How Cicada Fungus Makes the Bugs Try and Mate Like Crazy So It Can Spread

As periodical cicadas emerge from the ground across the eastern U.S., some might be infected by a bizarre parasitic fungus that hijacks the brains of the insects, manipulating them so that they try and mate like crazy.

Periodical cicadas are seven species from the genus Magicicada that emerge from the ground every 13 or 17 years in North America. The cicadas that will burst from the ground in 2021 are referred to as "Brood X."

These cicadas spend most of their lives underground as nymphs, but when the 13- or 17-year period is over—depending on the species—the insects crawl out of the soil and molt, transforming into their adult phase. During this phase of their life, the cicadas mate and lay eggs.

Out of the billions and billions of cicadas that will rise up out of the ground, only a small percentage will be infected with the psychoactive fungus, Massospora cicadina, which contains one of the same active ingredients as magic mushrooms—psilocybin.

"The fungus lies dormant in the soil until the cicada comes up," Matt Kasson, an associate professor of forest pathology and mycology at West Virginia University, told The Guardian. "It recognizes a hormonal signal from the cicada itself."

Normally, male periodical cicadas attract females by producing loud buzzing sounds. In response, the females flick their wings in a particular way.

But Massospora causes infected males to become hyperactive while significantly increasing their sex drive, leading them to try and mate with anything they can find—including other males.

In fact, the fungus manipulates the males into flicking their wings like females—a display that other males see as an invitation to mate.

This tempts unsuspecting males to approach the infected cicadas, thus, increasing the chances that the fungus has to jump from one insect to another, according to a study published in the journal PLOS Pathogens last year.

Brian Lovett, a co-author of the study from West Virginia University, said in a press release accompanying the study: "Essentially, the cicadas are luring others into becoming infected because their healthy counterparts are interested in mating."

"The bioactive compounds may manipulate the insect to stay awake and continue to transmit the pathogen for longer," he said.

The fungus has horrific consequences for infected cicadas, devouring the insects' genitals and lower abdomen. In their place grows a fungal mass that shoots out spores capable of infecting other individuals.

Unfortunately for the infected cicadas, the loss of their genitals means that despite their increased sex drive, they are unable to successfully mate with any individuals.

"Funguses in the genus Massospora affect many different species of cicadas, but Massospora cicadina is specialized to the periodical cicada genus Magicicada," Elizabeth Barnes, an entomologist at Purdue University in West Lafayette, Indiana, told Live Science.

"This species of fungus is actually the only pathogen or predator that specializes on periodical cicadas. Its life cycle lines up pretty neatly to the cicadas. Most of the time in the insect world, any given species of insect will have many organisms that specialize on eating or infecting them. It's very unusual for a whole genus of insect to only have one."

A periodical cicada
A periodical Brood X cicada climbs up an oak tree in Washington, D.C. on May 20, 2021. Some cicadas will be infected with a parasitic fungus known as Massospora cicadina. MANDEL NGAN/AFP via Getty Images