During the war in Afghanistan, the US military was well-equipped and had the upper hand on the battlefield, but once they were targeted by a group of difficult "dead soldiers", they had nothing to do, and no ** and no tactics could stop their attack.
It may come as a surprise that those "dead soldiers" were not sent by the enemy, but a group of naturally growing bed bugs. So much so that the U.S. military needs to send full-time insecticidal experts to the front line to "support".
In fact, bed bugs are not only difficult to get along with American soldiers, they will pestering any human if they have the chance.
Elusive bed bugs
Bed bugs are small insects that feed entirely on blood, which is commonly known as bed bugs and ticks. There are now about 90 species of bed bugs in the world, and they are only 1 to 7 millimeters in size.
Whether in a humid or dry environment, bed bugs can live leisurely. They are hidden in human clothing and luggage and spread around the world. And in the space where humans live, their favorite hiding places are the gaps between sofas and beds, cracks in walls, and even hidden places such as sockets and laptops. This makes them difficult to detect and difficult to eliminate them all.
Bed bugs are not only good at hiding, but also very hungry, most bed bugs can go three to five days without food at a time, and some can survive even a year without eating. Because they "don't happen" very often, some people don't realize that they are the ones who have been sucked by bed bugs, and they don't know that their homes have long been occupied by "invaders".
In addition, bed bugs are super fertile. It is estimated that a female bed bug can lay up to 5 eggs a day, or about 500 eggs in her lifetime. According to research, bed bugs are almost always inbred. In general, animals are inbreeding for multiple generations, and the offspring they give birth to will have physiological defects and a reduced chance of survival. But rather than affecting the physical condition of the bedbug's offspring, inbreeding has allowed the population to flourish, and scientists are not yet clear how they have this ability.
Humanity's war with bed bugs
If the bed bug is just an ordinary insect on the earth, it is just an ordinary insect on earth, but it has a constant relationship with humans. The war between humans and bed bugs has been going on for almost the entire history of human civilization.
Humans hate and fear bed bugs, not only because they are veritable vampires, but also because of the physical and mental torture they inflict on people. Wounds bitten by bed bugs can become swollen and itchy, and some people experience severe allergic reactions as a result. If there are a large number of bed bugs living in the house, then people may also suffer from insomnia due to frequent bed bug bites, and then feel irritable and anxious, and some people may even commit suicide because they can't bear the "harassment" of bed bugs.
In order to get rid of or kill these annoying creatures, humans have tried many methods, but they are not effective. In 1939, Swiss chemist Paul Hermann Müller discovered that DDT, a compound synthesized in the 70s of the 19th century, was effective against bed bugs. After that, this insecticide was widely used by people. Under the strong suppression of DDT, a large number of bed bugs were killed, and the surviving bed bugs lost the ability to make waves and fell silent for a while.
By the 70s of the 20th century, DDT was banned because it was harmful to humans and other mammals. Without the threat of DDT, coupled with the increasing prevalence of human travel, bed bugs have been frequently infested in some developed countries and regions such as Europe, North America, Australia and Asia in the past decade. They are not picky about the environment, not only breeding in slums with poor sanitation, but also making their homes in glossy high-end apartments and high-end office buildings, and New York City, the world-class metropolis in the United States, ranked second among the cities with the worst bed bugs in the United States in 2019.
In order to eradicate bed bugs, in recent years, scientists have studied the genes of bed bugs, hoping to find the "weak spots" of bed bugs and defeat them.
At the beginning of 2019, American scientists studied the genes of bed bugs and found that only after bed bugs have sucked blood for the first time, their exoskeletons will become thicker and harder, they will become less sensitive to toxins, and the speed of excretion of toxins will also become faster. This means that it is easier to kill the nymphs of bed bugs. In addition, scientists have also found that bed bugs have a large number of microorganisms on their bodies, and these microorganisms contribute to the survival of bed bugs. This means that if we attack these microorganisms, we may cause harm to bed bugs and thus destroy them.
Evolving vampires
The reason why humans have not been able to defeat bed bugs in the long war is not only because they are good at hiding and reproducing quickly, but also because of the ability of this annoying little thing to "improvise".
Recently, scientists have discovered that bed bugs have appeared as early as 11.5 billion years ago, it was a creature from the age of dinosaurs. While it's not known for sure if dinosaurs were their hosts, it's certain that they had changed hosts many times before humans appeared.
Another new study shows that a new bed bug has switched to feeding on human blood about every 500,000 years since the advent of humans. This means that bed bugs are highly adaptable, as it is not easy for them to change hosts. Bed bugs find their hosts based on clues such as smell, body temperature, etc. If they want to switch hosts, then they need to learn to confirm the information of the new host. What's more, each bed bug has a different digestive system, which allows them to digest the blood of a specific host. If the host is changed, then they need to change their digestive system, because different animals have different blood components and red blood cell sizes. In order to cope with the "trouble" of changing hosts, some bed bugs have directly evolved a "versatile" digestive system, such as the esophagus is more elastic, contractile, and relaxing, so that they can flexibly change hosts without going through a long evolution.
Bed bugs not only evolve to adapt to changes in their hosts, but they also evolve to improve their defenses and skills to deal with danger. American entomologist Dini Miller compared bed bugs before and after DDT was banned, and she found that after the massive use of DDT by humans, the surviving bed bugs evolved thicker, denser wax-like exoskeletons that could withstand the chemicals in pesticides. American entomologist Suba Reddy Parry found that bed bugs have evolved the ability to produce more p450 enzymes, which can speed up the metabolism of active substances in pesticides. So even if DDT is removed now, the bugs won't be scared anymore.
Today, whether it is a village or a city, whether it is a humble house or a mansion, bed bugs may live. This common but uncommon small insect is not picky about its environment and can change itself according to different hosts. This ability to "adapt to change" may be an important reason why the bed bug outperformed the dinosaurs, the former overlords of the earth, and is still active on the earth today. They rely on this great ability to adapt and continue to be roommates with humans. And for humans, the war with bed bugs will continue.