Bedbugs, known scientifically as Cimex lectularius (Cimicidae) are small wingless insects that feed exclusively on the blood of warm-blooded animals. Humans are ideal hosts for them.
Over millions of years, bedbugs have evolved as nest parasites - inhabiting the nests of birds and the roosts of bats. Some of them have learned to adapt to the human environment.
Newborns, called hatchlings or nymphs, are tiny but visible, about the size of a poppy seed, while adults grow to about 0.25 inches long. Their shape is oval and flattened. Nymphs, eggs, and adults are visible to the naked eye.
They are called bedbugs because of their preferred habitat in human homes: sofas, bed mattresses, and other soft furnishings.
Bedbugs are seen as a growing problem within all types of dwellings, including private homes, dormitories, cruise ships, army barracks, and shelters.
When seen close up, they may have a white, light tan to a deep brown or burnt orange color. Just after molting, most of them are plain white. When they have fed, a dark red or black blob may be observed within their body. They will instinctively seek shelter in dark cracks and crevices when disturbed.
Contents of this article:
Fast facts on bedbugs
Here are some key points about bedbugs. More detail and supporting information is in the main article.
- Bedbugs are small wingless insects that feed on the blood of warm-blooded animals
- Most bedbugs feed on their hosts while they are asleep
- Peak time for feeding is about 1 hour before sunrise
- A female bedbug lays approximately five eggs in 1 day and about 500 during her lifetime
- Bites can take up to 9 days to become visible
Spotting signs of bedbugs
An example of bedbug bites.
The most obvious sign that there might be bedbugs in your home is that people complain of bites that occurred while they were asleep. If this happens, you should examine the bedrooms for bedbugs and signs of bedbug activity.
Look carefully into the creases in the bed linen, and seams and tufts of mattresses and box springs for bugs or eggs. The eggs will look like tiny pale poppy seeds.
Signs of bedbug activity may exist beneath loose areas of wallpaper near beds, in the corner of desks and dressers, in the laundry, and in drawers.
Look out for dark brown or reddish fecal spots (bedbug droppings, excrement). If the area has a large population of bedbugs, you may sense a coriander-like odor. The excrement is a liquid that looks either light brown or black that can either bead up or be absorbed by the material around it.
How do bedbugs feed?
The most active time for a bedbug is about 1 hour before sunrise - the peak time for feeding. However, they will try to feed at any time of day or night if they are hungry enough, and if the opportunity is there. They prefer nighttime and hate sunlight.
Bedbugs reach their host either by crawling straight towards them, or climbing a wall and then across the ceiling until they feel a heat wave, then they jump down onto their host. The bug is attracted to us by both our warmth and the presence of the CO2 (carbon dioxide) in our breath.
A bedbug is about the size of a grain of rice. This bedbug has recently had a feed.
It pierces the skin of its host with two hollow tubes. One tube injects saliva which contains anesthetics, so that the host feels nothing, and anticoagulants so that the blood flows out freely. The other tube sucks the blood in.
Feeding takes 2-5 minutes, after which the bug returns to its hiding place. Bites are not noticeable by the host until at least a few minutes or some hours afterward.
Bedbugs will feed every 5 to 10 days. They can, however, last for several months without feeding. If there is no food around they can become dormant for over a year. A well-fed bedbug has a lifespan of about 6 to 9 months.
How do bedbugs reproduce?
Bedbugs reproduce by traumatic insemination, also known as hypodermic insemination. The males pierce the females with their genitalia anywhere on their abdomen and release sperm into the body cavity. The sperm travels through the female's tissues until it reaches the ovaries, resulting in fertilization.
A female bedbug lays approximately five eggs in 1 day and about 500 during her lifetime. Eggs are about 1-millimeter-long and are visible to the naked eye. They have a milky-white tinge.
The eggs take about 2 weeks to hatch. The nymphs (baby bedbugs) start feeding as soon as they hatch and pass through five molting stages before reaching maturity. During each molting stage, they need to feed once. It takes about 5 weeks to reach maturity if they are at room-temperature.
