This STI Makes Crickets Horny Before Killing Them

The virus IIV-6/CrIV up close. Photo courtesy Don Stoltz

A Canadian researcher has found a new sexually transmitted infection on the scene that uses mind control to spread to as many unsuspecting victims as possible before turning their guts blue and killing them. Luckily, the highly contagious and resilient virus has only been found to affect crickets.

Shelley Adamo, a researcher at Dalhousie University, says she accidentally found the virus—officially dubbed IIV-6/CrIV—while conducting an unrelated experiment with bearded dragon reptiles and some of the crickets from her lab colony. Not long after the experiment, what Adamo says looked like perfectly healthy female crickets stopped laying eggs. So she sliced one open to figure out what was going on.

“When I opened her up, I was shocked, because usually females are packed with eggs,” Adamo says. “These females had no eggs. Instead, they were packed with fat tissue. Not only that, the fat tissue looked a little odd. It had this iridescent blue sheen to it, so I knew something was really wrong.”

It’s natural for animals, including us, to want to hunker down when we’re sick. Food and fun lose all appeal, but it’s not the sickness telling our bodies to be lame. It’s our immune system telling us to chill out and get some much-needed rest. The fact that these very sick crickets showed no sign of losing their appetites or energy is what got Adamo curious.

What she and her team found was a strain of something called iridovirus, known for its ability to turn bug innards different colors. She took the lead on a report called “A viral aphrodisiac in the cricket Gryllus texensis,” which shows how the virus uses the crickets’ courting rituals to spread.

Here’s how cricket lovemaking usually works: In the wild, a guy cricket will start rubbing his wings together around dusk to create a sound that draws in the ladies. (This part of the process is done artificially in Adamo’s lab by putting the crickets in a breeding bin together.) If a lady cricket walks his way, the two insects will feel each other up with their antennae. “They have chemical receptors in their antennae, so they’re sort of tasting each other to see if they’re the right species and good mates for each other,” Adamo says.

Once the antennae foreplay wraps up, the male cricket will start singing a different tune for the female called the courtship song. This is the part where he’s trying to get the lady cricket to mount him. If she decides to hop on, Adamo says the guy cricket will give her “a little pouch of sperm.”

In Adamo’s experiments, the infected male lab crickets were much quicker to start singing the courtship song than the healthy males. In fact, it took the sick crickets only about three minutes to start singing their sexy tune, as opposed to the ten minutes it took the healthy guys to heat things up. “It was quite a striking difference,” she says. However, she says she doesn’t know how the virus manages to do this.

According to the report, the virus spreads through the heavy petting that goes on before and during coitus. Adamo says she suspects that like other iridoviridae, the virus gets in to the crickets through their mouths.

Once inside, the virus shuts down the immune system and the cricket-equivalent of white blood cells, offering no outside signs that anything’s wrong. Adamo says she and her team even tried to inject the infected crickets with bacteria that would normally slow down their appetites. “They just kept eating,” she says.

That’s why the virus is so contagious, she says. Not only do the crickets not lose energy, but they want to bang even more, which spreads the virus to other unsuspecting partners.

So how did her quarantined, healthy lab colony get infected? Adamo says one of the bearded dragons was carrying the virus, which it got from the mass-bred commercial crickets it eats on the regular, and gave it to her crickets while in close contact.

The virus was so successful at spreading throughout her colony of about 2,000 to 4,000 crickets that not only did it kill all of them, but it also tainted the plastic and glass walls of the lab containers. She and her team spent weeks bleaching everything in the lab. “It was quite traumatic,” she says.

In a lab, the virus can spread in many ways. Crickets are kept in close quarters where they can bump into each other easily and contract the virus. Cricket cannibalism is also to blame, she says. These circumstances don’t really exist in the wild, because the type of Texan cricket Adamo studies doesn’t like to socialize, nor do hungry predators give them much chance to chow on their friends’ dead bodies. The only instance where this kind of cricket comes into intimate contact is during lovemaking, so that’s why Adamo says the virus is sexually transmitted.

David Hughes, a biologist at Penn State University, says Adamo’s findings are surprising because her strain of the virus sterilizes the female victims. “There are a lot of reasons why you’re not going to see such an evolutionary route, that’s why Adamo’s paper is so remarkable,” he says. Normally, you would think that a virus that makes its victims have lots of sex would also want to pass on the infection to offspring.

Hughes is most well known for his discovery of the zombie-ant phenomenon. He also served as a consultant for World War Z, a 2013 blockbuster about a planet overrun with a zombie-like infection, and a video game called The Last of Us.

More than half of life on Earth is parasitic, but Hughes says only a few parasites and viruses have evolved to the point of mind manipulation—and mammals aren’t immune. Hughes says toxoplasmosis in rats, or “fatal feline attraction,” makes the rat attracted to its predator. “They go towards the cat, the cat eats the rat, and the parasite gets to where it wants to be, which is inside the body of the cat, the only place it can reproduce,” Hughes says.

He says we shouldn’t be worried about a new STI that takes control of our libido, though. Viruses and parasites can evolve to jump to humans, but won’t bring mind control along, as is the case with rabies. “It’s not going to sweep through and cause a zombie apocalypse,” Hughes says.

Bug brains and human brains are too different for viruses—even if they manage to evolve to jump the species barrier—to work in the same way on us. “They have perfectly evolved to fit their chemical keys into whatever lock they happen to be in. That key just won’t work in a different lock,” he says. “But [bug-borne viruses] still have the potential to kill us.”

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