Zombies are all around us—insect zombies, that is. Zombifying parasites reproduce by infecting victims and rewriting their neurochemistry, transforming them into the walking dead. Ants, crickets, caterpillars, and other hosts helplessly follow a zombifier’s commands, living only to serve the parasite’s needs until death’s sweet release (and often beyond).
“Rise of the Zombie Bugs” explores the eerie yet fascinating phenomenon of real-life zombification in insects and other invertebrates. Zombification is one of nature’s most unsettling survival strategies, with zombifiers evolving over millions of years to become deft neuroscientists capable of reprogramming host behavior. Victims of their manipulation are found worldwide—from Brazilian rainforests to European meadows.
Why is a bug’s world full of zombies, and could parasites that zombify invertebrates evolve to do the same to people? “Rise of the Zombie Bugs” offers a chilling yet enlightening look at the hidden world of mind-controlling parasites. It’s a must-read for anyone curious about the true terrors lurking in nature’s undergrowth and the unnerving beauty of evolution’s darker side.
Parasitic worms turn snails into disco-eyed zombies.
Have you ever seen a zombified snail, its swollen eyestalks pulsing in a mesmerizing display of patterns and colors? Researching Zombie Bugs introduced me to parasitic flatworms in the genus Leucochloridium; when these worms infect a snail, they produce larvae-stuffed broodsacs that grow inside the snail’s body. Sausage-shaped and striped in shades of green and brown, the broodsacs migrate into the snail’s eyestalks. When they vigorously undulate there, they look like creeping caterpillars.
Leucochloridium hatches and matures in snails, but reproduces in birds. In addition to making caterpillar-like broodsacs, the parasites manipulate snail behavior so that the snails wander out in the open, where they’re more likely to be spotted by predators. When a bird pecks off an infected snail’s eyestalk and swallows the broodsac, the worms end up exactly where they need to be in order to reproduce—inside a bird’s gut.
In fact, lots of behavior-manipulating parasites cause wandering or light-seeking behavior in their hosts (hey, remember those fungal-infected sleepwalkers in Wanderers?), particularly during the late stages of infection. Zombifying fungi, worms, flies and viruses all benefit from their hosts’ walking, hopping or crawling under their own power, to find a spot that’s ideal for the parasite’s reproduction.
“Find Familiar” is an excellent D&D spell and very good writing advice.
One of my favorite wizard spells in D&D—”Find Familiar”—also turned out to be helpful guidance for writing a popular science book. When I started researching Zombie Bugs, much of the science was not familiar to me. So I read dozens of scientific papers. I spoke with entomologists, mycologists and parasitologists. I visited museum collections. I organized chapters based on who was doing the zombifying and how.
It was a lot to sort and process! I wanted to start the book with the origins of zombification, how it works, and what studying zombie bugs reveals about human brains and behaviors. But the scope of those questions felt overwhelming, and I couldn’t find an entry point for that first chapter.
So I set it aside and started a different chapter, about something that was more familiar to me: fungus-infected zombie cicadas. The fungus Massospora cicadina grows inside adult periodical cicadas, until their butts fall off to reveal a yellow plug of tightly-packed spores. Massospora also doses its hosts with a type of amphetamine that causes hypersexualized behavior, so they spread zombification like an STD. I actually found one of these drug-addled zombies in Princeton, New Jersey, during the Brood X periodical cicada emergence of 2018, and being personally acquainted with zombie cicadas made me more confident about diving into that chapter.
Re-creating the scene from that day in Princeton—the spring sunshine, the crunch of cicada exoskeletons underfoot, the surprise and thrill of finding my first zombie—was a joy to write. And once I had that under my belt, finding my way into the next chapter (and the one after that) was so much easier.
If you kick really hard, you can avoid being zombified.
Cockroaches are survivors. Still, it surprised me to find out that they have a special strategy for surviving zombifying attacks by jewel wasps. Female wasps sting roaches in the head, delivering a venomous cocktail that makes the roach as docile as a puppy. The wasp then leads its stung, passive roach to her nest. She walls it up inside with a hungry wasp larva, and the roach ends its life as a Happy Meal.
But unlike most insect victims of zombification, roaches often fight back and defeat their zombifiers! Researchers at Vanderbilt University’s Catania Lab captured high-speed footage showing that roaches defended themselves against zombifying wasp attacks with vigorous kicks. In about 63% of such attacks, the roaches escaped unscathed (unless they weren’t fully grown, in which case the wasps were able to zombify the roach youngsters 100% of the time).
