Thirty-four years ago, I was a little kid out camping with my family and family friends when the 17-year cicadas emerged. One of my dad’s friends ate one. I was too young to remember, but I probably thought that was super cool. Now I live in Washington D.C., ground zero for this summer’s emergence of the Brood X cicadas; they were rolling so deep that they grounded a plane that was going to accompany the president overseas — by flooding the engines with their bodies — and began showing up as swarming masses on weather radar. This time, I’m positive I think they’re super cool, and, naturally, I was wondering if they’re ok to eat.
In chapter ten of Range, I wrote about research showing that science curiosity — not knowledge, but curiosity — was a predictor of people who did a good job evaluating new information, particularly when it didn’t comport with their pre-existing beliefs. So I try to use the world around me to spur my science curiosity.
With cicadas, I’ve been wondering what other species might have evolved to capitalize on their existence. Given that they hide away for so long, I figured if some other organism relies upon them for survival, that survival strategy would probably be utterly weird and totally captivating. On that count, I was right, but I didn’t expect the horror story I was in for. Friends, allow me to introduce you to the fungus known as Massospora cicadina — the world’s only known predator that is synchronized specifically to the life-cycle of 13- and 17-year cicadas.
Massospora make their living by — as the unusually lucid title of a scientific paper put it — “hijacking the sexual signals of periodical cicadas.” Here’s how it works: while the cicada is still underground waiting to emerge, the fungus infects it and starts growing, filling up the cicada’s abdomen, which in turn causes part of the abdomen to rot and crumble away. As the cicada’s rear end flakes off, the back of the cicada becomes just a big hole. Now the cicada starts flying around like a C-130 — except instead of sprinkling Navy SEALs out the back, it rains spores on unsuspecting fellow cicadas. (“Flying saltshakers of death,” in the words of one scientist.) We’re not at the crazy part yet….
The fungus now starts drugging its aforementioned flying saltshaker of death. It produces an amphetamine called cathinone, which is found in the leaves of the khat plant (humans chew those leaves to get a buzz), but that prior to Massospora was not known to occur outside of plants. It also produces psilocybin, of magic mushroom fame. That potent drug cocktail turns the cicada from just a run-of-the-mill flying saltshaker of death into a super-libidinous zombie flying saltshaker of death. As biologist Merlin Sheldrake puts it in his fascinating fungi book, Entangled Life, cicadas “become hyperactive and hypersexual despite the fact that their genitals have long since crumbled away.” (Never give up?)
The infected (and brainwashed) male and female cicadas proceed with their usual mating calls, and even those who have only half a crumbling abdomen left (bet they only put headshots on Tinder), will energetically try to mate with uninfected peers. And because one party in that endeavor has been hemorrhaging bodily structural integrity, the genitalia of infected cicadas will tend to break off and can be found stuck to the previously uninfected cicada.
The whole process of the fungus hijacking the cicada’s brain is fascinating. Once drugged, male cicadas demonstrate the wing-flicking courtship behavior normally seen in females, which in turn attracts more uninfected and unwitting suitors to come close and get infected.
Circling back to my initial curiosity about whether it’s ok to eat cicadas, I must say that learning about the mind-altering chemicals they might be buzzing around with gave me pause. Fortunately (or perhaps unfortunately if the psilocybin caught your interest), the dose that cicadas get is far below what would have any impact at all on a human. Thus, naturally, I’m now interested in how many infected cicadas (measured in multiples of plane-engine-clogging platoons) one would have to eat in order to either get high or turn into a hyperactive zombie. I hope someday to report back with an answer.
-Place bits of food as if they were cities on a map, and watch a fungus recreate the public transportation grid (but better). Given a map of Ikea, a slime mould was better at finding the exit than the scientists who created the experiment. So don't act surprised that slime moulds are being used to study disaster-evacuation routes.
-In groundbreaking work, Suzanne Simard showed that trees use networks of subterranean fungi to "talk" to one another, communicating needs and even trading food. Her research, and her struggle to get it recognized, are fictionalized in the 2019 Pulitzer Prize-winning novel, The Overstory.
-For more on parasitic brain control, check out Ed Yong’s enthralling TED Talk. (Ed recently won a Pulitzer for Covid reporting!) It includes one of my all time favorite jokes in a talk — the part that ends with “...a classic tale of Eat, Prey, Love.” Or if you just want to see what a famous chef can do with cicadas, check it out.
-Finally, Ed and I gave our TED Talks within minutes of one another. If you've gotten your daily fungal fix and are suffering from post-Olympics withdrawal, you might enjoy my first TED Talk on human athletic feats.
Thanks for reading. Until next week...