Friday, May 31, 2013

CICADAS: MORPHOLOGY, BIOLOGY, ETC.


CICADIDAE MAGICICADA
Entomology and Morphology

Cicadas are a group of large flying insects of the order Hemiptera, suborder Auchenorrhyncha. This large family (Cicadidae) of invertebrates consists of over two thousand five hundred species, occupying every continent except Antarctica. Cicadas spend the majority of their lives underground as nymphs, burrowing deep into the earth and feeding off tree roots. Over a period of three to nineteen years (depending on species) the nymphs mature and emerging from their subterranean catacombs simultaneously in large swarms to molt into their winged adult forms. Humans and cicadas share a long and magical mythology. The interactions and legends our two species share stretches across recorded history, touching almost every civilization and corner of this planet. Whether being treated as little more than a valuable source of protein or being revered as messengers of the gods our two species are intimately intertwined. A fractal exchange stretching back into the depths of antediluvian time.  

Life Cycle and Behavior

The pregnant  female cicada cuts slits into small branches using her ovipositor, a sharp, knife-like structure on the end of her abdomen. In these shallow grooves she deposits her eggs, small white structures similar in shape to a grain of rice. Once the eggs hatch the newborn nymphs drop to the ground and begin the arduous task of burrowing into the ground. The nymph’s burrow is generally only a foot or so deep, however they have been know to dig as deep as three meters. Once underground the nymphs tunnel until they locate a tree root and feed off of it using a sharp proboscis. A cicada’s diet consists exclusively of tree sap, specifically the xylem. They feed mostly off deciduous trees such as oaks, maples, willows, etc. It is believed that the nymphs are able to “taste” seasonal differences in the sap while underground. Some entomologists believe that this may be how they time their group exodus from their dark tunnels when they molt into adults.

There are two main groups of cicadas, Magicicada or periodical species and Tibicen or “dog-day” varieties. The Tibicen broods are staged so that some emerge every summer. The subterranean life cycle of these species varies from two to seven years depending on species. (It is interesting from an occult perspective to note that the vast majority of cicadas, Magicicada and Tibicen, have multi-year life cycles that are prime numbers. 2,5,7,13, 17,and 19…) Upon receiving their mysterious “signal” the nymph's begin burrowing up and emerge from the ground over a period of several days or all at once in large broods. The cicadas then climb the nearest tall object or tree (frequently the same one they fell from years before) and latch onto it. Once secure, the nymphs undergo their final metamorphosis and molt into their adult forms. A line breaks open down the spine and the winged adult wiggles out of its exoskeleton in a pulsing backbend. The soft bodied adult clings to its former skin and waits. In a span of minutes its skin darkens  and begins transforming into a protective chitlin carapace and its compressed wings are unfurled as liquid is pumped into them. It may take up to 6 days for Magicicada species to completely harden and embrace their new bodies, their skin crystalizing into a regal new armor. The newborn adult then leaves its chthonic husk behind and continues its ascent into the upper reaches of the tree.

The newly hatched imago’s fly upwards and join together in large choruses consisting of thousands of singing males and clicking females. The noise generated by a large brood emerging at the same time can be deafening. The males sing a species specific song until a female approaches and responds by clicking her wings together. Upon hearing the female’s receptive click the male changes his song to a more seductive melody and approaches her to mate. Once mating has concluded the female flies away. She will land on a nearby tree or branch and cut small, V-shaped slits into the bark. Into these slits she will deposit twenty or so eggs per incision until she has carefully laid them all, usually totaling somewhere around six hundred eggs.

Within weeks of their emergence and metamorphosis all the adult cicadas are dead. Their bodies fall from the trees and litter the forest’s floor providing a feast for other animals as well as decaying and feeding the earth itself. The adult life of a cicada is exceedingly brief in comparison to the years spent as a nymph; toiling away in the dark and silent ground. Years and years of patient silence culminating in a Dionysian month of flying, fucking, singing and worshiping the sun. Then, just as quickly as they emerged, death claims them. One and all. 

Although this abrupt ending may strike you as somewhat bitter-sweet, the cicadas have lived, loved and fulfilled their genetic promise. Several weeks after their parents have passed away the eggs hidden in the branches above begin to hatch.  The tiny nymphs wriggle free of the wood and drop from their lofty nurseries to the ground below. This newborn brood of  insects then begins their incredible life cycle anew. Upon landing on the forest floor, The nymphs immediately burrow deep underground to wait in total darkness for the next thirteen or seventeen years. Waiting in the dark for that mysterious signal, waiting for their day to sing, fly and worship.

