Since 1803, this will be the first time that insects from these two broods will emerge simultaneously in the United States.
A Rare Event in 221 Years of America
The New York Times reports that this will be a rare event occurring in the United States from early to late April. More than 1 trillion cicadas from two different broods will emerge across approximately 16 states in the U.S. Many are calling this event the “largest disaster” in America in 221 years.
Dr. Jonathan Larson from the University of Kentucky states that these are periodical cicadas (Magicicada), some of the longest-living insects in nature. They are divided into two main groups: Brood XIX, or Great Southern Brood – which emerges every 13 years, and Brood North Illinois, or Brood XIII, which emerges every 17 years.
More than 1 trillion cicadas from two different broods will emerge across approximately 16 states in the U.S. (Photo: CNN)
These two species of cicadas spend most of their lives underground, developing by sucking sap from tree roots. After their 13- or 17-year cycle, they will use their front legs to dig and emerge from the ground. A few days after appearing and molting, the males will start producing sounds to attract mates, lay eggs, and die within a few weeks, completing their maturation process.
Floyd W. Shockley, an entomologist, shared with Smithsonian Magazine that because both 13 and 17 are prime numbers, these two types of cicadas can only emerge together once every 221 years. The last time these two groups emerged simultaneously was during Thomas Jefferson’s presidency. This event is also known as a “double emergence,” where Americans will witness more than 1 trillion cicadas appearing in many places.
What Are Cicadas?
Cicadas, also known as “magic flies,” are a superfamily of insects with large heads and wings that have many veins. There are about 2,500 species of cicadas worldwide, found in both temperate and tropical regions. Cicadas are among the most recognizable insects due to their larger size, distinct head shape, and the loud sounds they make throughout the summer. In the Appalachian region, Americans refer to cicadas as “dry flies” because their exoskeletons remain intact and dry after molting. Cicadas do not sting, bite, and are harmless to humans.
As they reach the final transitional stage at the end of the nymph stage, cicada nymphs dig a tunnel to the surface and emerge. (Photo: CNN)
After mating, female cicadas dig small grooves into the bark of branches and lay their eggs there. A female can repeat this process several times until she has laid hundreds of eggs. Once the eggs hatch, the cicada nymphs fall to the ground and burrow deep into the soil. When reaching the final transitional stage to end the nymph stage, the cicada nymphs dig a tunnel to the surface and emerge. They then molt one last time on a nearby tree to become adult cicadas, leaving their exoskeletons attached to the bark.
A few days after emerging and molting, the males will start producing sounds to attract mates, lay eggs, and die within a few weeks. (Photo: CNN)
Unlike other insects, such as crickets, which produce sound by rubbing their wings together, male cicadas create sound by vibrating two “timbales” made of thin membranes that develop from their thorax, equipped with internal ribs. These ribs contract rapidly, causing the membranes to vibrate, producing sound waves. The cicada’s hollow abdomen amplifies the sound, resulting in a very loud call. Cicadas shake their bodies and use their wings to create the rhythm for their “song.” Each cicada species has a unique sound, intensity, and pitch – used to attract female cicadas of the same species.
Some cicada species can produce sounds up to 120 dB, making them one of the loudest insects.
4 Detrimental Effects of Large Cicada Populations in the U.S.
However, the simultaneous emergence of a large number of cicadas in the U.S. can cause several serious issues for the country.
- First, their noise is so loud that it can exceed the sound of airplanes, causing tremendous disruption.
- Second, these cicadas only live for about 4 to 6 weeks, dying on sidewalks and streets where they can be crushed by people or cars, making everything dirty and slippery.
The simultaneous emergence of a large number of cicadas can cause serious harm to the country. (Photo: CNN)
- Third, these cicadas will suck sap from trees, drilling holes everywhere to lay eggs, which can cause severe damage to trees and soil, amounting to millions of dollars.
- Fourth, birds that typically feed on leaf-eating caterpillars will switch to hunting cicadas. However, this will lead to an increase in caterpillar populations, which will also eat young leaves of trees and cause significant losses.
Do Cicadas Really Only Cause Harm Without Any Benefit?
According to entomology professor May Berenbaum from the University of Illinois, the truth is that humans are misjudging these insects. The emergence of cicadas is not as frightening as we think. Apart from the noise, cicadas do not bite, sting, or carry any diseases. Conversely, the holes they dig help aerate the soil, allowing rainwater to seep down and nourish tree roots.
The grooves they create on trees may cause branches to break, but this is akin to a natural pruning that helps the branches and fruits grow larger when they regrow.
In fact, the emergence of cicadas also brings some benefits. (Photo: CNN).
Furthermore, instead of cleaning up dead cicadas, humans can use them as natural fertilizer to provide nutrients for crops.
Therefore, the Environmental Protection Agency (EPA) and some scientists have urged Americans not to resort to extreme measures to kill cicadas. Instead, they should welcome this as a remarkable natural event that occurs only temporarily.
