The Cicada - pronounced
si-keida is an insect of the order Hemiptera, suborder Auchenorrhyncha, in the
superfamily Cicadoidea, with large eyes wide apart on the head and usually
transparent, well-veined wings. I first met them whilst living in Malta
(1960-1964) and apparently called them cheese-bugs. There are about 2,500
species of cicada around the world, and many remain unclassified. Cicadas live
in temperate to tropical climates where they are among the most widely
recognized of all insects, mainly due to their large size and remarkable
acoustic talents. Cicadas are sometimes colloquially called "locusts", although
they are unrelated to true locusts, which are a kind of grasshopper, they are
also known as "jar flies". Cicadas are related to leafhoppers and spittlebugs,
in parts of the southern Appalachian Mountains they are known as "dry flies"
because of the dry shell they leave behind.
Cicadas are benign to humans and do not bite or sting, but can be pests
to several cultivated crops. Many people around the world regularly eat cicadas:
the female is prized as it is meatier. Cicadas have been (or are still) eaten in
Ancient Greece, China, Malaysia, Burma, Latin America, and the Congo. In North
China, cicadas are skewered or stir fried as a delicacy. Shells of cicadas are
employed in the traditional medicines of China.
The name is a direct derivation of the Latin cicada, meaning "buzzer". In
classical Greek it was called a tettix, and in modern Greek tzitzikas - both
names being onomatopoeic.
Taxonomy
Cicadas are arranged into two families: Tettigarctidae and Cicadidae. The
largest cicadas are in the genera Pomponia and Tacua. There are some 200 species
in 38 genera in Australia, about 450 in Africa, about 100 in the Palaearctic,
and exactly one species in England, the New Forest cicada, Melampsalta montana,
widely distributed throughout Europe. There are about 150 species in South
Africa.
Most of the North American species are in the genus Tibicen - the annual
or dog-day cicadas -so named 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 thirteen to seventeen years and emerge in
large numbers.
Description: The adult
insect, sometimes called an imago, is usually one to two inches long, although
some tropical species - the
Malaysian Pomponia imperatorial can reach six inches. 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. Also, commonly overlooked,
cicadas have three small eyes located on the top of the head between the two
large eyes that match the colour of the large eyes, giving them a total of five
eyes. Desert cicadas are also among the few insects known to cool themselves by
sweating, while many other cicadas can voluntarily raise their body temperatures
as much as twenty two degrees centigrade above ambient
temperature.
Male cicadas have loud noisemakers called "timbals" on the sides of the
abdominal base. Their "singing" is not the stridulation (where two structures
are rubbed against one another) of many other familiar sound-producing insects
like crickets: the timbals are regions of the exoskeleton that are modified to
form a complex membrane with thin, membranous portions and thickened "ribs".
Contracting the internal timbal muscles produces a clicking sound as the timbals
buckle inwards. As these muscles relax, the timbals return to their original
position producing another click. The interior of the male abdomen is
substantially hollow to amplify the resonance of the sound. A cicada rapidly
vibrates these membranes, and enlarged chambers derived from the tracheae make
its body serve as a resonance chamber, greatly amplifying the sound. They
modulate their noise by wiggling their abdomens toward and away from the tree
that they are on. Additionally, each species has its own distinctive
song.
Average temperature of the natural habitat for this species is
approximately 29 degrees centigrade. During sound production the temperature of
the tymbal muscles were found to be slightly higher. Cicadas like heat and do
their most spirited singing during the hotter hours of a summer
day.
Although only males produce the cicadas' distinctive sound, both sexes
have tympana, which are membranous structures used to detect sounds and thus the
cicadas' equivalent of ears. Males can disable their own tympana while calling.
Adult cicadas have a sideways-ridged plate where the mouth is in normal
insects.
