A bed bug that is sucking human blood, and its mouthparts can be seen in the picture having pierced into the skin of people.
As a blood-sucking insect, bed bugs have plagued humans for thousands of years. 70 years ago, Westerners thought they had completely defeated bed bugs, but now they are making a comeback.
When you wake up in the morning, you find a row of small red bumps running through your arms, which you didn't see last night, and now they make you itch. Are mosquitoes? louse? Or are you allergic to residual detergent on your clothes? No, the culprit is - bed bugs.
Over the past 20 years, especially since the beginning of the 21st century, this scenario has become increasingly common around the world, with cities being the hardest hit areas. Bed bugs are no longer confined to dilapidated abandoned buildings, they come into the house, even in high-end private apartments and five-star hotels. No one knows why bed bug populations have exploded in recent years, with some blaming international and cross-border travel and others blaming the ban on DDT, an insecticide. But whatever the reason, what is the way to subdue this pest?
The relationship between humans and bed bugs has deep roots. Many entomologists believe that bed bugs have plagued humans since the time of prehistoric cavemen, and that they later moved into man-made buildings from caves with primitive people. There are as many as 75 species of bed bugs, all of which suck blood, but only two kinds of blood, namely tropical bed bugs and general bed bugs, and other bed bugs suck bird blood and bat blood. One of the most common bed bugs in the United States and Europe is the general bed bug, the adult is red or dark brown and only one and a half times the size of a sesame seed. These pests have no wings and a flat body, making it easy to burrow into crevices. When eating, the blood swells the bed bug's body.
The oldest evidence of bed bugs infesting human households is a 3,500-year-old sample of bed bugs found in the ruins of an ancient Egyptian village. Nearly 1,000 years after bed bugs plagued ancient Egyptian villages, Greek and Roman scholars documented the bugs and also mentioned their medical uses. The Roman scholar Pliny the Great hinted that bed bugs could be used to treat snake bites. Until the 18th century, potions and ointments containing bed bugs and their relatives were used to treat a variety of ailments from fever to "hysteria," of which "hysteria" encompassed a variety of mental illnesses.
Today people think that the bed bug is just a nocturnal pest insect that crawls out hours before dawn to suck blood. When they suck blood, they are injected with an anesthetic that makes it almost impossible to feel the skin punctured. They are also infused with an anticoagulant that makes the victim's wound bleed incessantly. It takes 10 minutes for bed bugs to eat a full meal, and each bug only eats about once a week, but the females lay as many as 200 to 400 eggs at a time, and the larvae mature after about two months. In a room infested with bed bugs, hundreds of bed bugs may come out each night to suck blood.
Allergic reactions to bed bug saliva can make people feel itchy and appear red wounds. Although no bed bugs have been found to transmit the disease, some people have severe allergic reactions to bed bug bites, and in areas with severe pests, bed bugs can also cause anemia in infants and the elderly.
Despite its long history of infestation and the ease with which bed bugs are to reproduce, bed bugs have all but disappeared in the Western world in the 1930s with the help of the synthetic pesticide DDT.
However, as if overnight, bed bugs suddenly made a comeback. There are reports of resurgence of bed bugs in major cities around the world.
The resurgence of bed bugs is indeed sudden. Before 2004, there were almost no reports of bed bugs in the United States, but since recent years, the number of reports in this area has risen sharply and has increased. Why is that? No one knows the exact answer. Scientists have speculated that one of them is that DDT is banned. The first introduction of DDT was in the 1930s, and it has a residual effect that can persist for a long time, killing bed bugs for weeks.
Bed bugs do not respond to bait used to kill other pests, and there is no collective nest to target (in the case of ants, for example, they inadvertently carry toxins back into their nests, resulting in the destruction of entire families). Therefore, the powerful DDT has become one of the best weapons to kill bed bugs. However, the United States banned the use of DDT in 1972 because it was thought to have led to a decline in the number of vultures and eagles and was also thought to be potentially carcinogenic.
