When winter is at its height, it’s hard to think of something set to happen in the spring or summer as very relevant. However, the warmer seasons are only a few months away and experts expect a rare phenomenon to occur in 15 states across the USA this year. For the first time since 2004, millions of cicadas will re-emerge from underground and swarm the country.
The cicada swarm in question is known as Brood X, or the Great Eastern Brood of periodical cicadas. Unlike the more common annual cicadas, which are green, periodical cicadas have black bodies and bright red eyes. Although these insects can look intimidating due to their size (2.5" in length with a 3" wingspan) and ear-piercing buzz, they are mostly harmless.
Image Source: Wikimedia Commons
“The end of May through June, it can get pretty loud – if you are in an area where they are numerous, there can be hundreds of thousands, or millions, of them,” said Howard Russell, an entomologist (insect scientist) at Michigan State University, to USA Today. The states that are expected to see the emergence of the periodical cicadas are Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, Michigan, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, as well as Washington, D.C.
The Brood X cicadas emerge en-masse every 17 years when the soil temperatures reach 64 degrees Fahrenheit (18°C), but they can delay their emergence by a few days if the weather is rainy, or otherwise sub-optimal. This time-cycle is one of nature’s great mysteries. Experts are yet to find a definitive answer as to why periodical cicadas aren’t triggered to resurface in, say, the 15th or the 16th spring.
But just because the bugs cannot be seen doesn't mean they are in hibernation. They have been living underground, feeding on sap from tree roots. While living below the surface, the cicadas exist in “nymph” form with white bodies and no wings. It takes about 5 days after their emergence for their exoskeleton to harden and turn black.
The distinctive buzzing noise created by the swarm is due to the male insects trying to attract a mate. After mating, female cicadas will lay eggs in soft, new twigs, using a sharp organ called an ovipositor to cut into the branches and place her fertilized eggs inside. That makes the periodical cicadas quite harmful for tree nurseries and orchards.
“You can’t spray enough pesticide to kill them all without also wiping out everything else in the environment,” Cooley said. What is the solution, then? According to Cooley, it’s putting nets or bags over trees for the period of time the cicadas are active, until around the beginning of July. The eggs hatch in six to ten weeks. The tiny nymphs fall on the ground, burrowing themselves into the soil, and so begins another 17-year cycle.
This is pretty much the only threat the cicadas pose. Their loud buzz may be bothersome, but besides that, they are harmless - they aren’t drawn indoors and they don’t bite.
Apparently, the most common question people have about the cicadas is how to kill them. But Cooley and other experts are urging people to refrain from doing that. "The answer is: don't," he said. "They are one of our natural wonders. Enjoy them while you have them."
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