LBL Wildlife Report: Brood X Cicadas
It's a plane! It's an ambulance! It's aliens! No, it's the Brood X cicadas emerging after 17 years underground. In the next LBL Wildlife Report, Woodlands Nature Station lead naturalist John Pollpeter speaks with Tracy Ross about these loud, singing insects.
Part of the mystery surrounding Brood X cicadas is due to its sci-fi-esque name. The brood's name is properly pronounced 'brood ten.' "It's a Roman numeral," Pollpeter explains. "We don't know if they're going to come to our area, but they're definitely going to be in the Ohio Valley and part of the Tennessee Valley this year. The 17-year cicada. There's about 12 different broods out there in the eastern United States, and [Brood X] is one of the largest ones. It's centrally located in the Cincinnati area."
Millions of cicadas are expected to emerge throughout the Ohio and Tennessee valleys, but Pollpeter says that scientists are concerned these numbers are actually dwindling. "There are several broods, particularly in the northeastern United States, that scientists are very concerned about becoming extinct. Deforestation, climate change...some of those larger impacts have definitely reduced the amount of numbers. There have been a couple broods that have actually gone extinct," Pollpeter says.
The cicadas' stunning quantities is a survival strategy, Pollpeter explains. "It's an ecological term called predator satiation. You try to overwhelm the predators by just being large numbers. You're going to have sacrifices. A lot of them are going to be lost. But there's going to be a point where those predators are just so full of cicadas, that the other ones are going to be able to breed and create those large numbers of eggs and young that will, 17 years later, bring more."
A common cicada misconception is that these red-eyed insects are responsible for the biblical-like plagues in Africa and the Middle East. "Locusts are technically grasshoppers," Pollpeter says. Cicadas are more closely related to other hemipterans (half-winged) sucking insects like aphids and leafhoppers. The only similarity between grasshoppers and cicadas, Pollpeter explains, is their historically large quantities.
Not all cicadas live underground for long periods of time before emerging. Annual cicadas, nicknamed "dog days cicadas," pop up around July and August. These annual cicadas are harder to find. Unlike brood cicadas' satiation strategy, Pollpeter says annual cicadas' strategy is "to eat, breed, and hide from predators." The broods' strategy likely came about approximately 300,000 years ago in the glacial age to help the insects avoid long cold spells deep below the frost line.
"When the periodic cicadas come out for the next five weeks in the Tennessee and Ohio valleys, they're going to sing," Pollpeter says. "You're going to see the males come out first; after about five days of emerging, they're going to start singing. The decibel level is the equivalent to an ambulance siren. That's how loud they can be. They'll sing to attract the females, then the females will lay eggs on the new growth of trees. If you have old trees in your yard, you have nothing to worry about."
"If you planted a new apple or maple tree this year," he continues, "you might have some difficulty. It might do some damage to the trees. [Females] lay about 500 eggs. Those eggs then hatch, and they drop to the ground. They go into the ground about 12" below the frost line, and they'll attach to a tree root. They get the sap out of there...xylem tissue is what they tap into. Every time that tree leafs out and goes through that normal yearly cycle, that's how [cicadas] time what 17 years is. After 17 times of the tree leafing out, they will emerge and go through the cycle again."
Cicadas aren't just occasional noisy neighbors; they're a significant source of protein. "In other parts of the world, people do make regular food out of them." Other animals that wouldn't normally eat insects or meat, like squirrels, birds, fish, turtles, and snakes, also partake in these protein-packed bugs.
"Obviously, if you do try [to eat cicadas], make sure you read up on it. I think there's some good websites out there. From what I understand--I've never partaken myself--you want to get them when they're kind of soft, that whitish-green color, just hatching out as an adult. As they get a little older, they're a little bit more papery. The males are hollow because they make that loud sound, so they might not be as tasty to eat."
"When you look at some of the different records and stuff, we don't know if Brood X occurred in Murray. It could've been one of the other 12 broods, maybe even the 13-year ones," Pollpeter says. "But it's something that might be neat to travel for just to see the large numbers."
Pollpeter invites citizen scientists to help keep records of this year's brood by downloading an app called Cicada Safari. "If you happen to notice the cicadas are popping up, you can take a picture, upload it to this app, and it will tell you what kind [of cicada] it is. You can do a recording of the sound because there are several different species of cicadas." This helps scientists more accurately map this year's cicada brood, which will, in turn, help with conservation efforts of this incredibly unique species.