by Caitlyn Johnstone
October 24, 2018
The most disturbing stories begin not on a dark and stormy night, but with the phrase: “it was a warm, sunny day in a flower garden.” While humans admire the smells and colors of spring, horrific scenes of torture, attack and hijacking may be taking place below. The most brutal tales of body snatching are not in the far corners of the exotic world, safely removed, but can be found right here at home in the Chesapeake.
Ladybug parasite (Dinocampus coccinellae)
Have you ever seen a ladybug holding a puffball? It isn’t nearly as innocent as it appears. The parasitic braconid wasp, Dinocampus coccinellae, turns a ladybug into a paralyzed incubator, food source and bodyguard.
The wasp inserts an egg into the vulnerable underbelly of the ladybug with a single sting. The wasp larva, in a safe and protected home, feasts on the ladybug’s insides.
Just about the time the larva is ready to hatch, it employs a neurological weapon: a virus. The virus was injected into the ladybug at the same time as the egg and while it grew, the virus did, too. The virus builds up in the brain cells, which burst open at about the same time that the wasp larva chews its way through the insides and bursts out the stomach of the ladybug.
Traumatically affected both physically and neurologically by bug and “bug” (the virus), the ladybug is paralyzed and merely twitches as the wasp larva spins a puffy cocoon on the belly of the ladybug. The ladybug then “guards” this puffy cocoon during its vulnerable stage; the ladybug’s bright red back and occasional twitching keep predators at bay. The adult wasp emerges from the cocoon about a week later.
Most of the ladybugs die from this enslavement encounter, understandably, though some are able to recover and survive. The quality of remaining life for the ladybug survivors or lasting effects from the experience are not well understood.
Braconid wasps (Braconidae)
Wasps are important biological controls, which means they keep in check the various caterpillars, worms, spiders and other insects that predate upon plants. If you’re a fan of herbs, lush gardens or fruits and vegetables, you should be a fan of wasps. The chilling factor comes in if you look too closely at just how wasps like the braconid keep a cap on caterpillars – brutally.
A braconid wasp will descend on a caterpillar–say, a hornworm snacking on a tomato– and slit into its soft caterpillar body. Along with her eggs, the female wasp injects the caterpillar with a virus, which shuts down the caterpillar’s ability to defend against these intruders. The wasp larvae deposited into the caterpillar body begin to grow beneath the surface, snacking on the caterpillar innards.
When they’re ready, the 80 or so larvae will chew out of the caterpillar’s body with their tiny razor teeth. Each little larva spins a cocoon, covering the caterpillar in little white puffy rice grains. The adult wasp will emerge from the cocoon by cutting a trapdoor cap into the cocoon, then flying off to seek out its own fresh host.
Emerald cockroach wasp (Ampulex compressa)
The American cockroach can withstand high doses of radiation, survive underwater for up to 30 minutes and can safely consume almost anything without detrimental effects. It has been on the earth since before the time of the dinosaurs and appears virtually indestructible.
Enter the emerald cockroach wasp: a beautiful, iridescent and macabre killer. Instead of spinning a soft home like other insects or finding a nice secluded log to house its young, the emerald wasp chooses as a nursery the body of a living cockroach.
Approaching the cockroach from the front, the wasp holds the roach’s head in both front legs the way one might console a loved one, then jabs its stinger into the roach’s brain. The injection disables the roach’s will to move independently, at which point the wasp takes the roach antennae in its mouth and leads it back like a dog on a leash to the wasp burrow. Controlled and docile, the roach sits passively while the wasp barricades it in with tiny pebbles after laying eggs in the roach’s stomach.
Paralyzed in its pebble cage, the roach is eaten alive from the inside by wasp larvae. Once they’ve eaten their fill and grown up in the cockroach’s body cavity, adult wasps burst from the (finally deceased) roach remains.
Protozoa parasite (Toxoplasma gondii)
This mind-altering parasite lives in the bodies of rats, mice and other rodents, but it can only reproduce in the digestive system of a cat. To make the leap from rat to cat, Toxoplasma gondii changes the behavior of the rodents by manipulating neurochemical pathways in their brains. They lose their sense of caution, lose their aversion to the scent of cat urine, venture further into the open and become reckless. Naturally, this behavior makes infected rodents far more likely to be caught and eaten by a cat, where the protozoa can begin reproducing.
As one of our favorite pets is the carrier for this little parasite, as much as 40 percent of the human population is also infected. The rate is 11 percent of the United States population, and as high as 60 percent in other areas of the world. The parasite causes the condition toxoplasmosis in humans, which usually causes a mild fever and eye irritation. While it is rare to manifest so severely, in infants it can cause severe eye and brain damage.
The real danger of toxoplasma is yet to be seen, as we are only just beginning to uncover the neurological effects. Recent studies have found that infected humans display the same risk-aversive behavior as rodents—they take riskier behaviors and are more gregarious, volatile and violent.
A recent paper in Biological Sciences shows that psychological disorders may run many of the same pathways as parasitic infections. People with high infection rates of toxoplasma are more likely to develop behavior disorders and to have children that eventually develop schizophrenia. A study in Denmark showed that even in those with no history of mental illness, women infected with toxoplasma were 56 percent more likely to commit self-directed violence. Those with the highest levels of antibodies (indicating a more severe infection) were 91 percent more likely to attempt suicide than uninfected women.
It is unclear whether it is the parasite itself, the body’s immune response or some other factor that is the direct cause of the behavior changes, but the relationship exists, making Toxoplasma gondii one of the scariest, and most versatile, of our backyard bodysnatchers.
Horsehair worm (Paragordius)
A horsehair worm begins its life harmlessly enough but grows to terrorize its host. Starting out as white strings of eggs in the water, horsehair worms hatch into free-swimming larvae and infect an aquatic host, such as a mosquito larva, within a few days. The worm larvae take the form of a cyst and the mosquito lives its life as an infected carrier until it is snapped up by a cricket. Though the mosquito dies in the encounter with the cricket, it may be the luckier of the two insects.
Now inside the body of the cricket, the larval cyst grows into an adult horsehair worm, where it takes up most of the cricket’s body. Penetrating through whatever is in the way, the horsehair worm grows into a thin, twisted creature that’s an average of a foot long. Now cramped for space, this aquatic adult worm needs to get to the water.
Crickets ordinarily have an aversion to water, but an infected cricket host is controlled by its worm parasite. The cricket will head in the direction of water by using its antennae to pick up changes in humidity, where it will proceed upon arrival to leap without hesitation to a watery death. The worm will then bore a hole in the drowned cricket, squiggle out into the water, and immediately seek out a mate.
Sometimes, nature can be cruel.