The ban on DDT may have played a role in the return of bed bugs, and scientists believe global travel may also be one of the causes. Bed bugs are most commonly found around mattresses, but they can also hide in any small space, such as cracks between floors, joints in furniture, and gaps in clothing boxes. Travelers may take bed bugs from home to hotels and take them home through luggage, and because bed bugs are so fecund, a bed bug can be a source of disaster.
The toughness of bed bugs makes it harder to get rid of them. They can survive for more than a year without eating, which allows them to survive even on furniture discarded on the side of the road. Bed bugs can hide almost anywhere, and professional insecticidalists often use a combination of multiple insecticides and desiccants to kill bed bugs. Insecticides are usually ineffective against bed bug eggs, so killing bed bugs requires at least two steps: the first is to kill the adults, and the second is to "care" for the newly hatched larvae after about two weeks. Complicating matters is the fact that some bed bugs are resistant to certain pesticides.
Many insecticiders also use heat treatment for bed bugs, i.e. applying hot air or steam to areas where bed bugs may live, and heating or freezing areas and items where pesticides cannot be used. The benefit of heat treatment and freezing is that it is effective in killing both adult and egg, but the temperature is usually required to be kept above 48.9 ° C or below the freezing point for a week to be fully effective, which is not only unfeasible but also expensive for the average family.
However, some scientists have pointed out that the lack of public awareness and related research is the biggest problem. Some people don't know about bed bugs at all, and they may be plagued by bed bugs for months and still don't know it, thinking they have a rash or a disease. Others throw away mattresses and furniture to avoid pests, others pick up cheap things to take home, and naturally pick up bed bugs. Those who eventually become aware of the insect infestation usually buy readily available pesticides to control insects, and the result of doing so is to let the bugs escape to other rooms or other apartments.
How bed bugs reproduce
Breeding is easy and harsh for female bed bugs. Bed bug breeding relies on traumatic insemination, in which the male pierces the female's abdomen with its own sharp organs, allowing the sperm to pass through the fluid in the female's body and eventually reach the ovaries. Adult females can mate multiple times, but the mating process is fatal to the larvae. To stop this from happening, the female larvae release a warning pheromone that prevents the male from mating with them.
Dead bugs
Adult bed bugs are 4 to 5 mm long and 1.5 to 3 mm wide. The newly hatched larvae have transparent bodies and are lighter in color. The lifespan of bed bugs depends on the species and what they eat. Although bed bugs may live for a year without eating, they normally eat every 5 to 10 days. In cold climates, bed bugs can live for about a year. Under conditions where temperatures are more suitable for activity and eating, bed bugs can live for 2 to 5 months.
Bed bugs can survive over a wide temperature range. Below 16.1 °C, adults enter a semi-hibernating state and can survive longer. Below -10 °C, bed bugs can live for at least 5 days. Once the temperature drops to -32 ° C, bed bugs can only live for 15 minutes. Bed bugs also have a high tolerance to dehydration, and under conditions of 35 to 40 °C and low humidity, even if the weight is reduced by 1/3, bed bugs can still survive. However, larvae are more likely to be killed than adults. Temperate bed bugs have a higher lethal temperature, reaching 45 ° C, and once the temperature exceeds 46 ° C, both adults and larvae will die within 7 minutes. Under conditions of high carbon dioxide concentrations, bed bugs do not live long. But in an atmosphere that is almost purely nitrogen, bed bugs can live at least 72 hours.
Bed bugs' natural enemies include hunting bugs, cockroaches, ants, spiders, termites and centipedes, and the toxins of kitchen ants are deadly to bed bugs. However, biological removal of bed bugs from residents' homes is not feasible. In addition, even if bed bugs had smoked human blood 90 days earlier, DNA could still be extracted from their blood, which could make bed bugs a forensic tool for identifying who had been sucked.