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Periodical Cicadas:
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Cicadas are insects belonging to the order Hemiptera, family name Cicadidae. They have piercing, sucking mouthparts and uniformly thickened forewings that overlap slightly at the tips. Others in Hemiptera include leaf hoppers, whiteflies and aphids. Cicadas spend most of their lives underground feeding on the sap of tree roots. When the soil temperature maintains a steady 64 degrees, they emerge, shed their final skins, harden, move up into trees, mate, and die after a month or less. Translated from Latin, cicada is "tree cricket," and the males are known for their loud mating songs. Dan Mozgai of the Cicada Mania website has recorded periodical cicadas at 109 decibels, although other reports have groups at 120 dB, approaching the pain threshold for humans!

Periodical cicadas are the genus Magicicada, distinguished by their red eyes and orange wing veins, and are found only in eastern North America. They are different from the more familiar "annual" or "dog-day" cicadas (although those also usually have multiple-year life cycles) that emerge later in the summer throughout the U.S. The development of periodical cicadas is synchronized, while that of annual cicadas is not. Almost all periodical cicadas grow and mature into adults at the same time, which is why we witness such large groups every 13 or 17 years. With numbers in the millions, billions, even trillions, the cicadas have an advantage over their predators who are trying to feast on them. According to biologist Keith Clay, "birds, rodents, small mammals, even snakes, lizards, and fish will feed heavily on cicadas when they are out."

Specific groups of periodical cicadas are called "broods." There are twelve broods of 17-year cicadas and three broods of 13-year that appear in different years. In May of 2004 the Washington, D.C. area witnessed the emergence of the 17-year periodical cicadas in Brood X. Brood X returns in 2021, although possible "stragglers" appeared in May, 2017 in D.C. and the surrounding counties in Virginia and Maryland, as well as in Ohio, Indiana, Tennessee, Kentucky, Pennsylvania, Delaware and New Jersey. Stragglers are subsets of periodical cicadas that develop and emerge "off cycle" in years before or after their brood is expected. A four-year gap is typical of 17-year periodical cicadas. Some entomologists wonder if climate change is affecting them and causing them to grow faster (acceleration), and there will be more research focused on that. However, there were even accelerations reported in the 1898 USDA document by C.L. Marlatt: The Periodical Cicada. An Account Of Cicada Septendecim, Its Natural Enemies And The Means Of Preventing Its Injury. External Link



Gross, Rachel E. What’s up with cicadas? Slate, May 23, 2016.
   This is a fun and informative article!
External Link

Ito, Hiromu, et al. Evolution of periodicity in periodical cicadas. Scientific reports 5, September 14, 2015.
   A more deeply scientific article for serious readers. External Link

Roach, John. Cicada recipes: bugs are low-carb, gluten-free food. National geographic, May 15, 2014.
   They’re crunchy with an asparagus-like taste. Sold on skewers in China. Note the author’s last name! External Link

Valdes, Robert. How cicadas work. How stuff works (website). April 13, 2004.
   How they mate and what happens next. And, by the way, they won’t hurt you. External Link



Egan, Rory B. Bugbios: Cicada in Ancient Greece. Cultural entomology digest. November 1994.
   Egan discusses cicada references in Greek literature and mythology. External Link

Riegel, Garland. Bugbios: Cicada in Chinese folklore. Cultural entomology digest. November 1994.
   A discussion of the use of the cicada in Chinese medicine and the symbolism in Chinese art and artifacts. External Link



BugGuide External Link
   Brought to us from the Iowa State University Department of Entomology.

Cicada Central External Link
   This website from the University of Connecticut is designed to be a clearinghouse for scientific information about cicadas.

Cicadamania External Link
   All things cicada—"the most amazing insect in the world!" There are recordings of the various broods singing, too. This website was started in 1996 and still run by Dan Mozgai.

Cicadas of the Mid-Atlantic External Link
   Here is the official website for the Mid-Atlantic Cicada Database Project where you can report your sightings and track what’s going on. There’s much more to explore, as well as another chance to listen to those cicada choruses.

Magicicada External Link
   Sightings, general information, citizen science, science projects, and even Facebook and Twitter!

Maryland: Bug of the Week External Link
   Professor of Entomology, Michael Raupp maintains this column. Click on archives and search for cicadas.

National Geographic Cicada Page (for kids) External Link
   A great cicada photo here!

The University of Michigan Museum of Zoology, Insect Division External Link
   A link to their periodical cicada page with loads of information.

Revised by Stephanie Marcus, June 2017

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   June 30, 2017
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