "close range". In contrast, some small species have songs so high in pitch that they are inaudible to humans. For the human ear, telling precisely where a cicada song originates is often difficult. The pitch is nearly constant, the sound is continuous to the human ear, and cicadas sing in scattered groups. In addition to the mating song, many species have a distinct distress call, usually a broken and erratic sound emitted by the insect when seized or panicked. Some species also have courtship songs, generally quieter, and produced after a female has been drawn to the calling song. Males also produce encounter calls, whether in courtship or to maintain personal space within choruses. The songs of cicadas are considered by entomologists to be unique to a given species, and a number of resources exist to collect and analyse cicada sounds.
Life cycleIn some species of cicadas, the males remain in one location and call to attract females. Sometimes, several males aggregate and call in chorus. In other species, the males move from place to place, usually with quieter calls, while searching for females. The Tettigarctidae differ from other cicadas in producing vibrations in the rather than audible sounds. After mating, the female cuts slits into the bark of a twig where she deposits her eggs. Both male and female cicadas die within a few weeks after emerging from the soil. Although they have mouthparts and are able to consume some plant liquids for nutrition, the amount eaten is very small and the insects have a natural adult lifespan of less than two months. When the eggs hatch, the newly hatched drop to the ground and burrow. Cicadas live underground as nymphs for most of their lives at depths down to about . Nymphs have strong front legs for digging and excavating chambers in close proximity to roots, where they feed on sap. In the process, their bodies and interior of the burrow become coated in anal fluids. In wet habitats, larger species construct mud towers above ground to aerate their burrows. In the final nymphal , they construct an exit tunnel to the surface and emerge. They then (shed their skins) on a nearby plant for the last time, and emerge as adults. The or abandoned exoskeletons remain, still clinging to the bark of the tree. Most cicadas go through a life cycle that lasts 2–5 years. Some species have much longer life cycles, such as the North American genus, ''Magicicada'', which has a number of distinct "broods" that go through either a 17-year, or in some parts of the region, a 13-year life cycle. The long life cycles may have developed as a response to , such as the and . A specialist predator with a shorter life cycle of at least two years could not reliably prey upon the cicadas. An alternate hypothesis is that these long life cycles evolved during the ice ages so as to overcome cold spells, and that as species co-emerged and hybridized, they left distinct species that did not hybridize having periods matching prime numbers.
DietCicada nymphs drink sap from the xylem of various species of trees, including , , , , and . While common folklore indicates that adults do not eat, they actually do drink plant sap using their sucking mouthparts.
LocomotionCicadas, unlike other Auchenorrhyncha, are not adapted for jumping (saltation). They have the usual insect modes of , walking and flight, but they do not walk or run well, and take to the wing to travel distances greater than a few centimetres.
Predators, parasites, and pathogensCicadas are commonly eaten by birds and sometimes by squirrels, as well as s, s, es, s, and . In times of mass emergence of cicadas, various amphibians, fish, reptiles, mammals, and birds change their foraging habits so as to benefit from the glut. Newly hatched nymphs may be eaten by ants, and nymphs living underground are preyed on by burrowing mammals such as moles. In Australia, cicadas are preyed on by the Australian cicada killer wasp ('), which stings and stuns cicadas high in the trees, making them drop to the ground, where the cicada hunter mounts and carries them, pushing with its hind legs, sometimes over a distance of 100 m, until they can be shoved down into its burrow, where the numb cicadas are placed onto one of many shelves in a "catacomb", to form the food stock for the wasp grub that grows out of the egg deposited there. A predator from Australia is capable of attracting singing male cicadas of a variety of species by imitating the timed click replies of sexually receptive female cicadas, which respond in pair formation by flicking their wings. Several fungal diseases infect and kill adult cicadas, while other , ' spp., attack nymphs. ' specifically attacks the adults of periodical cicadas, the spores remaining dormant in the soil between outbreaks. This fungus is also capable of dosing cicadas with , the found in , as well as , an similar to various . These chemicals alter the behaviour of the cicadas, driving males to copulate, including attempts with males, and is thought to be beneficial to the fungus, as the fungal spores are dispersed by a larger number of infected carriers. Plants can also defend themselves against cicadas. Although cicadas can feed on the roots of gymnosperms, it has been found that resinous conifers such as pine do not allow the eggs of ''Magicicada'' to hatch, the resin sealing up the egg cavities.
Antipredator adaptationsCicadas use a variety of strategies to evade predators. Large cicadas can fly rapidly to escape if disturbed. Many are extremely well d to evade predators such as birds that hunt by sight. Being coloured like tree bark and to break up their outlines, they are difficult to discern; their partly transparent wings are held over the body and pressed close to the substrate. Some cicada species when threatened. Some cicadas such as ' display bright flash coloration on their hind wings when threatened; the sudden contrast helps to startle predators, giving the cicadas time to escape. Most cicadas are and rely on camouflage when at rest, but some species use -related , wearing the bright colors that warn of toxicity in other animals; the Malaysian ' has conspicuous red and black warning coloration, is diurnal, and boldly flies about in full view of possible predators. Predators such as the fly ' hunt cicadas by sound, being attracted to their songs. Singing males soften their song so that the attention of the listener gets distracted to neighbouring louder singers, or cease singing altogether as a predator approaches. A loud cicada song, especially in chorus, has been asserted to repel predators, but observations of predator responses refute the claim.
