Lice are one of the most hated pests in humans.
Once hair and clothing are accidentally invaded, they will parasitize the human body at the right time.
The redness and itching on the skin is their victory.
In addition to humans, some of its "relatives" will also poison other animals.
Some may live permanently directly attached to the epidermis, and some may even bite their tongues to replace them...
The infamous lice, though only the size of an ant, are no less suspicious.
It is an insect that usually parasitizes only birds, humans, and other mammals.
It sucks blood from humans and can also spread unexpected viruses and bacteria.
There are several creatures also known as "lice", which, although they also live by parasitism, have very different ways of getting along with their hosts.
head louse
If you accidentally lose a hand in an accident, the prosthesis is a substitute for maintaining daily operations.
A creature called the shrunken-headed fish lice gave a false tongue to a fish that had lost its tongue.
It is held in the mouth as a living "prosthesis" for the life of a fish lice.
But it is not simply out of kindness and selfless dedication.
On the contrary, it is the murderer who bites off his tongue in an attempt to take his place.
The name of the shrunken-headed fish lice can easily cause misunderstandings about its properties.
In fact, it only survives through parasitic relationships like lice, not lice.
Looking for relatives and asking the ancestors, its relationship with shrimp and crabs is closer.
They are crustaceans with hard shells and sharp claws.
However, the shrunken-headed fish lice have only a tiny body of 3 to 4 centimeters.
Although its body is petite, its hands are unambiguous, and even some of them are "fierce".
After all, in order to survive, you can only exert the greatest potential strength.
By virtue of its size, it cleverly slips into the body of the fish through the gills of the fish.
The thick tongue of the fish appeared like a prey.
A shrunken-headed fish lice that enter from the gills
Subsequently, it hooks its tongue with its sharp front paws.
Then use the strong hind legs to fix yourself behind the tongue.
The tongue of the fish has also been firmly controlled by it.
At this time, the fish lice, which occupies an excellent position, looks like a victor.
And the real murderous scene has just been unveiled.
Fish lice punctures a blood vessel on the tongue of its future host with a powerful bite.
After the incision is formed, it begins to suck blood.
Both to fill the stomach and to get the tongue out as soon as possible.
The bleeding tongue quickly atrophied and eventually fell off.
After a series of flowing movements, this vicious fight without suspense is over.
The successful invasion of the shrunken-headed fish lice finally succeeded in replacing the tongue.
Although the life after the host has lost its freedom, food and clothing are no longer a problem.
It is the only way for all food to eat, and naturally it will not miss the opportunity to scaveng for debris.
And when the host really can't find food, its "tongue" even falls into the well, sucking its blood and mucus and other substances.
But of course, it doesn't cause too much damage to the host.
After all, this is the shelter on which it will survive for the rest of its life, and it no longer wants to taste the taste of "sleeping on the street".
The weird parasitism is not enough to show the legendary life of the shrunken-headed fish lice.
As a hermaphrodite species, its transgender process is also jaw-dropping.
Juvenile fish lice are present as males.
After the completion of development, it is regulated by hormones, and a gender transition occurs.
The female shows the fierce face of becoming a tongue lice, which is the scene of the invasion.
Shrunken-headed fish lice develop at different stages
In the long "lice" life, the shrunken-headed fish lice have other important things to do in addition to eating, such as mating.
However, it must also be loyal and stick to the position of "tongue".
As a result, the male fish lice from afar had to resort to some strategy.
They gradually approached the gill chamber and slipped into the mouth of the host of the "standing guard" lice to complete this sacred mating.
I don't know how much psychological shadow this has caused to the poor host.
In fact, humans also parasitize a large number of bacteria and other tiny organisms.
Maybe they're also somehow carrying out everyday life that we're unaware of.
Fortunately, parasites the size of the shrunken-headed fish lice are fairly rare.
So there was no such panicked feeling of fear and nausea.
The shrunken-headed fish lice mostly parasitize seabream and 7 other similar species.
The small size of the body is easy to make people feel weird.
Some of the much smaller parasitic lice are keen on the huge cetaceans.
Hence the name whale lice, they contain more than 30 species.
Whale lice are also crustaceans and look somewhat similar to shrimp.
The body length is only 5 to 25 mm, and it is not easy to be detected even if it is densely glued to the giant whale.
In resource-scarce oceans, the whale's epidermis is equivalent to a fertile organic substrate.
Therefore, many tiny parasites come to try to get a piece of the pie.
Among them is the figure of whale lice, and one whale often gathers 7500 huge whale lice families.
In addition to this, barnacles are also regulars on them.
These small, light-colored creatures attached to the surface of the whale also become a unique marker on the whale.
Large patches announce the victory of the parasites' invasion.
Whale lice with barnacles overgrown whale backs
Whales are the overlords of the ocean, known for their large size and fierceness.
For the small creatures on its body, it can be described as a sense of security.
So they began to enjoy the feeling of riding a whale-skin "speedboat" in the ocean.
However, the strong currents brought about by the excessive speed do not make it easy for these passengers to stand firm.
Therefore, with limited grip, they can only choose baleen whales, humpback whales, gray whales and other slower species.
In order to catch up with the ferocious giant whale, the whale lice naturally have special skills.
Among the limited body structures, the hook-like end structure and sharp mouth pliers are among the few practical tools.
They rely on sharp claws to cling to the whale's epidermis.
It is also a "yacht" with no destination.
A brief schematic diagram of the structure of the whale lice
But in terms of adhesion, whale lice are still no better than barnacles with unique structures.
Therefore, it is only condescending to the second seat, hiding in the epidermis of skin wounds, head and abdominal folds, kisses or nostrils.
In order to fix themselves to the host skin as much as possible, whale lice also do everything they can.
They do not hesitate to bite off the skin of the host, thus embedding themselves deeply.
Whale lice at the folds
And the bitten skin is not wasted, and it directly becomes their food ingested into the body.
Of course, such a large group cannot blindly exploit the host.
From a sustainability perspective, they have to find another food.
Yet a life of uncertainty is destined not to allow them to stop.
As a result, plankton are their main food source.
Some plankton
The waves in the sea are turbulent, and the tiny whale lice have no swimming skills.
They can then only be transmitted through contact with the skin of the host.
There are not many such opportunities, and getting engaged and migrating is a daunting task.
Therefore, a whale is usually the lifelong fate of the whale lice.
Parasitism is often associated with bad outcomes such as death and illness.
In the broad biological world, the relationship between animals and animals is not necessarily bound to degenerate into a fierce struggle between life and death.
In the not-so-fair competition of species, there may be a relatively kind way of getting along.
*References
Cymothoa exigua. Wikipedia.
Whale louse. Wikipedia.
Jolene Creighton. Cymothoa Exigua: Meet theSex-Changing, Tongue-Eating Parasite. Futurism. 2014.
Elizabeth Preston. The Lonely Lives of DolphinLice. The Atlantic. 2017.
Secrets of the Whale Riders. News Center.The University of UTAH.
Fengfeixue0219. Whale lice, barnacles, and the "micro-world" carried by giant whales. Nutshell. 2015.01.22.