We often see such a scene in some horror films, where humans are infected by the virus and turn into zombies, like the walking dead, they are completely reduced to the tools of virus transmission.
In fact, such scenarios are very common in nature.
This is a picture taken by scientists, and the snail's eyes are constantly flashing like neon lights in a barbershop.
What makes the snail's eyes keep flashing is a parasite that parasitizes in the snail's body, and its purpose is to expose the snail to itself, and then be eaten by the bird to achieve the purpose of entering the bird's body to hatch.
<h1 class="pgc-h-arrow-right" data-track="179" > how does this parasite manipulate snails? </h1>
The scientific community has known about the parasite for more than a century.
It wasn't until 2013 that Polish biologists tracked and recorded the worm and finally confirmed that the worm could actually manipulate the snail, making it its first host.
Snails are only intermediate hosts for this parasite, and birds are their main hosts. How do you get yourself from the snail's body into the bird's body? Sometimes you have to admit that the species intelligence of nature is beyond your imagination.
This parasite is called diplodocus, scientific name Leucochloridium paradoxum, belonging to the genus Heterodipans in the family Bilocarpidae of the order Phylum Pyrophyllaceae.
They live in wet places, such as swamps, where they are usually inhabited by intermediate host snails. When the snail eats the bird droppings with the eggs, the worms will complete a series of preparations in the snail's body.
Wait, why do snails eat bird droppings with eggs?
In fact, this is an infinite dead loop designed by the parasite throughout its life cycle.
The parasite is eaten by snails, snails are eaten by birds, birds excrete worm eggs, and are eaten by snails, snails are eaten by birds...
The snail eats the eggs only to complete the first step of the long march, and the second step is that the parasite grows in the snail's body and begins to really manipulate.
Absorb nutrients and enjoy them
The eggs that are eaten by the snail develop into the next stage in the snail's liver and pancreas, the sporangia. They are constantly growing, and the nutrients needed for growth do not rely on their own efforts at all, as long as they stay at home, they can absorb the hard-earned nutrients of snails through the skin.
Castrate the snail – I sucked your blood and skinned you
Snails are hermaphrodite animals.
But in order to ensure that they can get enough energy, parasites also castrate snails, because the production of eggs and sperm consumes too much energy from snails, and parasites must ensure that this energy can only be used by themselves.
Manipulate the snail's eyes
The mature sporangia growing in the snail's body consist of many branches that will spread through the blood cells, some of which will pass through the snail's body and into the snail's eye stalk (also known as the antennae), where a brood sac filled with larvae forms.
Why does the parasite choose to invade a snail's eye and manipulate its eyes? This is the precise first step in the evolution of the parasite.
Normally there is an immature eye spot at the tip of the snail's antennae, which can only distinguish light from darkness. Snails can't see the color, and the eye handle doesn't have the muscles needed to focus. However, snails can retract the muscles of the antennae.
When the parasite invades, the snail's antennae are greatly inflated and cannot be retracted. Pulsating, colored, banded larvae are visible throughout the antennae.
As the larvae dance the disco inside, the worm-eyed snail looks like a giant caterpillar.
This is a nutritious and delicious protein meal for birds.
In biology, this behavior of parasites is known as aggressive imitation, in which one organism pretends to be another in order to lure prey to eat itself.
Manipulate the activity of the snail
After disguising themselves as caterpillars, a new problem arises, with snails essentially nocturnal, while most of the birds that prey on sight are active during the day. How do these two species meet?
Once the parasite is fully developed in the snail's eye handle, it begins to manipulate the snail's behavior, forcing it to go outside during the day, where predators flock to it.
How can the parasite accomplish this incredible maneuvering? This remains a mystery. Scientists speculate that it is possible that the bugs used some kind of chemical.
But what's even stranger is how do parasites that live in snails distinguish between day and night? Bugs don't have any sensory organs or nervous systems that can sense light, but they only beat during the day and never at night. It's very, very unusual, and no one knows how it's achieved.
In addition, biologists have found that infected snails are very active.
And these snails will stay in more exposed places under the control of insects, such as above plants or higher places. The purpose of all this is to be spotted by the birds, so that the hungry birds can gouge out their eyes and eat them.
In the internal organs of birds, they develop into adult worms, about 1.5 mm long. Adults are hermaphrodites, they reproduce, and then release their eggs through bird droppings, which are happily eaten by snails, thus completing its entire strange life cycle.
Do you think that's the end of it at this point? Wrong, it's not over yet. The bugs also kept a hand.
Birds will tear the snail's tentacles and eye sockets off the snail before eating it, so the snail will not die, they will continue to survive, and their lost antennae and eye sockets will regenerate.
In this way, the snail that was once parasitic will eventually become another potential host, which is quite beneficial to these parasites. Because I can recycle you indefinitely.
<h1 class="pgc-h-arrow-right" data-track="245" > summary</h1>
This worm shows in a rather creepy way how diverse and opportunistic the parasites in the animal kingdom are. They use a series of means to manipulate snails to achieve their own ends.
If you believe me, more than half of all living things on Earth are parasitic in some way.