Morphology

Cicadas go through several distinct life stages on their path to adulthood. The nymphs emerge from their eggs encapsulated in a tight embryonic skin making them resemble a small fish or slug. Upon exiting the wooden hole cut by its mother the nymph promptly sheds its jacket and frees its legs. The newborn nymphs are extremely small but already possess strong digging forearms and the will to use them. The nymphs immediately fall to the ground and crawl into the first hole or crack in the ground that meets their requirements. Over the next several months the young insects will burrow deeper and deeper into the ground. They start feeding by sucking sap from small rootlets near the surface; gradually working their way down to larger tree roots as they increase in size and appetite. The nymphs go through five molts or “instars” during their time underground, usually spending several years between each stage feeding and enlarging their burrows. After each molting the nymph emerges from its old skin larger and more “tank-like”. The forelegs in particular become much more formidable at the second instar stage. These front legs are highly specialized claws which strongly resemble a pick axe and are used in the exact same fashion; hacking through the tough ground in search of more roots to feed from. 

During the nymph stage of a cicadas life they are completely subterranean. They have a powerful and compact body, no wings (In the fourth and fifth instar stage vestigial wing “pads” become apparent.) and though they do possess eyes at this stage they are noticeably smaller than in their adult forms as they have no need for them.  At no point in their life do they possess a true set of jaws, simply a long, sharp proboscis similar to their cousins the aphids. This proboscis is tucked tightly against their stomach when not in use but can fold down and extend to allow the nymph to pierce a root of its parent tree and suck the sap which flows within. Once the nymph molts into its fifth instar stage, prior to emerging from the ground, it is roughly an inch to an inch and a quarter  in length. It also more closely resembles its final adult form with large, well developed eyes, obvious wing pads, proportionately smaller front claws and the wide, fat body unique to its species.

Upon receiving its mysterious signal to emerge from the ground, the cicada nymphs make their way to the surface in huge numbers. These mass emergences can be staggered over several days or happen all at once (depending on species and other unknown factors.). Upon breaking free of the earth the cicada nymphs immediately make their way to any convenient tree or vertical surface and climb up it to molt into their final adult forms. There are numerous accounts of cicadas emerging into basements and root cellars with earthen floors. Due to the length of time it takes many cicadas to reach maturity (a decade or more) it is not uncommon for a house or other building to be constructed on top of an immature brood, only to have the nymphs swarm into the buildings and surrounding area. Once reaching a convenient and secure location the nymphs latch onto whatever vertical surface they happen to climb and begin the delicate operation of molting into their adult form. The exoskeleton of the nymph splits open down the mesothorax (upper back) and the cicada wriggles out of its old skin in an elegant backbend. Once free, it clings to its securely anchored husk and begins the process of inflating its wings by pumping fluid into the veins that adorn the flattened wings, within several minutes to an hour the wings fully unfurl and harden along with the exoskeleton of the newly born adult. Once this magical crystallization occurs the newly born adult is free to fly into the upper reaches of the forest and begin serenading it’s female brood mates in a musical endeavor to further its genetic promise. 

The adult cicada (in entomological parlance, an Imago) is a truly beautiful and unique invertebrate. The adults body is 1 to 4 inches in length, with developed eyes, wings, and unique structures for making sound.  The cicada imago varies greatly in color depending on species and geographic location. Most common varieties are green or brown  in
coloration or black with red eyes in the case of the magicada. There
are also numerous tropical varieties that come in a rainbow of bright
colors. The fully formed adults are physically similar to their nymph
stages the primary difference being that they are now capable of
flight and song.

 Most species of noise-producing insect make sound by stridulation;
the process of rubbing two structures against each other such as the
legs or wings. However, the adult male cicada makes its unique song by
using a complex structure in its abdomen known as a tymbal. the male
cicadas abdomen is mostly hollow and acts as a resonance chamber. on
both sides of the abdominal base there is a membrane internally
connected to a pair of muscles. These muscle rapidly flex and release
"popping" the membrane in and out and generating a loud sound. (think
of it as popping a drink or jam lid with your fingers very quickly.)
The cicada can modulate it's song by slowing and accelerating these
muscular contractions as well as raising or lowering its body off the
ground. Cicadas are among the loudest of all insects some varieties
can produce sounds in excess of 120 decibels, loud enough to cause
permanent hearing damage to humans. A mass brood exodus of thousands
of singing cicadas can be deafening.

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