Home » Science » Magic Cicada Invasion Of 2011 (Updated September 2012)

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Mating cicadas (Picture taken by Ajay, June 6, 2008)

2011 was the year for the emergence of brood XIX of the periodical cicadas. Several species emerge together, all belong to the genus Magicicada thus, the term magic cicada. These amazing creatures live underground 13 or 17 years before emerging by the trillions over wide areas. They are completely harmless and actually for those that are not allergic to shrimp and lobster, can make a delicious snack.

Each year class is given a different number; the Brood XIX of 2011 emergence ws the largest by far of the 13 year broods. They'll be found across the Midwest and Southern states as you can see on the following map from the University of Michigan. NOTE: they are also found in a tiny area at the southern end of the Delmarva Peninsula.

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These amazing insects are only found in eastern North America, nowhere else in the world. They are completely harmless and actually are in considerable trouble because they are facing an attack by invasive species, creatures that have been brought into the United States to which they have no defense. Of the three most noxious invasive bird species, pigeons, starlings and sparrows, it is the latter two with their vast numbers, which have the ability to severely impact these insects. At least two broods have already been driven to extinction.

One of the more interesting uses of these creatures is as background noise for science fiction movies, especially those featuring flying saucers and giant insects. I guess, when Hollywood was trying to decide the sound that a giant ant should make (“Them”-a 1954 monster movie comes to mind) they figured that millions of screaming cicadas would equal one bus sized ant.

Magicicadas, as stated above are completely harmless, they feed on tree roots underground, but grow so slowly they do not cause significant damage. When they finally emerge, often as many as 1 1/2 million per acre, they only live a few weeks. Climbing into the treetops, to warm themselves in the mid-spring sun, they produce a noisy chorus which once heard, will always be remembered. They are very different from the annual, so-called dog day cicadas of the genus Tibicen which make the typical loud buzzing noise, which remind you that summer is ending fairly soon. After they mate, the females will deposit their eggs in the thin branches, which do suffer some damage and often break off and hang from the tree with brown leaves showing where the cicadas have deposited their eggs. (This is called flagging) The tree looks a little bit sad for a while but the following year it actually grows very nicely after this natural pruning and also from the nutrition left behind after all of the cicadas die shortly after egg laying. The only problem caused by the Magicicadas is to very young fruit trees which could lose most of their tiny branches so, if you live in a cicada area, hold off on planting such trees or else cover them with some netting.

The Magicicadas emerge much earlier than the annual ones and have a very striking appearance, shiny black with ruby red eyes. I do not know the reason for the red eyes but I am quite positive that the black color is for them to absorb as much sunlight. Warmth is often in short supply in the treetops during the relatively cool days of May when they flying about singing and hunting for mates.

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Magicicadas from brood XIV (Taken by AJay, June 6, 2008) (these are from the species Magicicada septendecim which means in Latin "the magical cicadas of 17 years” I really like that name)

the principal species this year will be Magicicada Tredecim (magic cicadas of 13 years)

One of the most interesting things about Magicicadas, is that they make very little effort to flee when you try to pick them up. Apparently their strategy is "predator satiation". They emerge in such vast numbers that their normal predators are soon completely stuffed with cicadas and the rest, live to mate and lay eggs. While they spend either 13 or 17 years underground depending on which broods they belong to, above ground, they live but a few weeks. They are by far, the longest lives of all insects and as a unique phenomenon in eastern North America, I hope that those reading about them will not fear them and especially please don't slaughter them with insecticides. They do not eat leaves, they only drink dilute juices from the leaves and in fact, if you stand in the right place with the sun shining through the trees you can see fine sprays coming from the treetops. The cicadas must pee because they drink such a dilute source of nutrition. After they die, they decay right around the trees from which they emerged, molted, and later produced their unforgettable mating songs. In this way they are returning the nutrients right back to the tree that fed them for all of those years. It is certainly a fascinating example of natural recycling.

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Shed exoskeletons of cicada nymphs, left behind as they climbed this tree. (By AJay, June 7,2008)

This gives some idea of the incredible numbers of these insects during an emergence.

  An interesting characteristic of Magicicada emergences is the phenomenon of "Straggling" This is the emergence of varying numbers of nymphs on "Wrong Years" especially 4 years before or after  the expected year. Chris Simon is now doing a research project on DNA variations of stragglers. A friend and myself were able to capture and preserve a number of "Stragglers" for this important research. They are now in pure ethanol in my freezer and will shortly be sent to Chris for her interesting efforts. The project, unfortunately, has been delayed because of the serious  injury to two of her researchers in an arson attack. I hope for the quick recovery of her dedicated helpers Kathy and Dave.

Picture of a 21 year old Brood XIV Straggler, from May of 2012

 

For More reading on this subject:

UMMZ Periodical Cicada Page

Cicada Mania: cicada photos, sounds & video, Brood XIX cicadas

 

World #1 Cicada expert Chris Simon—EEB Faculty: Chris M. Simon

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