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Billions of Insects: The Brood X Cicada Swarm
Brood X (also known as Brood 10; the X is the Roman numeral for “10”) is a brood of periodical cicadas that emerges every 17 years in the eastern United States. A “brood,” in this case, means billions of the large, buzzing insects all emerging at the same time. They crawl out of the ground over the course of a week or two to form an unforgettable swarm.
This article tells you what you need to know about the cicadas of Brood X, as well as the other 15 broods that will one day crawl out of the ground to create their own swarms.
Quick Facts About Cicadas
- Cicadas cannot bite, sting, or hurt you in any way
- Cicadas do not typically damage trees or plants
- Cicadas spend over 10 years underground, and then they crawl out and hatch into the winged adult
- Cicadas “sing” by vibrating part of their body called a “tympanum.” The song is meant to attract a mate
- By hatching out all at once, Brood X cicadas overwhelm predators by sheer numbers. This means enough will reproduce to continue the species.
Where Will Brood X Cicadas Show Up?
The below map shows a good idea of where and when each of the periodical cicada broods will emerge. Brood X is in yellow. The actual range of the insects may be larger than illustrated.
What Are Cicadas?
Cicadas are insects with six legs and wings; they fly well, but cannot crawl or move very quickly. Most people never see the immature form of this insect; they spend their time – anywhere from 14 to 17 years – underground, sucking plant juices from tree roots. When it’s time to transform into the winged adult cicada, it crawls to the surface.
Complete Versus Incomplete Metamorphosis
The process of changing is known as “metamorphosis.” "Complete metamorphosis" is the term used to describe the life cycle of insects that go through a four-stage sequence of forms. For butterflies, this means egg-larva-cocoon/chrysalis-adult. It helps to take the butterfly as the example, although bees, wasps, flies, beetles, and many other insects also go through complete metamorphosis. Like butterflies, they all have larvae and all of the other developmental stages.
Cicadas are typical of the insects that undergo incomplete metamorphosis, which means they skip the pupa stage. The egg is laid on twigs, and the tiny larva hatches out and drops to the ground. From there they burrow underground, and stay there for years. When they finally crawl out, as Brood X will do in spring 2021, they are about the size of your thumb. They crawl up a tree or the side of a nearby building, where they adult hatches out. The shell they leave behind is a familiar site to anyone who has spent some time outside in the summer.
The Cicada's Unique Song
Once the adult cicada has hatched out and its wings have unfurled and hardened, it flies away to find a mate. One of a cicada’s most noticeable qualities is the penetrating sound that they make. For some people, a buzzing cicada is a pleasant part of a summer day; for others, it sounds annoyingly like a dentist’s drill. For another cicada, it sounds like a sweet, seductive call, and allows the insects to find each other in order to mate.
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Issues Caused by a Brood X Emergence
Brood X is known as one of the largest of the 15 broods. It amounts to literally billions of individual insects. They are harmless, but there are several drawbacks to having that many insects out and about all at the same time. In some areas, a cicada hatch results in insects coating roads and sidewalks, to the point where they can be dangerously slippery from crushed insects. When the cicadas all die, after a week or two, the stench of rotting insects can be sickening.
The Cicadas' Natural Enemies
Cicadas are eaten by almost every predator possible, from birds to cats. But one of the most interesting is a huge wasp called a “cicada killer.” This wasp can be seen patrolling in the late summer, looking for the “dog day” cicadas that emerge every July in the eastern part of the United States. Cicada killer wasps catch a live cicada, sting it to immobilize it, and bring it back to the nest, a burrow in the ground. The female wasp stuffs the cicada into the burrow, lays an egg on it, and leaves. The wasp larva eats the cicada as it develops.
This, by the way, is basically the same process by which a tarantula hawk wasp preys on tarantula spiders.
Are Cicadas Locusts?
The quick answer is “no.” A locust is a kind of grasshopper that often occurs in swarms in parts of Africa and the Mideast. A cicada is in the same group as aphids. They are both insects, but they are not closely related.
Brood X: What Should You Do?
The emergence of Brood X cicadas is a spectacular and rare event. By all means take pictures, make videos, and record what you see and experience. You may be moved to write poetry or music, or make art that reflects on this natural wonder. Also, of course, you should drive carefully, and get ready to shovel the insects off your sidewalks. Remember that cicadas are completely harmless, and after the swarm is over they will go back underground to wait for another 17 years. Where will you be in 17 years?
The following sources were used for this guide:
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on April 26, 2021:
In 17 years time, I'll be 81. I like the simple way you tell and write the article. The information is educative. Thanks for the read