Zombie ant fungus (Eccentric cordyceps ophiocordyceps unilateralis)
Ants are very professional navigators and the paths they use when looking for food are usually very efficient. But in the rainforests of Thailand, Africa and Brazil, the Leyzin ant is hijacked by a parasitic fungus called The eccentric Cordyceps sinensis (see image above).
When the spores infect ants that search for food in the rainforest, they spend 3 to 9 days growing in the host, and when the fungus is ready to complete its life cycle, it will turn its slaves into zombies and be controlled to leave the safe zone.
A 2009 study showed that the ant usually goes to the same destination, at 25 centimeters above the top of a tree, where the humidity is just right for the fungus to grow, and dies after biting the leaf with its jaw.
Within 24 hours, fungal filaments formed from the remains, and eventually the stalks broke out of the ant's shell and spread the spores again onto the rainforest floor to wait for more ants to infect. This scene is a bit like the image of an alien breaking its chest, except that the ant is dead when the fungus breaks its head.
A nematode swims out of the cricket's body.
<b>Nematodes (Nematode phylum Paragordius tricuspidatus</b>).
This type of parasite can grow as long as a foot and look like a cooked pasta. But to be fully mature, it needs to summon its servants—a cricket or grasshopper.
Initially, an insect larvae, such as a mosquito or ephemera, swallow very small linear larvae, and when they appear on the surface of the water and are preyed by crickets or grasshoppers, the nematodes begin to grow inside the crickets.
But the last step of the adult needs to be carried out in the water, but crickets generally do not swim, or do not even like to be near the water's edge, so nematodes need to find a way.
Nematodes force crickets to jump into nearby water by altering the function of the cricket's central nervous system. The unlucky crickets can only drown alive, and the nematodes break out of their bodies to breed.
From the outside, you can't tell if the crickets are infected or not, but on the nervous system the parasite has taken control of the host's body. Ben Hanelt, of the University of New Mexico in Albuquerque, specializes in parasites, mentioned that he had seen 32 parasites in an unfortunate host.
An ordinary coastal crab with egg pieces of the genus Crab on its body.
<b>Parasitic barnacles (crab slave Sacculina sp.).</b>
If you think it's great enough to make a cricket think they can swim, this parasitic barnacles will take the ability to seize control of the body to another level.
Crab slaves can enter the host crab through a crack in the claw joint, and it can shed its outer hard shell and squeeze itself into the crevice. At this point, it looked more like a bunch of slugs than the barnacles that usually stuck under the boat.
After settling in, it robs the crab of its nutrients and turns the host into a breeding tool. When the barnacles are fully grown, it looks more like a soft and pulsating egg yolk.
If the crab were a female, the crab slave would force it to help care for thousands of barnacles as if it were its own child. But if the crab is male, it will be femaleized to accomplish the same task, which includes not only taking away fertility, but also growing a larger lower abdomen to carry barnacles and stopping growing defensive crab claws.
An amber snail controlled by a green-banded cyst.
<b>Green-banded cysts (Double-disc fluke Leucochloridium paradoxum</b>).
If you find a snail with beautiful patterns on its eyes, decorated with emerald green and olive green stripes, dark gray spots, and a brown tip, don't be surprised. You're not just looking at a snail in costume, it's also a snail infected with parasitic flatworms.
First of all, green-banded cysts squeeze themselves into the tentacles of snails, so they look like very colorful and active caterpillars, which is a favorite snack of nearby birds.
The parasite then controls the snail's movements. In 2013, Wanda Wesolowska and Tomaz Weslowski of the University of Wrocław in Poland found that infected snails behaved significantly differently from other non-infected companions. They appear in more exposed and bright places, climbing higher up on the plant, which may be to make it easier for birds looking for food to spot snails.
When a host is swallowed by a bird, the parasite can multiply within and then continue to cycle through their life cycle.
Brown-spotted ladybirds carry a parasitic cocoon.
<b>Ladybird parasite (Ladybird cocoon bee Dilocampus coccinellae</b>).
Such wasps need a host to protect their eggs from predators. So what bodyguard could be more useful than an insect with a deadly warning?
Ladybugs look a bit like cartoon dolls and cute bento boxes, but they can protect themselves completely, releasing disgusting poisonous gas when infested, and their hard shells have bright red and black spots to warn predators of their danger. However, they are completely powerless to face parasitic bees, leaving an egg with each stab.
When the eggs hatch, the larvae will gnaw through a hole in the ladybird's internal organs, then break through its lower abdomen and spit out a cocoon between its legs. By this time, ladybugs have become a "bodyguard" to protect the cocoon. Still alive, it flaps and shakes its legs to drive away predators if a predator approaches. It's unclear why it behaves this way, and it could also be caused by venom reserved by the larvae.
Even more surprising is the fact that a quarter of zombie ladybugs found in a 2011 study were alive during the infestation.
A flat-headed mud bee crawls out of the body of an American cockroach.