Some cicadas produce sounds up to 120 decibels "at close range", among
the loudest of all insect-produced sounds. Conversely, some small species have
songs so high in pitch that the noise is inaudible to humans. Species have
different mating songs to ensure they attract the appropriate mate. It can be
difficult to determine which direction cicada song is coming from, because the
low pitch carries well and because it may, in fact, be coming from many
directions at once, as cicadas in various trees all make noise at
once.
In addition to the mating song, many species also have a distinct
distress call, usually a somewhat broken and erratic sound emitted when an
individual is seized. A number of species also have a courtship song, which is
often a quieter call and is produced after a female has been drawn by the
calling song.
Life cycle: After mating,
the female cuts slits into the bark of a twig, and into these she deposits her
eggs. 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. Most
cicadas go through a life cycle that lasts from two to five years. Some species
have much longer life cycles, e.g., such as the North American genus,
Magicicada, which has a number of distinct "broods" that go through either a
seventeen year or, in the American South, a thirteen year life cycle. These long
life cycles both happen to be prime numbers, perhaps developed as a response to
predators such as the cicada killer wasp and praying mantis. A predator with a
shorter life cycle of at least 2 years could not reliably prey upon the
cicadas.
Cicadas live underground as nymphs for most of their lives, at depths
ranging from about 30 cm (1 ft) up to 2.5 m (about 8½ ft). The nymphs feed on
root juice and have strong front legs for digging.
In the final nymphal instar, they construct an exit tunnel to the surface
and emerge. They then moult on a nearby plant for the last time and emerge as
adults. The abandoned skins remain intact clinging to the bark of trees. They
live above ground for 5-6 weeks, then they mate, and then they die. If that's
the case I would rather forego the rudies and stay underground. Not a man comment.
Predation: Cicadas are
commonly eaten by birds, but Massospora cicadina (a fungal disease) is the
biggest enemy of cicadas. Another known predator is the Cicada Killer
Wasp. In eastern Australia, the native freshwater fish Australian
Bass are keen predators of cicadas that crash-land on the
surface of streams.
Some species of cicada also have an unusual defense mechanism to protect
themselves from predation, known as predator satiation. Essentially, the number
of cicada in any given area exceeds the amount predators can eat; all available
predators are thus satiated, and the remaining cicadas can breed in
peace.
Cicadas inhabit both native and exotic plants including tall trees,
coastal mangroves, suburban lawns, and desert shrubbery. The great variety of
flora and climatic variation found in north-eastern Queensland results in its being the richest region for the spread of different
species. The area of greatest species diversity is a sixty mile wide region
around Cairns. In some areas they are preyed on by the
cicada-hunter - Exeirus lateritius which stings and stuns cicadas high in the
trees, making them drop to the ground where the cicada-hunter mounts and rides
them, pushing with its hind-legs, sometimes over a distance of a hundred meters,
till they can be shoved down into its burrow, where the numb cicada is 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.
The Cicada emerging and the perfect skin left on the
tree.
Cicada and symbolism: In
France, the cicada is used to represent the folklore of
Provence and Mediterranean cities (despite the fact some species live in Alsace or the Paris Basin). A summer insect (at least in temperate countries), the cicada has
represented insouciance - that is nonchalance or indifference since antiquity.
Jean de la Fontaine began his collection of fables Les
fables de La Fontaine with the story 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.
Cicada songs are regularly used in Japanese anime to indicate that a scene is taking place in the summer.
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 scarf the way a cicada sheds its
shell when moulting. They are also a frequent subject of haiku, where, depending on type, they can
indicate spring, summer, or autumn.
In China the phrase 'to shed off the golden cicada skin' is the poetic
name of the tactic of using deception to escape danger, specifically of using
decoys (leaving the old shell) to fool enemies. It became one of the thirty six
Chinese stratagems. In the Chinese classic Journey to the West, the protagonist Priest of Tang was named the Golden Cicada; in this
context the multiple shedding of shell of the cicada symbolizes the many stages
of transformation required of a person before all illusions have been broken and
one reaches enlightenment.
In 2004, "cicada" ranked 6th in Merriam-Webster's Words of the
Year.