Hosts, also known as hosts, generally refer to those organisms that provide nutrients and living environment for parasites, including parasites and viruses. Most parasites will parasitize in the host's body to take nutrients directly from the host's flesh, and some parasites will control the host's brain, making them more obedient to the parasite's instructions, forcing the host to involuntarily do some dangerous behaviors. Parasites often damage the host, making the host sick or even dead, and some parasites can develop peacefully with the host or even coexist in harmony, but this situation is rare.
Nature is cruel, some hosts are parasitized, until death do not know that their fate has long been predestined, they spend their whole lives for their own growth, but later they cheapen the parasites on the body, but this is the survival law of nature - survival of the fittest.
Of the parasites known to control the host's brain, Toxoplasma gondii is the most famous. It is a single-celled protozoa commonly known as Toxoplasma gondii. The parasite is widely parasitic in human and a variety of animal nucleated cells and is an important opportunistic pathogenic toxoplasmosis that can occur when the host's resistance is insufficient.
Toxoplasma gondii is very complex in development, and a toxoplasma gondii needs at least two hosts to grow and reproduce, and they reproduce asexually and sexually in the bodies of these two hosts, respectively. Toxoplasma gondii can perform asexual reproduction and sexual reproduction in felines, so cats are the ultimate host and intermediate host of Toxoplasma gondii, and toxoplasma gondii can only be carried out in humans or other animals for asexual reproduction, so humans and many other animals are their intermediate hosts.
If Toxoplasma gondii enters mice or mice, they will change the behavior of the mouse, making the host very interested in items or areas that can emit cat odors such as cat urine, and the price of this crazy behavior is that the mouse is eaten by the cat, and then the toxoplasma gondii in the mouse will infect the cat, and toxoplasma gondii will breed more parasites in the cat. Toxoplasma gondii also lays eggs through the cat's intestinal wall into the cat's feces and excretes them, waiting for more hosts to infect.
In fact, this parasite is not terrible, uncooked meat, unhygienic food or water contaminated by cat feces will spread this parasite, most of the time, in the human body this parasite is in a harmless state, now there are perfect medical means to cure it, some media claims that it will control human emotions and behavior is unfounded.
And why the feline will become the ultimate host of Toxoplasma gondii, researchers found that the cat has a special fatty acid - linoleic acid, this nutrient is the key to the development of Toxoplasma to sexual reproduction, researchers in the asexual reproduction of toxoplasma petri dish, injected a small amount of linoleic acid, unexpectedly happened, Toxoplasma gondii can be sexual reproduction. So stop wronging felines, they are also victims.
After talking about Toxoplasma gondii, let's look at the ladybird cocoon bee that can directly control the host and make the host willing to protect its offspring.
Ladybird Cocoon Bee is a parasitic wasp of the genus Cocoon Bee of the subfamily Cocoon Bee family , which prefers to lay eggs in ladybirds , with a body of only about 4 mm , a yellowish brown on the top of its head and abdomen , and dark brown to black eyes , body , and limbs. If you are a little unfamiliar with the cocoon bee family, the cocoon bee family is a branch of the general family of bees, and we are very familiar with what the bees of the family are doing.
The biggest feature of the ladybird cocoon bee is that the ladybird cocoon bee larvae can manipulate the ladybird to protect the bee cocoon, which is indeed a bit excessive, the adult worm lays eggs in the ladybird body, and the larvae absorb nutrients in the ladybird body and break out of the abdomen, and will also manipulate the ladybug to hold the cocoon until the adult insect breaks out of the cocoon. Ladybird cocoon bee larvae can spend the winter in ladybirds, or they can spend the winter in the field with cocoons until the following spring in March and April, when they feather into adult insects, and the common hosts of ladybird cocoon bees are seven-star calves and rice red ladybirds.
Ladybird cocoon bees after determining the target, will use bee venom to paralyze the host, lay an egg in the ladybird body, the hatched larvae only swallow some fat, the development time of the larvae is very short, it only takes a few days, the larva bites a small hole in the ladybird's abdomen, and then the larva will weave a cocoon between the ladybird legs, and during the transformation of the entire larvae, the ladybird's body will stay on the top of the cocoon.
Since ladybird cocoon bee larvae do not harm vital organs in the ladybird's body, about 30% to 40% of the ladybird hosts survive after the ladybird cocoon bee larvae hatch, and some of these individuals can continue to lay eggs. Studies have shown that this behavior of ladybirds is related to the venom left in the body of ladybirds by larvae.
The length of time this control varies, and normally, ladybugs remain vigilant until the larvae break out of their cocoons and metamorphose into bees, and in other cases, ladybugs are controlled for a few days. Researchers have found an interesting phenomenon in these larvae, spending more time and energy to control the host's larvae, and laying fewer eggs in adulthood, which is the first time scientists have found a trade-off between controlling the host and their own reproduction.
Obviously, the parasitic behavior of ladybird cocoon bees still requires skill, but most members of the general family of ji bees do not have such a mind to play tricks, most parasitic bees directly lay one to hundreds of eggs in the caterpillar body, crazy larvae will develop synchronously in the caterpillar body, and when the caterpillar thinks that the nutrients are ready to pupate, their task is completed, at this time the larvae will eat the caterpillar, in their body or drill out of the cocoon to pupate.
It seems to be cruel to the caterpillars, but there are about 7,000 species in the family Ji Bee in China, with a wide range of distribution, they are the natural enemies of crop pests, and have important biological control significance for the control of diseases and insect pests.