Maturing slowly underground for the past 17 years, the cicada is poised to reappear in Potomac beginning sometime this month.
Part of a class of periodic cicadas called Magicicada Brood II, found only on the eastern seaboard, this particular species is unique in its long, prime-numbered life cycle and massive, timed emergence, not to mention its loud chorus, that can sometimes top 90 decibels in a swarm.
This spring’s outbreak is expected to begin in the Carolinas and to work its way up the coast towards Washington, D.C. as the temperatures gradually rise. Peak season should occur in the Potomac area sometime in June. Cicadas are known to achieve incredible population densities, estimated as high as 1.5 million per acre.
According to Michael Raupp, a professor of entomology at the University of Maryland, “In places where they’re going to be present, it’s going to be spectacular. There could be as many as one billion cicadas emerging per square mile.”
Many hypotheses surround the 17-year cicada and its 13-year cousin’s prime-numbered life span. Some scientists surmise that the prime number life cycle foils predators by its unpredictability. Others point to the fact that it’s difficult for predators to have the same life cycle, which would permit them to feast exclusively on cicadas. Aside from the extended developmental phase, the cicadas’ sheer mass and accompanying noise ensures that more of the insects survive to mate and reproduce, ensuring the continuation of the species.
ABOUT MAGICICADA BROOD II
The adult Magicicada Brood II cicada exhibits bright red eyes and a black body. The translucent wings have orange veins. A black “W” shape embellishes the tips of the forewings. Adults typically measure 1-1.3 inches in size, with mature females presenting slightly larger than males.
The story really begins, though, with the cicada “nymph.” Golden-brown in color, the nymph spends most of its 17-year life living underground, sucking root fluids from trees. The nymph matures slowly over its prolonged developmental phase, growing from the size of a small ant to achieve nearly the size of an adult by phase end.
Early in the spring at the end of their 17-year cycle, the nymphs receive a signal to begin constructing exit tunnels to the surface. Known as “turrets,” these tunnels are built out of the soil from which the nymphs will soon emerge. The turrets can often be observed as a group of holes roughly the size of an adult finger located near the roots of deciduous trees.
Once the temperature reaches approximately 64 degrees, the nymphs begin climbing the tunnels in synchronicity and large numbers, shedding their shells to adopt the colors of the adult insect. Spreading their new bright-orange wings, they take flight, searching for mates. Male cicadas band together to form choruses of species-specific calling songs designed to attract females with their sexual allure.
Once mated, females climb trees to lay eggs in a series of nests that they excavate from the tree’s branches. After 6 to 10 weeks, the eggs hatch and the new nymphs drop down from the trees, burrowing back down under the roots, and beginning the whole 17-year process over again. By the time the nymphs have hatched, the adults have died.
According to the website http://magicicada.org, cicadas do not possess a single defensive mechanism. They do not sting or bite. When approached, a cicada will simply fly away. Additionally, cicadas are not poisonous, nor do they transmit disease.
Cicadas, in fact, are actually culinary delicacies for birds and other species, as well as for many humans. Some say they taste like asparagus or shrimp.
Follow “Swarmageddon” on the web
The New York -based Radiolab at http://www.radiolab.org, is preparing for “Swarmaggedon” with its Cicada Tracker Map and how-to information on building your own cicada detector and sharing your observations. Also keeping track of the scene is the National Geographic Society’s e-website, http://www.magicicada.org/map_project/maps.php, with its own database of up-to-the minute cicada sightings.
On the social media side, there’s http://www.cicadamania.com, a website dedicated to “the most amazing insects in the world” and providing online data on when the cicadas are expected in town, what they look like, how they’ll emerge and even a page of audio sound files of cicada songs. For all you tweeters, Cicadamania suggests using hashtag #Brood II and #Cicadas to update your followers on the latest developments.