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2013 Spring Issue 4 (May 3, 2013)

Swarmageddon: A Marvel of Nature

May 5, 2013
By Claire Karban

They’ve been hiding underground for 17 years, sucking sap and maturing. Now, they are digging tunnels through the dirt toward the surface. Soon, they will be swarming by the billions across the East Coast making a 90-decibel buzz. What, you ask? Some are calling it Swarmageddon. You might have heard of it as the re-emergence of the 17-year cicada known as the Magicicada.

The Magicicada is one of seven different species of periodical cicadas, all of which are found in Eastern North America. Some have cycles of 13 years, while others like the Magicicada have 17-year cycles. Scientists believe that the 17-year (or 13-year) life cycle arose as a defense mechanism to throw predators off of their trail.

But how do the cicada’s know when 17 years have passed? Research suggests that the nymphs use annual fluxes in nutrients, as well as plant hormones to gauge the years. And now, after 17 years of counting, the cicadas will once again make their way out of the soil.    

This particular group of cicadas set to emerge is known as the Brood II. For the past 17 years, the Brood II cicada nymphs have been preparing for this spring. Several weeks before their emergence, the nymphs begin constructing their exit tunnel. These tunnels are visible as half-inch diameter holes in the ground, and are currently popping up across the east coast.

Once the exit tunnel is completed, the nymphs will wait until the ground temperature reaches 64o F to ensure that the aboveground climate is suitable for survival. Right on schedule, Magicicadas were first sighted last week, emerging in Greensboro, North Carolina. As temperatures across the east coast continue to warm, more cicadas will crawl out of their tunnels.

Emergence is usually done at after sunset. Cicadas surface, and quickly make their way to nearby vegetation where they molt, or shed their exoskeleton. Immediately after molting, cicadas’ skin appears white and softer. Over the four to six days after molting the skin will harden, and the cicada will begin to exhibit adult behaviors. Once it begins, Swarmageddon will last only four to six weeks as the cicadas, emerge, mate, and lay new eggs that will emerge in 2030.

The Brood II cicadas are perhaps the most popular periodical cicadas because their range includes densely populated areas like Hartford, Philadelphia, Washington, D.C., and New York City. This year’s group is likely to be found in urban areas like Central Park.

There is no need to worry; cicadas are not dangerous. Although it may be unnerving to get caught below a swarm of loud cicadas, the insects themselves do not bite or sting. Cicadas can cause problems for owners of fruit orchards or nurseries, but they do not cause widespread harm.

In fact, from an ecological standpoint, the cicadas are beneficial. The nymphs aerate the ground as they emerge, and then provide a nutritional feast for birds and other species. Even humans might reap some culinary benefits from the Magicicadas.  

Around the world, cicadas are often important sources of food, and several entomologists have put together recipes for incorporating this year’s Magicicadas into your diet. Cicadas are said to taste like asparagus or avocado, and can be thrown onto pizzas or fried and tossed into salads. (I’m serious. Visit http://www.newsdesk.umd.edu/pdf/cicada%20recipes.PDF for recipes.)

In the words of Entomologist Michael J. Raupp, “Without a doubt, [cicadas] are a true marvel of nature and one that should be enjoyed whenever possible.”  

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