What if the zombie apocalypse didn’t come from a virus, but from crickets? Scientists have
recently uncovered how a mind controlling parasite infiltrates these insects, takes over their minds,
and drives them into harm's way. Could humans be the next host for this parasite?
Hairworms are the parasites that hijack crickets and force them to engage in suicidal behaviors.
The name itself is pretty disgusting, and rightfully so. Hairworms enter an unsuspecting
cricket as small larvae and then grow within the insect’s body. As the worm grows longer
and longer, it hijacks the cricket’s nervous system and forces the insect to do its bidding.
And if that wasn’t scary enough, one species of hairworm can grow up to 6 feet long.
The 6 foot species of hairworm infects much larger insects, or so scientists believe,
as they are not entirely sure what the hosts are for such large hairworms. For
right now we are pretty sure the hosts are not human, but who knows what the future may hold.
How does the hairworm infect and control its host? And should we
be worried about these parasites making humans their next target?
The scientific name for the cricket infecting hairworms is Paragordius
tricuspidatus. The main reason they have evolved to infect and control crickets is
to help them find water when it is scarce, so that they can reproduce. The parasites
can only mate in watery environments, and they cannot move very far on their own,
especially on land. The solution that hairworms have evolved is to exploit is wrapping their long,
slimy, bodies around the insides of crickets, and driving them to the closest water source.
Crickets tend to stay far away from water. They can easily drown, or worse,
be eaten by aquatic predators. So, in order to force crickets to travel to these dangerous areas,
the hairworm must take over the insect's body and mind. Crickets, like all living things, need water
to survive. Instead of obtaining it from dangerous rivers or ponds where they may get eaten,
crickets tend to acquire their H2O from dew drops, plants, and other smaller insects that they eat.
If the crickets consume something that has been infected with the hairworm larva it
is the beginning of the end for that insect. Hairworms lay their eggs in water. They sink
to the bottom and lie dormant until they are eaten by the larvae of other insects.
As these bugs grow, they carry the dormant parasite with them. The hairworm will not
hatch and grow in these insects, it will wait for a larger bug that it can control.
As the unknowing carrier of the parasite continues its life cycle they bring the
hairworm with them. Inevitably, some are eaten by unlucky crickets. When this
happens the hairworm larvae become active and all hell breaks loose.
Once a cricket swallows a hairworm larva a mysterious process begins. The worm hatches,
and makes its way out of the digestive system of the cricket and into the circulatory system,
where it can start mooching nutrients from its host to help it grow. The hairworm
doesn’t want to consume all of the crickets' nutrients, as it needs the host to be healthy
for when it takes over its mind later, and forces the cricket to do its bidding.
The hairworm lies in wait within the cricket and takes in nutrients directly through its
skin because it doesn’t have a mouth. It then grows, and grows, and grows,
snaking its way throughout the cricket's body and taking over essential areas.
This is where things get really weird, and why you should be worried about these nasty parasites.
There is no indication that a hairworm has taken over a cricket. This is a scary thought as an
infected cricket will act totally normal until the parasite is ready to reproduce,
and forces its host to engage in suicidal behavior. Once the hairworm finishes growing
inside of the cricket, it takes over the nervous system and makes a slight change
to the crickets behavior. The parasite forces the cricket to stop chirping.
This is probably because chirping can attract predators, and if the cricket host gets eaten,
the hairworm gets eaten along with it. Therefore, once the parasite has control,
it immediately turns off the chirping behavior to conserve energy and keep
its host from being eaten by a predator. As the parasite wraps itself around more
and more of the organs within the cricket it takes its mind controlling to the next level.
A regular cricket will stay far away from running water as it is biologically programmed
to know that water contains predators, and that it is not the best swimmer. However,
the parasite needs to reach water in order to reproduce, so it sends signals to the
cricket’s brain that convinces its host that water is exactly what the cricket needs,
and that there is no danger at all. However, nothing could be further from the truth.
Using the sensory systems of the cricket the hairworm forces it to seek out water.
It most likely does this by hijacking the antenna and retinal systems to steer the
cricket in the right direction. Scientists believe the hairworm
releases chemical signals that make light incredibly attractive to the crickets.
Since water tends to reflect the light from the moon, stars, and sun,
the cricket becomes attracted to the liquid. By forcing the cricket’s brain to move the host
towards the reflecting light, the hairworm is brought closer and closer to its goal.
The cricket is driven by its parasite to jump into the water. This is where things get really gross.
Once its host is in the water the hairworm needs to get out. It bores a hole in the
crickets exoskeleton and slides it's now foot long body out of the tiny insect. (use photo:
https://anamericanscientistiniceland.files.wordpress.com/2018/02/img_7687-2.jpg?w=676&h=852)
This must come as somewhat of a relief to the cricket as it slowly
regains control of its body. It also must be terrifying for the cricket as it wakes
up from a horrible nightmare only to find itself in a hostile environment.