Zombies? The CDC had a plan for that.
More than a decade before HBO’s The Last of Us introduced TV audiences to the Infected —zombies created by a fictional variant of the zombie ant fungus Ophiocordyceps—AMC’s The Walking Dead captivated viewers with its more traditional decaying zombies, created by an unspecified virus. Much to my delight, I discovered that the success of The Walking Dead inspired the U.S. Centers for Disease Control and Prevention to launch a “Zombie Preparedness” campaign in 2011, which I was able to track down online because the internet is amazing. (Seriously, go look this up. There were posters! There’s a downloadable comic!) Obviously, the CDC wasn’t hinting at an imminent zombie apocalypse; they were using zombies as a way to get people to think about pandemics and disaster preparedness. At the time, CDC director Dr. Ali Khan wrote, “If you are generally well equipped to deal with a zombie apocalypse you will be prepared for a hurricane, pandemic, earthquake, or terrorist attack.” When the CDC launched this campaign, it was so popular that it temporarily crashed the agency’s website (they finally retired their Zombie Preparedness materials in 2021).
Since then, researchers have created mathematical models of hypothetical zombie outbreaks to study the spread of infectious diseases. Healthcare workers in hospitals and with the Red Cross train for high-pressure medical emergency scenarios by treating “patients” during staged zombie attacks. There’s even a scientific conference called the Zombie Apocalypse Medicine Meeting, where experts from different disciplines meet to talk about a range of science topics related to zombification. The pervasiveness of zombies in pop culture has some unexpectedly practical real-world applications for science, medicine and public health!
A deep dive into Alien‘s backstory led to a gut-wrenching discovery.
If you’ve seen the movie Alien, the chestburster scene is probably seared into your brain. As soon as I learned about the original chestbursters—wasp larvae that hatch and grow inside zombified caterpillars, then chew through their host’s skin and pupate inside cocoons on the caterpillars’ backs—I knew that they deserved their own chapter in Zombie Bugs.
I’d heard rumors that the Alien filmmakers based their chestburster on these parasitic wasps, but though I combed through interviews, I couldn’t track down a solid connection. What I did discover was that Alien screenwriter Dan O’Bannon found inspiration for the chestburster from his own experience with Crohn’s disease, a gastrointestinal disorder that causes excruciating gut pain. It has no cure, and it eventually caused O’Bannon’s death in 2009.
While I was researching O’Bannon, I found something else that stuck with me: a scan of a sketch that he made before production began, of the xenomorph’s larval facehugger stage. His illustration wasn’t as terrifying as the film’s facehugger; the drawing, which looked like an angry cartoon crab, was actually kind of cute. As a writer working on her first book, I found reassurance in that derpy concept art, knowing that it would eventually transform into something unforgettably horrific. It reminded me that first drafts of anything don’t need to be perfect. They just need to be done.
Mindy Weisberger is a science writer and editor at Scholastic, Inc. and has written about science for CNN, Scientific American, Live Science and Space.com. Her writing covers parasites, new species discoveries, weird animal behavior, strange medical cases, paleontology, climate change, archaeology and space exploration. For more than a decade, Weisberger produced, wrote and directed media for the American Museum of Natural History, and she scripted and co-hosted the science podcast Life’s Little Mysteries. She lives on a cliff in New Jersey with her husband, two cats, and too many ukuleles.
Mindy Weisberger: Website | Bluesky
Rise of the Zombie Bugs: Bookshop | Indiebound | B&N | Amazon
Dave Williams says:
This is a creepy and fascinating topic. Years ago, my family and I were on a road trip and listening to Radiolab. In this particular episode, Carl Zimmer — author of “Parasite Rex” — was the guest. Zimmer’s stories of parasites blew our minds (in a good way). That episode stayed with me, and I eventually grouped it with a comment that I used to teasingly ask my daughters while they were reading: “Have you gotten to the part about the zombie butler at the pool party yet?” Those two items grew into my novel “Bugbies,” in which parasitoid wasps turn people zombie-ish. Writing that book was a wild ride. Anyway, detour over. Congratulations to Mindy on her book!
April 17, 2025 — 4:37 PM