The Return of the Living Cicadas: Brood 10 to Emerge After 17 Years

The Return of the Living Cicadas: Brood 10 to Emerge After 17 Years

Seventeen is a big year. It’s a time of emergence after years of self-imposed isolation. No, we’re not talking about teenagers exiting the haze of adolescence. We’re referring to the cicada. Brood 10, a family of periodical cicadas, has been living underground for the last 17 years. With their lifecycle nearing its end, these insects will soon trade their subterranean world for our own.  

The emergence of Brood 10 is a biological phenomenon nearly two decades in the making. If the return of these dormant cicadas has you reading up on all manner of insects and arthropods, check out UF’s Entomology and Nematology Department for the latest on events, featured creatures and online programs.  

What to Expect When You’re Expecting Cicadas  

Heralded by warm rainfall, Brood 10 cicadas are expected to emerge around mid-May to late June 2021. (Cicada sightings were reported around May 13 in 2004.) That’s when the ground will thaw and reach temperatures around 64 degrees Fahrenheit, the ideal conditions for mating.  

Within days, the entire colony will surface, all 10 trillion of them. A single acre of land could give rise to over one million immature “nymph” cicadas. Emerging from their burrows, nymphs will climb the nearest vertical surface, usually the tree whose roots sustained them, and molt their shells to become adults. Empty larval cases will litter the ground like piles of leaves while their former occupants search for a mate.  

Adult Brood 10 cicadas are recognizable by their broad heads, black bodies and translucent orange wings. As reported by PBS NewsHour, “their red eyes were said to come from staring into the fires of Hades.” You may not have seen one before, but you’ve certainly heard them call to potential mates with their deafening “songs.” By vibrating membranes on their abdomens, male cicadas are able to sing in excess of 100 decibels — louder than a jet takeoff. (Click here to listen.) Females respond by flicking their wings to create a click similar to a finger snap.  

After mating, female cicadas will deposit their eggs in a slit in the bark of a tree. Newly hatched nymphs feed on sap from the arm of a tree. Eventually, the limb will break and send the nymphs plummeting to the ground below, where they will burrow and begin the process anew.  

The World’s Biggest Insect Emergence  

In 2004, Brood 10 amassed in such great numbers that witnesses reported that their sidewalks and yards were moving. If this year is similar, you can expect to see cicadas everywhere — on trees, fences and home exteriors. This is a rare chance to witness a natural wonder in America’s own backyard.  

Brood 10, or the Great Eastern Brood, is a massive colony spanning the Northeastern and Eastern regions of the United States. If you’re living in Washington D.C. or one of the 15 states listed below, you’ll have front row seats to the biggest insect emergence in the world: 

  • Delaware 
  • Georgia 
  • Illinois 
  • Indiana 
  • Kentucky 
  • Maryland 
  • Michigan 
  • New Jersey 
  • New York 
  • North Carolina 
  • Ohio 
  • Pennsylvania 
  • Tennessee 
  • Virginia 
  • West Virginia 

Trillions of winged insects rising from the earth seems like something out of the Old Testament, but don’t worry. Unlike locusts, which can cause major agricultural damage, cicadas are harmless. In fact, periodical cicadas have so few defenses that it may be the reason for their long, prime-numbered lifecycles, which prevent potential predators from developing lifecycles that are factors of that number. 

A Numbers Game 

It’s unclear why Brood 10 disappears for years on end. However, there is a prevailing theory: predator satiation. Cicadas are easy prey for a variety of animals, including birds, squirrels, dogs and cats. Clumsy and defenseless, periodical cicadas needed a way to ensure the survival of their species, even as countless of their kind succumbed to predators.  

In what has to be one of the most ingenious defenses in the animal kingdom, periodical cicadas display “predator foolhardy” behavior. Overwhelmed by sheer numbers, predators devour periodical cicadas until they are unable to feast on more. Trillions of Brood 10 cicadas become prey, but millions remain to successfully mate and perpetuate the species. This survival strategy has worked effectively for tens of thousands of years.  

Passing the Time 

Perhaps the most interesting fact about these cicadas is how they are able to track the passage of time. Buried in soil, away from light cues, Brood 10 nymphs spend their lives attached to tree roots. Here, they are able to measure seasonal pulses of nutrients and, in the process, count to 17. As incredible a feat as this may be, it’s just one of the countless evolutionary adaptations of insects.  

Become a Part of the Entomology Community  

This summer, you can join entomology professionals and enthusiasts across the country as they marvel at the emergence of these impressive, if clumsy, creatures. It’s a rare phenomenon that shouldn’t be missed (and probably can’t be avoided if you’re living in the East or Northeast). Of course, you don’t have to live in cicada territory to become a part of our entomological community.  

The University of Florida offers online master’s degree and graduate certificate programs that can help turn your passion for insects and arthropods into a rewarding career. Enroll in one of our online programs and learn how to solve arthropod-related problems from anywhere in the country, whether or not it’s in the heart of the Great Eastern Brood. Until then, we hope you’ll join us in keeping an eye on Brood 10 and their fleeting return to the land of the living. 


Learn More About the Program

Click for details about the Entomology and Nematology program.