In human culture
In art and literatureCicadas have been featured in literature since the time of Homer's ''Iliad'', and as motifs in decorative art from the Chinese Shang dynasty (1766–1122 BCE). They are described by in his ' and by in his '; their mechanism of sound production is mentioned by in his poem "": "when the flowers, and the tuneful ''Tettix'' sitting on his tree in the weary summer season pours forth from under his wings his shrill song". In the classic 14th-century Chinese novel ', took her name from the sable (''diāo'') tails and jade decorations in the shape of cicadas (''chán''), which adorned the hats of high-level officials. In the Japanese novel ', the title character poetically likens one of his many love interests to a cicada for the way she delicately sheds her robe the way a cicada sheds its shell when molting. Cicada exuviae play a role in the '. Cicadas are a frequent subject of ', where, depending on type, they can indicate spring, summer, or autumn.. 's illustrated book ''Cicada'' tells the story of a hardworking but underappreciated cicada working in an office. play ''Appropriate'' takes place on an Arkansas farm in summer, and calls for the sounds of mating cicadas to underscore the entire show.
In musicCicadas are featured in the well-known protest song "''Como La Cigarra''" ("Like the Cicada") written by Argentinian poet and composer . In the song, the cicada is a symbol of survival and defiance against death. The song was famously recorded by , among other Latin American musicians. In North America - Mexico, there is a well-known song, "'" ("The Cicada"), written by , is a song in the tradition that romanticises the insect as a creature that sings until it dies. Brazilian artist with his track "Malvadeza" from the album ''Chão'' creates a song built upon the sound of the cicada that can be heard along the track. Cicada sounds heavily feature on the 2021 album by New Zealand artist . She described cicada song as being emblematic of the New Zealand summer.
In mythology and folkloreCicadas have been used as money, in folk medicine, to forecast the weather, to provide song (in China), and in folklore and myths around the world. In France, the cicada represents the of and the Mediterranean cities. The cicada has represented since . began his collection of fables ''Les fables de La Fontaine'' with the story "La Cigale et la Fourmi" ("The Cicada and the Ant") based on one of 's fables; in it, the cicada spends the summer singing, while the ant stores away food, and finds herself without food when the weather turns bitter. In Chinese tradition, the cicada (, ''chán'') symbolises rebirth and immortality. In the Chinese essay "", the phrase "to shed the golden cicada skin" () is the poetic name for using a decoy (leaving the exuviae) to fool enemies. In the Chinese classic novel ' (16th century), the protagonist Priest of Tang was named the Golden Cicada. In Japan, the cicada is associated with the summer season. For many Japanese people, summer hasn't officially begun until the first songs of the cicada are heard. According to , the song of ', called ''tsuku-tsuku boshi'', is said to indicate the end of summer, and it is called so because of its particular call. In the , the goddess retells the legend of how , the goddess of the dawn, requested to let her lover live forever as an . Zeus granted her request, but because Eos forgot to ask him to also make Tithonus ageless, Tithonus never died, but he did grow old. Eventually, he became so tiny and shriveled that he turned into the first cicada. The Greeks also used a cicada sitting on a harp as an emblem of music. In Kapampangan mythology in the , the goddess of dusk, Sisilim, is said to be greeted by the sounds and appearances of cicadas whenever she appears.
As food and folk medicineCicadas were eaten in , and are consumed today in , both as adults and (more often) as nymphs. Cicadas are also eaten in , , North America, and central Africa, as well as the region of , especially in Ziarat. Female cicadas are prized for being meatier. Shells of cicadas are employed in s. The 17-year "Onondaga Brood" ''Magicicada'' is culturally important and a particular delicacy to the , and are considered a novelty food item by modern consumers in several states.
As pestsCicadas feed on ; they do not or in a true sense, but may occasionally mistake a person's arm for a plant limb and attempt to feed. Male cicadas produce very loud calls that can damage human hearing. Cicadas are not major agricultural pests, but in some outbreak years, trees may be overwhelmed by the sheer numbers of females laying their eggs in the shoots. Small trees may wilt and larger trees may lose small branches. Although in general, the feeding activities of the nymphs do little damage, during the year before an outbreak of periodic cicadas, the large nymphs feed heavily and plant growth may suffer. Some species have turned from wild grasses to , which affects the crop adversely, and in a few isolated cases, females have oviposited on s such as s, vines, trees, , and . Cicadas sometimes cause damage to ornamental shrubs and trees, mainly in the form of scarring left on tree branches where the females have laid their eggs. Branches of young trees may die as a result..
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