Ampulex compressa
The flat-headed mud bee has a metallic lustrous skin and emeralds on its feet. Usually found in the tropics of Asia, Africa and the Pacific islands, it looks beautiful, but unfortunately the cockroach collided with it.
It's about a sixth the size of a cockroach, but that doesn't stop it from moving. First, it stung and paralyzed the cockroach, then injected neurotransmitters into the cockroach's brain to hijack its thoughts. In this way, the cockroach becomes an isolated zombie.
After quickly sucking the cockroach's blood dry, the flat-headed mud bee bit off its tentacles and was controlled back into its nest like a dog with a collar. There, it lays eggs on the cockroach's abdomen and uses stones to block its escape. But the hapless cockroach didn't even try to escape, even though it could physically do it. It just sits there obediently, and then the larvae nibble it alive. Finally, the grown flat-headed mud bee bursts out of the cockroach's body.
Toxoplasma gondii
<b>Toxoplasma</b> <b>gondii (Toxoplasma gondii).</b>
This single-celled organism is the most famous of all the parasites that control host behavior, probably because it is so close to our lives. It usually infects mice and rats, which are then eaten by cats and bred in the body.
A 2007 study showed that infected mice forget their fear of cat odor. Instead, they are attracted to pheromones in the cat's urine. As a result, these infected animals do not choose to hide themselves under the floor anymore, preferring to appear in front of their feline predators, allowing the parasite to find its ultimate goal: the cat's stomach.
About 30 to 60 percent of humans are infected with toxoplasmosis, but it's unclear whether the parasite also affects human behavior. In 2006, Kevin Lafferty of the U.S. Geological Survey in Santa Barbara, California, found partial evidence of personality changes in humans infected with toxoplasmosis. So far, these are just some related points, and there are still no correct conclusions. But, Lafferty says, "I'm more concerned about its causation." ”
Toxoplasma gondii is also common in schizophrenic patients, but here we are not quite sure whether that means this is its effect. "Schizophrenia is a very complex syndrome that can be caused by a variety of factors." Lafferty said. He stressed that many people infected with Toxoplasma gondii are also not schizophrenic, and that many of the patients with schizophrenia are not infected with Toxoplasma gondii. "So, I can definitively say that Toxoplasma gondii is just one of the associated factors in schizophrenia."
The rabies virus escapes from the host.
<b>Rabies virus</b>
You might think that something like the rabies virus shouldn't be counted as a parasite, but as a biologist, it does belong to the parasite class. "I would call rabies and flu viruses parasites because they harm the health of the host or sacrifice the host for self-interest." Levi Morran of Emory University in Atlanta, Georgia, said.
The rabies virus is a very frightening parasite because it seems to blur the boundaries between humans and animals. The virus can be transmitted through saliva and usually occurs after scratching or biting. It makes animals — usually dogs and bats, and sometimes humans — more aggressive, forcing them to spread the virus by scratching and biting.
"The rabies virus can control a very wide range of different nerve signals, including changing behavior habits and even losing motor control." Andres Gomez of ICF International Consulting in Washington, D.C. said. "After that, it can sometimes lead to dysphagia leading to starvation, hypoglycemia and dehydration."
It has been speculated that it will cause the host to develop a sense of water phobia, but this is still a mystery. "Patients twitch involuntarily when they want to drink water or see it afterwards." Gomez said: "But it's not fear. ”
H1N1 influenza virus
<b>influenza virus</b>
Yes, it's the flu. In 2010, Chris Reiber and her colleagues at Binghamton University in New York City found evidence that the flu virus made people more socially friendly.
They found that people who received the flu vaccine interacted significantly after 48 hours with more people and larger groups than they did 48 hours earlier. Infected hosts are more likely to go clubbing and partying.
It's just one of those studies, and it's the smallest one, but it always feels very sinister. These methods should be very beneficial to the virus because it will expose the host to more humans as much as possible before symptoms appear and the host falls ill.
Three-spined fish infected with taenia schizocephalus.
<b>Schistocephalus solidus</b>
We are surrounded by parasites. Most races live longer than a parasite, and the parasite has its own unique parasites. In some cases, there will be parasites with different purposes in a host that need to compete to control host behavior. This is especially true when one of the parasites is ready to move to another host and the other is not.
To observe this, Nina Hafer of the Max Planck Institute for Evolutionary Biology in Plen County, Germany, infected a small crustacean called the copepod (the white sword flea) with a variety of tapeworms (taenias). These tapeworms eventually need to move to a fish host called the three-spined fish, and in order to achieve this they will control the behavior of the copepod, making it more active and easier to be seen and swallowed by the three-spined fish.
If both tapeworms are ready to move to a new host at the same time, their influence on the behavior of the copepods will be stronger, and it can be seen that they are working together.
However, if the old tapeworm wants to leave, but it shares the same host with another young tapeworm, and the other person is not ready, the copepod host will also come alive, as if the young tapeworm does not exist.
Hafer and Milinski have been debating whether the tapeworms really suppress the younger contenders.