The crazy thing is that crickets often survive the zombification process, and once the parasite
leaves their body, they can continue living the rest of their life normally. However,
since water is full of danger, not all crickets are so lucky.
It is also worth noting that although it’s normally only one hairworm per host, this
is not always the case. Sometimes a cricket can be infected with two or three worms (use photo:
https://pbs.twimg.com/media/C9oInauUQAEM-bd?format=jpg&name=small) . Once in the water all three will
spring out from inside the cricket and squirm their way into their new home. And if that
wasn’t gross enough, scientists have recorded a single cricket ejecting 32 worms from its body.
This host obviously didn’t survive this encounter as it was literally
torn apart from the inside as the hairworms wriggled their way out.
Once the parasite is done with its host it does not care whether the cricket survives or not.
Sometimes the cricket can make it out of the water alive, other times it can’t,
but the hairworm is done with the host now and has a new mission.
The hairworm swims around its new home looking for a mate to reproduce with.
If a male is lucky enough to find a female, it inseminates her, and its life is complete. The
sole purpose in life for a hairworm, as well as for many other organisms,
is to find a mate and reproduce. Once the male hairworm has mated it immediately dies. This
may seem unfortunate to us, but the hairworm has accomplished everything it needed to in its life.
The female continues on swimming and can lay approximately 15 million eggs,
which are secreted onto underwater pebbles, sticks, and other debris.
After she lays all of her eggs, the female hairworm dies as well.
About two weeks after the eggs are laid, and both parents are dead, the new batch of hairworm larvae
hatch and begin their journey to infect other crickets so the whole process can begin again.
At this point you are probably pretty grossed out, but it only gets worse.
You may be wondering how we know so much about hairworms and their hijacking of
crickets. It is because scientists have been studying them in their labs. We are
not saying that mad scientists are cooking up a mind controlling parasite that may lead to the
zombie apocalypse… but it is a crazy world we live in, so maybe we should be prepared just in case.
What scientists are actually doing is studying how exactly the hairworm parasite controls its
host. This is not the only parasite that hijacks a host's mind to do its bidding. For example, in the
Costa Rican jungles there is a wasp that lays its eggs within the abdomen of orb spiders. The larvae
begin to eat the spider from the inside, and when the wasp babies are strong enough, they release a
chemical that forces the spider to build a unique type of web that the wasp larvae will use to
build their cocoons in after they finish consuming their spider host. (use photo second from the top:
http://whiztimes.com/the-evil-wasp-that-rules-the-world/)
Some parasites like the lancet liver fluke flatworm infect multiple hosts. This parasite
first lives in the livers of grazing animals such as cows. Its eggs are eventually pooped out
where they wait patiently in the excrement for an unsuspecting snail to eat them.
The lancet liver fluke’s eggs then hatch inside of the snail and force it to create protective
cysts made of mucus for the larvae to live in, which the snail later excretes from its body.
The larvae contained in the protective mucus of the snail are then eaten by
ants. The parasite makes its way through the ants body and takes over their brain.
It forces the ant to climb to the top of a blade of grass and remain motionless
until it is consumed by a grazing animal so the whole process can start again.
These are just some of the many parasites that have scientists on edge. It is not out of the
realm of possibility that someday a parasite might evolve to infect and zombify humans.
The ability of one organism to gain control of another organism's mind
is a truly scary thought, but it is happening all of the time around the world.
This brings us back to what scientists have actually discovered about how the
hairworms control their cricket hosts. The worms seem to be producing large amounts
of neurotransmitters, which allow the parasite to trigger different
signals between the host’s brain cells. These neurotransmitters are most likely
what allows the hairworms to force crickets into doing what they want.
By understanding how hairworms control crickets, scientists have a better idea
of how other parasites control their hosts. This is not only important to understand for unlocking
the mysteries of the world around us, but this research could also become helpful in the future.
Especially if humans ever find themselves infected by a brain controlling parasite of our own.
It is important to remember that the mind controlling parasites of the
insect world evolved through natural processes. It took millions of years,
but the parasitic relationship that hairworms have exploited occurred through natural selection.
The benefits of understanding how the neurotransmitters secreted by parasites
like the hairworms actually influence a host's brain could lead to untold discoveries. It could
also save the human species from untold horrors, like zombification. For right now there are no
known parasites that can take over a human's brain and force them to do their will. But what about
in the future? The processes of evolution are always occurring, and it might not be
too long until one of these mind controlling parasites finds a way to exploit the human brain.
Then again, it is also very unlikely this would occur within our lifetime. But it is
always good to keep pushing our scientific understanding of the natural world forward,
so that we can be ready if the zombie apocalypse ever does occur due to mind controlling parasites.
Now watch “USA Military Actually Has A Zombie Plan - This Is It
(Conplan 8888).” Or check out “Most Painful Parasites That Infect Humans.”