James Smith
As if lying dormant in the earth for 17 years wasn’t strange enough, cicadas have another bizarre habit: they urinate like crazy, at up to 3 meters per second. The news comes while they are preparing to emerge in the Chicago areaone of the most populous areas of the this year’s cicada map.
A study credited to two authors from the Georgia Institute of Technology – titled “Unifying fluid excretion across the lifespan, from cicadas to elephants” – postulates that cicadas weighing just a few grams “possess the ability to eject fluids through remarkably small orifices.”
Scientists who study these things have discovered that cicadas urinate because they consume an incredible volume of liquid during their brief time above ground.
How much do cicadas pee?
In their study, M. Saad Bhamla and Elio Challita write that cicadas have a unique digestive system that allows them to process tree sap fluid 300 times their body weight.
Other insects that feed in a similar way urinate in droplets. Cicadas, on the other hand, are voracious eaters, consuming large amounts of nutrient-poor “xylem sap.”
“This jet capacity allows efficient processing of their nutritionally scarce diet of xylem sap and places them as the smallest animals known to form high-velocity jets in a regime dominated by surface tension,” the authors wrote.
And it’s not easy to get into the xylem, which doesn’t flow only when an insect enters it because it’s under negative pressure. The cicada can get the fluid because its outsized head has a pump, said Carrie Deans, an entomologist at the University of Alabama in Huntsville.
They use their trunk like a tiny straw — about the width of a strand of hair — with the pump sucking up the liquid, said Saad Bhamla, a professor of biophysics at Georgia Tech. They spend almost their entire lives drinking, year after year.
“It’s a tough way to make a living,” Deans said.
Be prepared to get a little wet
Researchers said cicadas are known to use their stream of pee to spray intruders. People have reported being hit by the urine of the small insects.
In the study, cicadas were clearly the queens, urinating two to three times harder and faster than elephants and humans. He couldn’t look at the periodical cicadas that feed and urinate mainly underground, but he used video to record and measure the flow rate of their Amazonian cousins, which reached about 3 meters per second.
They have a muscle that pushes waste through a small hole like a jet, Bhamla said. He said he learned this when, in the Amazon, he found a tree that locals called the “crying tree” because liquid oozed out, as if the plant was crying. It was cicada pee.
“You walk through a forest where they are actively singing on a hot, sunny day. It looks like it’s raining,” said University of Connecticut entomologist John Cooley. This is the honeydew or residue that comes out at the end… It’s called cicada rain.
So, as billions of cicadas emerge in Illinois, be prepared to get a little wet.
Where will cicadas emerge in 2024?
Two broods of cicadas are emerging at the same time this year, meaning the U.S. will see more cicadas than usual. The main litters are Litter XIXwhich comes out every 13 years, and Litter XIII, which comes out every 17 years. Both broods are expected to hatch in various locations across Illinois this cycle.
As they are temperature dependent, their appearance may vary depending on the location. In 2024, they are expected in May or early June, according to Ken Johnson, a horticulture educator at the University of Illinois.
After hatching, cicadas generally live only for a certain period of weeks. They spend most of their time reproducing.
