With their bulging red eyes and alien-like mating sounds, periodical cicadas can appear both intimidating and peculiar. However, some of them undergo a transformation into hypersexual zombies, driven by a super-sized fungus.

West Virginia University mycology professor Matt Kasson, his 9-year-old son Oliver, and graduate student Angie Macias are investigating a notorious fungus known as Massospora cicadina. This is the only fungus on Earth known to produce amphetamine—commonly known as speed—within an organism once it takes over. The fungus hijacks the cicadas, inducing hypersexual behavior to facilitate the spread of the parasite as a sexually transmitted disease.

“They’re zombies, completely at the mercy of the fungus,” says University of Connecticut cicada researcher John Cooley.

This particular fungus boasts the largest known genome of any fungus, with about 1.5 billion base pairs, which is approximately 30 times larger than many common fungi, Kasson explains. When periodical cicadas reside underground for 17 years (or 13 years in the U.S. South), the spores typically remain dormant with them.

“This was a mycological oddity for a long time,” Kasson says. “It’s got the biggest genome. It produces wild compounds. It keeps the host active—all these quirks to it.”

Examining the Fungus

The needle-like ovipositor used for egg-laying remains visible. Kasson dissects fungal tissue from the posterior abdomen of a female periodical cicada infected with Massospora cicadina.

Despite an injured leg, Kasson, his son, and Macias traveled from West Virginia to the Morton Arboretum outside Chicago, where the fungus has been reported to take over a cicada’s reproductive organs, replacing them with a white, gummy yet flaky plug that is quite noticeable. The spores then fall out like salt from a shaker.

Infected cicadas are supposed to be challenging to find.

Ten seconds after she dismounts from the golf cart, Macias is in the trees, searching. She triumphantly raises a cicada, shouting, “I got one.”

“That was just luck,” Oliver complains.

“Luck, huh? Let’s see you get one,” Macias retorts.

Ten seconds later, Oliver discovers another cicada at a neighboring bush, and shortly thereafter, a photographer finds a third.

Kasson and his small team collected 36 infected cicadas during their brief visit to the Chicago area, with people sending him another 200 from various locations. He is still awaiting an RNA analysis of the fungus.

Prevalence and Spread

Some cicada experts estimate that perhaps one in 1,000 periodical cicadas are infected with this fungus, but this is speculative. Gene Kritsky, a biologist from Mount St. Joseph University who wrote a book on this year’s unique dual emergence, suggests the estimate might be skewed because healthy cicadas tend to stay higher up in the trees.

This year, “the fungus is about how it always is,” Cooley says via email. “It’s not super common.”

There is ongoing scientific debate about whether the fungus infects more cicadas deep in the soil before they emerge after 13 or 17 years, or if it infects the newly hatched nymphs on their way underground for more than a decade.

This fungus does not kill its host but rather needs it to remain alive. The infected cicadas attempt to mate with others, spreading the spores to their mates or victims. In their hypersexualized state, males even mimic females to entice and infect other males, Kasson explains.

Psychedelic Cousins

A related fungus that infects annual cicadas out west also produces psychoactive compounds, but these are more akin to psychedelics like magic mushrooms. Consequently, people, even experts, sometimes confuse the amphetamine produced by the infected 17- and 13-year cicadas with the more hallucinogenic compounds of the annual cicadas.

Regardless, it is advisable not to try consuming these infected cicadas. Though cicadas themselves are edible, the infected ones are not recommended.

In the name of science, Kasson sampled one during this emergence, ensuring it was from the inside of a female for better antiseptic properties.

“Man, it was so bitter,” Kasson recalls, describing how he immediately rinsed his mouth. “It tasted like something you would consider poisonous.”