Thinking about both the spectacle and the long waiting period, a cicada spawning season is a big deal in the midwestern and eastern United States. This year marks a distinct event: both a 17-year brood and a 13-year brood will emerge all at once. A “brood” is scientific term for a group of cicadas that emerge synchronously.
When this takes place, sometime around mid-May, a big number of cicadas will descend– and especially upon Illinois. The next double-tap cicada event wont happen up until 2037.
Periodical cicadas invest most of their lives underground as nymphs, just to emerge synchronously across vast locations after 13 or 17 years, depending upon the types. This long developmental phase, invested in the peaceful darkness below the soil, is a development period during which the nymphs feed on sap from tree roots.
A Brood X cicada. Credit: Katja Schulz/Flickr.
Male cicadas climb to the tree branches to sing in chorus, a call to draw in mates. After mating, female cicadas lay their eggs in tree branches, and, when the eggs hatch, the brand-new nymphs fall to the ground and burrow into the soil.
Cicadas undertake among the most amazing life cycles in the animal kingdom. Its timeline varies too. There are 2 kinds of cicadas: annual and periodical. While annual cicadas appear every year, its the periodical cicadas that are truly interesting.
The cicada double-whammy
Adult periodical cicadas typically measure about 1 to 1.5 inches (2.5 to 3.8 cm) in length. They possess a striking black body that supplies a stark contrast to their intense red eyes. They have transparent wings that have prominent veins and are held roof-like over their bodies when at rest.
These broods emerge in various years and in different geographical areas, frequently covering specific locations in the main and eastern United States. In time, scientists and nature lovers have thoroughly mapped the place and cycles of each brood, which is how we understand when and where a development will happen.
There are 15 identified broods of periodical cicadas in the United States. Of these, 12 are 17-year cicadas and 3 are 13-year cicadas.
Various periodical cicada broods in the U.S. and their respective areas. Credit: USDA.
The territory where the two broods coincide is not huge, which may be a great thing considering the interruption this might trigger. Because its so unusual to see two distinct populations of periodical cicadas emerge together, researchers are particularly thrilled. They will be particularly on the lookout for any interbreeding occasions and what might come out of it.
Map of double cicada brood emerging in 2024. Source: The Cidada Project at the University of Connecticut/The Washington Post.
The yearly cicada, left, and the periodical cicada, right. Credit: Tamra Reall.
The 13- and 17-year cicadas are various types, which explains their various periodicity. There are 9 types of periodical cicadas, 7 of which live in the United States, part of the genus Magicicada. There are a total of over 3,400 species of cicadas in the world, highlighting just how special the periodical variety can be.
This spring and early summer season, Brood XIX (called the Great Southern Brood) will emerge in Missouri, Arkansas, southern Illinois, Tennessee, Alabama, Georgia, the Carolinas, and surrounding states from its 13-year-old rest. Brood XIII, or the Northern Illinois Brood, will molt out of its 17-year cycle in Illinois, Iowa, and Wisconsin. The next co-emergence of these 2 particular breeds wont occur for another 13 x 17 years (221 years).
When this will take place is unsure, the exact timing of. When the insects are fully grown and the surrounding soil reaches 64 degrees Fahrenheit (17 degrees Celsius), the cicadas are excellent to go.
A song as loud as a jet engine
The system behind their ability to produce such powerful noises is a fascinating example of natures resourcefulness in style.
A skilled eye can identify in between the different types of cicadas. You dont have to be an entomologist to notice the difference between 2 different broods if you rely on your ears.
What the 17-year cicada sounds like individually and as a group. Credit: Live Free/YouTube.
While the possibility of trillions of cicadas generating out of thin air might sound menacing, theres no genuine cause for issue. They do not sting or bite. Theyre not insects and besides the sound (and the smell), theyre very little of a nuisance. Somethings for sure, birds enjoy them (for lunch).
The reason behind the specific 13- or 17-year cycles of periodical cicadas stays debatable. These prime numbers are believed to help avoid synchronization with the life cycles of potential predators, a technique that boosts their survival. When cicadas finally emerge, their integrated appearance in frustrating numbers guarantees that predators can not perhaps eat them all.
Besides birds, mammals, reptiles, and even some fish like to consume these bugs. When it comes to us humans, we can be content with the experience of their loud and magical phenomenon.
Male cicadas are equipped with a pair of specialized organs called tymbals, situated on the sides of the abdominal base. The tymbal is a ribbed membrane that the cicada can quickly contract and relax utilizing a muscle. This action causes the tymbal to buckle inwards and after that snap back to its initial position, developing a click sound with each buckle. When these clicks are produced rapidly in succession, they create the cicadas particular buzzing or singing sound. Cicadas are actually drawn to the vibrating sounds of power tools and lawnmowers, which resemble their tunes.
The abdominal area of the male cicada functions as a resonating chamber, magnifying the sound to levels that can exceed 100 decibels at a range of 20 inches (50 cm) away in some types, making cicadas among the loudest pests on the planet.
Idea they are known for their red eyes, cicada eyes really can be several colors, however not green. Credit: Gene Kritsky, Mount St. Joseph University.
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While annual cicadas appear every year, its the periodical cicadas that are truly appealing.
Scientists are especially delighted because its so uncommon to see 2 distinct populations of periodical cicadas emerge together.
There are 15 identified broods of periodical cicadas in the United States. Of these, 12 are 17-year cicadas and 3 are 13-year cicadas.
A “brood” is clinical term for a group of cicadas that emerge synchronously.