Monday, September 14, 2020 – Cicadas
- Mary Reed
- Sep 15, 2020
- 10 min read
It is early in the morning, before sunrise. All the birds are silent, resting their voices for a new day. But there are other animals who are not asleep at this hour. In fact, they seem to be wide awake and expressing themselves VERY LOUDLY. I am talking about cicadas, that humming chorus of insects. Their song is high-pitched, sounding almost like a rattlesnake or the whirr of bicycle spokes with a plastic playing card clipped to them. When many of them join together in a great choir, the sound is quite soothing. I imagine them saying, “Welcome to our world. Enjoy the beauty of the outdoors and all nature has to offer.”
According to Wikipedia, the cicadas are a superfamily — the Cicadoidea — of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two families, Tettigarctidae — with two species in Australia — and Cicadidae, with more than 3,000 species described from around the world; many species remain undescribed.
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 drumlike tymbals, corrugated exoskeletal structures. 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 i.e., able to avoid observation or detection by other animals. 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 genus, the periodical cicadas spend most of their lives as underground nymphs, emerging only after 13 or 17 years. The unusual duration and timing of their emergence may reduce the number of cicadas lost to predation, both by making them a less reliably available prey (so that any predator who evolved to depend on cicadas for sustenance might starve waiting for their emergence), and by emerging in such huge numbers that they will satiate any remaining predators before losing enough of their number to threaten their survival as a species.
The annual cicadas are species that emerge every year. Though these cicadas have life cycles that can vary from one to nine or more years as underground larvae, their emergence above ground as adults is not synchronized, so some members of each species appear every year.
Taxonomy and diversity
The largest species is the Malaysian emperor cicada; its head-body length is 2.8 inches and wingspan is up to about 8 inches. Cicadas are notable for the great length of time some species take to mature.
At least 3,000 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 endemism — or ecological state of a species being native to a single defined geographic location, such as an island, nation, country or other defined zone — 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, stretching across all of Eurasia north of the foothills of the Himalayas and North Africa. A few species are found in southern Europe, and a single species was known from England, the New Forest cicada, which also occurs in continental Europe.
Many of the North American species are the annual, jarfly or dog-day cicadas — 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 lifecycle 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 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 — the Kermadec Islands, the Chatham Islands. One species is found on Norfolk Island which technically is part of Australia. The closest relatives of the New Zealand cicadas live in New Caledonia and 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.
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 recognized as a cicada-like form and renamed Palaeontina oolitica.
Biology
Cicadas are large insects made conspicuous by the courtship calls of the males. They are characterized by having three joints in their arthropod leg, and having small antennae with conical bases and three to six segments, including bristle- or hair-like structures 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 hindwing. 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 adult insect, known as an imago, is 1 to 2 inches in total length in most species. 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 or simple eyes 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 middle thoracic segment has an operculum — or stiff structure resembling a lid or a small door that opens and closes — 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 or tube-like organ used for the laying of eggs. 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, they leap several millimeters 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.
Cicada sound-producing organs and musculature: a. Body of male from below, showing cover-plates b. From above, showing drumlike tymbals c. Section, muscles that vibrate tymbals d. A tymbal at rest e. Thrown into vibration, as when singing
Song
The "singing" of male cicadas is produced principally and in the majority of species using a special structure called a tymbal, a pair of which lies below each side of the anterior abdominal region. The structure is buckled by muscular action and being made of resilin — an elastomeric protein — unbuckled rapidly on muscle relaxation and the rapid action of muscles produces their characteristic sounds. Some cicadas, however, have mechanisms for producing sound by rubbing together body parts, sometimes in addition to the tymbals. Here, the wings are rubbed over a series of midthoracic ridges. 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 sound box. By rapidly vibrating these membranes, a cicada combines the clicks into apparently continuous notes, and enlarged chambers derived from the windpipe serve as resonance chambers 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.
During sound production, the temperature of the tymbal muscles was found to be significantly higher than the average temperature of the natural habitat of 84 °F. Many cicadas sing most actively during the hottest hours of a summer day; roughly a 24-hour cycle. 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.
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 are known to call from hollows made at the base of the tree below the ground level.
Although only males produce the cicadas' distinctive sounds, both sexes have membranous structures called tympana 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 dB which is among the loudest of all insect-produced sounds. The song is loud enough to cause permanent hearing loss 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. 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.
In art and literature
Cicadas 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 BC.).[d] They are described by Aristotle in his "History of Animals" and by Piny the Elder in his "Natural History;" their mechanism of sound production is mentioned by Hesiod in his poem "Works and Days": "when the Skolymus 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 "Romance of the Three Kingdoms," Diaochan took her name from the sable tails and jade decorations in the shape of cicadas, which adorned the hats of high-level officials. In the Japanese novel "The Tale of Genji," 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. A cicada exuvia plays a role in the Chinese graphic novel "Winter Cicada." Cicadas are a frequent subject of haiku, where, depending on type, they can indicate spring, summer or autumn. Shaun Tan's illustrated book "Cicada" tells the story of a hardworking but underappreciated cicada working in an office.
In music
Cicadas are featured in the well-known protest song "Como La Cigarra" ("Like the Cicada") written by Argentinian poet and composer María Elena Walsh. In the song, the cicada is a symbol of survival and defiance against death. The song was famously recorded by Mercedes Sosa, among other Latin American musicians. Another well-known song, "La Cigarra" ("The Cicada"), written by Raymundo Perez Soto, is a song in the mariachi tradition that romanticizes the insect as a creature that sings until it dies.
The Brazilian artist Lenine 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.
In mythology and folklore
Cicadas 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 folklore of Provence and the Mediterranean cities.
The cicada has represented insouciance since classical antiquity. Jean de La Fontaine 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 Aesop'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.
The cicada symbolizes rebirth and immortality in Chinese tradition. In the Chinese essay "Thirty-Six Stratagems" the phrase "to shed the golden cicada skin" is the poetic name for using a decoy (leaving the exuvia) to fool enemies. In the Chinese classic novel “Journey to the West” (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 Lafcadio Hearn, the song of Meimuns opalifera, called tsuku-tsuku boshi, is said to indicate the end of summer, and it is called so because of its particular call.
In the Homeric “Hymn to Aphrodite,”, the goddess Aphrodit retells the legend of how Eos, the goddess of the dawn, requested Zeus to let her lover Tithonus live forever as an immortal. 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 Philippines, the goddess of dusk, Sisilim, is said to be greeted by the sounds and appearances of cicadas whenever she appears.
As food and folk medicine
Cicadas were eaten in Ancient Greece, and are consumed today in China, both as adults and (more often) as nymphs. Cicadas are also eaten in Malaysia, Burma, North America, and central Africa, as well as the Balochistan region of Pakistan, especially in Ziarat. Female cicadas are prized for being meatier. Shells of cicadas are employed in traditional Chinese medicines. The 17-year "Onondaga Brood" Magicicada is culturally important and a particular delicacy to the Onondaga people.
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