“What a wonderful world,” sang Louis Armstrong back in 1967. Back in those simpler times, with just the horrors of the Cold War and possible imminent nuclear annihilation to be wary of, you could understand that naive enthusiasm.
However, the more scientists discover about nature, the more you realise how stomach-turning it can be. The idea that nature is 100% beautiful is hollow propaganda, and there’s no better proof than the following parasites and organisms that elegantly, but disgustingly, take control of their hosts to make them do their bidding.
The
toxoplasma gondii parasite is a well-known example. It’s so well-known that pregnant women are advised not to change cat litter. How does it end up there? Once consumed by mice and rats, it mutes their sense of fear, leading them to actively seek out cats and their own deaths at the paws and jaws of your cold-hearted fuzzy assassin. A side-effect is that it can affect human brains, though the effects are considerably more subtle.But more on T Gondii later. There are plenty of organisms that have some kind of mind-control powers, and probably plenty more we haven’t identified. Here are six fascinating examples…
The wasp that turns ladybirds into zombie bodyguards
The Dinocampus coccinellae manages to combine two of our least favourite words into one horrible species: “parasitic wasp”. Worse still, it picks on innocent ladybirds.
Targeted ladybirds are injected with the D. coccinellae virus, which attacks the ladybird’s nervous system, paralysing it with occasional spasms to give the illusion of a living, sentient creature. In this paralysed state, the unwitting ladybird protects the wasp larvae from predators.
Upon hatching, the infant wasps demonstrate their gratitude by feasting on their ladybird bodyguard. And yet, mysteriously, a third of ladybirds go on to make a full recovery – even the ones who’ve had bits eaten by their adopted wasp children.
The wasp that forces spiders to weave web coffins
The same can’t be said for the Plesiometa argyra – a Costa Rican spider that also falls victim to a parasitic wasp sting. This time, it’s the Hymenoepimecis argyraphaga wasp. It’s nature’s bully, as it seeks out a suitable spider target, paralyses it and lays an egg on its abdomen.
The spider awakens, blissfully unaware that it’s now literally eating for two, and goes about its merry arachnid business while the wasp larvae sucks its blood.
So far, so gross, but in a couple of sentences, you’ll look back on the last paragraph as a golden age of spider happiness. You see, after the wasp has drunk enough spider blood, it kicks things up a notch. It injects its spider host with a chemical that makes it want to build an unusual web – the one in the picture above.
The spider then goes and sits motionless in its unconventional web, waiting, as it turns out, for the sweet embrace of death. This comes soon enough, as the parasite poisons the spider, drinks its remaining blood and builds a cocoon in the super-strong spider web it subcontracted. Ugh
The nematode that disguises ants as delicious looking berries
As practical jokes go, this one is both ingenious and cruel. The nematode Myrmeconema neotropicum targets Cephalotes atratus ants, and literally gives them junk in the trunk.
The whole thing kicks off when an ant eats an infected bird dropping – so you could say it really only has itself to blame. Once consumed, the ant’s gaster turns red and swells to grotesque proportions, making the poor ants suddenly indistinguishable from berries to hungry birds. Sure, these berries seem to be moving, but doesn’t that just make them even more tempting? Birds love it when fruit plays hard to get.
To make absolutely sure the ants are eaten, infected ants are considerably slower than regular ones, and have the unfortunate habit of sticking their proud red rumps aloft. Sir Mixalot would be proud.
The hairworm that drives crickets to suicide
The Spinochordodes tellinii is a nematomorph hairworm. Adult hairworms spend their days as disgusting wriggling masses in bodies of water, copulating and creating larvae for the unsuspecting to drink.
Enter the cricket – which is precisely what the larvae does when the unsuspecting critter takes a sip of infected water. Now, remember that the Spinochordodes tellinii needs to return to a body of water to continue its debauched lifestyle? It releases mind-controlling chemicals into the cricket, forcing it to take a dip in a nearby lake, pond or stream.
It needs to do this because crickets can’t swim, so right-minded insects wouldn’t consider taking a dip. That’s right: the cricket drowns and the adult hairworms are released into the water to continue their path of cricket destruction. The hairworm literally drives crickets to suicide. Charming.
The tree that bribes its own private ant army
The acacia tree looks harmless enough, but it has an ingenious way of protecting itself against predators. It’s brought back military conscription to nearby ants.
Local ants love the acacia’s sugary nectar, and this works in the tree’s favour: the ants get incredibly aggressive when other creatures come along, warding off everything from spiders to giraffes with their massive army of footsoldiers.
You might assume this is a coincidence, but research from the University of London suggests the tree has evolved to manipulate its doting six-legged bodyguards. After all, if you need to pollinate, having an overzealous army attacking everything in sight is bad news. At this point, the tree spits out a chemical that’s physically repellent to the ants, driving them into a frenzy and making them back off.
Cleverly, the chemical is in the pollen, meaning that, as soon as it’s taken away, the ants can return unaware that they’ve just been outwitted by a tree.
The parasite that leads chimps to leopards
I said we’d return to T Gondii, and here we are. It’s well documented that mice lose their fear of cats and are drawn to cat urine when infected, but it turns out that this also affects chimpanzees, who are drawn to their only predator from the wild: the leopard. Researchers experimented on 33 captive chimps in Gabon, and found that those infected with T Gondii would be drawn to the urine of leopards, but crucially not to that of other big cats.
This might expain why the parasite seems to impact the human brain, albeit in a way that shouldn’t give T Gondii any satisfaction, given we humans are where the food chain ends.
Images: Yale Rosen, Wikimedia, Publy.ru, Steve Yanoviak, Wikimedia, Wikimedia, Florian Joussett.
Original publication by Alan Martin: Source article