Bedbugs can only reproduce when they have reached maturity.
Bedbugs may get into a new home as stowaways when luggage, furniture, and bedding is moved into a new home - especially in the case of second-hand furniture. People should be careful when purchasing second-hand furniture - a careful visual inspection should result in detecting them, if any are present.
Even vacant and seemingly clean homes may have bedbugs in them - they can survive for many months without any food. They can also move from apartment to apartment through hollows in walls and holes and tubes that wires and pipes go through.
A bat or bird that flies into the home could introduce bedbugs, too.
What happens when you are bitten?
Most bedbugs feed on their hosts while they are asleep. The host supplies them with blood in a painless way, never knowing it is happening. While feeding, they inject a small amount of saliva into the host's skin. If they feed on one particular person for several weeks, the individual may become more sensitized to their saliva (the anesthetic that it contains); eventually, the host can develop a mild to intense allergic response.
People who have become sensitive to bedbug saliva will develop lesions similar to mosquito or flea bites. Most humans will think they have been bitten by an insect and never realize who the true culprit was.
Bites can sometimes take several days to become visible. Unlike flea bites, bedbug bites do not usually have a red dot in the center.
Bedbugs, like fleas, tend to bite in rows. There are likely to be two or three bites in each row. This is probably because the bedbug is disturbed while feeding, and then comes back about half an inch further down for its next bite.
About 50 percent of people who are bitten show no symptoms at all and do not know it happened. This makes it more difficult to prevent or identify potential infestations. Some individuals, however, may become ill and nauseous. It is possible to get skin infections and scars from scratching the bites.
Very rarely, people might have an anaphylactic reaction to bedbug bites. It is possible to have an asthmatic reaction to bedbugs, but cases are very rare.
Treatment of bites
Most bites resolve within 1-2 weeks. Treatment focuses on relieving symptoms, and include:
- Topical creams, such as cortisone can relieve itching
- Avoid scratching as this can cause infection
- If infection occurs because of the bite, an oral antibiotic may be prescribed
- If there is a severe allergic reaction, oral corticosteroids may be prescribed
- Antihistamines may also help relieve allergic reactions
Do bedbugs transmit disease?
There is no record of a disease being transmitted or caused by bedbugs.
A review conducted in 2009 found that while they are highly resistant to various ways of getting rid of them, bedbugs seem to be more of a nuisance than a serious health problem, but the possibility that they could one day serve as a vehicle for disease has not been well researched.
Some say hepatitis B or Chagas disease could potentially be transmitted by bedbugs if the settings were right. However, bedbugs are not currently known to transmit any diseases.
The biggest risk for humans comes from secondary bacterial infection, which in this case would be as a result of scratching the skin. Scratching, if it breaks the skin, allows bacteria to penetrate - but the bacteria would not have been from the bedbug.
Although they are not known to carry diseases, bedbugs can affect the quality of life of a person who has been bitten, causing distress, discomfort, embarrassment, and unsettled sleep.
Controlling an infestation
A bedbug nymph ingests a blood meal from a human host
Since they can hide in so many places, they are not easy to eradicate. It is advisable to get a professional in pest control. Experts know where to look for them, as well as how to get rid of them.
You can help the pest control professional by removing excess clutter from your house, giving the bedbugs fewer places to hide; this makes inspection and eradication less difficult.
Some pest control companies may request that furniture is pulled away from walls, and mattresses and box springs stood on edge before they come in, while others prefer everything to be left where it is so that they can check before moving them themselves.
Scientists at Ohio State University have determined that combining bedbugs' own chemical signals with a common insect control agent makes that treatment more effective at killing the bugs.
Encasing your bed
It is possible to encase both the mattress and box spring in a proactive cover, as some people do for allergy relief. Some pest control firms sell them, as do a number of retail outlets.
Once encased, any bedbug trapped inside will eventually die. Some people keep their new beds encased as it prevents the bugs from getting into the mattress and crevices and makes it easier to keep the surface clean and bug-free. It is important to remember that encasements do not stop bedbugs from crawling onto them.