Bed bugs, known scientifically as Cimex lectularius (Cimicidae) are small wingless insects that feed by hematophagy - exclusively on the blood of warm blooded-animals. As we are warm-blooded animals, we are ideal hosts for them.
Over millions of years, bed bugs have evolved as nest parasites - inhabiting the nests of birds and the roosts of bats. Some of them have learnt to adapt to the human environment and live in our nests, i.e. our homes, and more specifically, our beds. Newborns, called hatchlings or nymphs, are tiny, about the size of a poppy seed, while adults grow to about ¼ of an inch long. Their shape is oval and flattened. Both nymphs, eggs and adults are visible to the naked eye.
They are called bed bugs because of their preferred habitat in human homes: sofas, bed mattresses and other soft furnishings.
Bed bugs are seen as a growing problem within all types of dwellings, including private homes, dormitories, cruise ships, army barracks, and shelters.
Bed bugs breed successfully in various environments and circumstances. On 12th December, 2011, experts at SRI International reported that bed bugs can inbreed and still produce healthy offspring.
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 had their feed a dark red or black blob may be observed within their body. They will instinctively seek shelter in dark cracks and crevices when disturbed.
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Fast facts on bed bugs
Here are some key points about bed bugs. More detail and supporting information is in the main article.
- Bed bugs are small wingless insects that feed on the blood of warm blooded-animals.
- As humans, we are ideal hosts for bed bugs.
- Bed bugs are so called because of their preferred habitat in human homes: sofas, bed mattresses, etc.
- Most bed bugs feed on their hosts while they are asleep.
- Peak time for feeding is about one hour before sunrise.
- Feeding takes about five minutes, after which the bug returns to its hiding place.
- A female bed bug lays approximately 5 eggs in one day and about 500 during her lifetime.
- Bites can take up to nine days to become visible.
- Unlike flea bites, bed bug bites don't have a red dot in the center.
- Bed bugs tend to bite in rows. You will likely see two or three bites all in a row.
- Bed bugs are not easy to eradicate. It is advisable to hire a professional in pest control.
Spotting signs of bed bugs
The biggest sign of bed bugs is people complaining of bites that occurred while they were asleep. If this happens, you should examine the bedrooms for bed bugs and signs of bed bug 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 bed bug 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 (bed bug droppings, excrement). If the area is very infested 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.
Dogs can be trained to sniff out live bed bugs or past infestations. A dog's sense of smell is so acute that it can pick up the scent of a single bed bug.
How dangerous are bed bugs to humans?
Most bed bugs 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. The more they feed on one particular host, say human, over a period of several weeks, the more sensitized that human becomes to their saliva. Until eventually the host develops a mild to intense allergic response.
People who have become sensitive to bed bug bites - their saliva - have lesions similar to mosquito or flea bites. Most humans will think they have been bitten by some insect, such as a mosquito, and never realize who the true culprit was.
The common bed bug, (Cimex lectularius) has adapted well to human environments. It is found in temperate climates. Cimex hemipterus is more common in tropical regions and has mainly poultry and bats as its host. Leptocimex boueti found mainly in South America, and West Africa feeds chiefly on humans and bats. Haematosiphon inodora, of North America, feeds primarily on poultry.
How do bed bugs feed?
A bed bug is about the size of a grain of rice. This bed bug has recently had a feed.
The most active time for a bed bug is about one 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.
They will reach their host either by crawling straight towards them, or climbing a wall and then across the ceiling until they feel a heat wave - when they jump down onto their host. The bug is attracted to the host by both its warmth and the presence of C02 (carbon dioxide).
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 about five 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 afterwards. Hosts, for example humans, will be aware of a bite after scratching it. Often bites may not be noticeable for several days.
Bed bugs will feed every five to ten 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 bed bug has a lifespan of about six to nine months.
How do bed bugs reproduce?
Bed bugs reproduce by traumatic insemination, also known as hypodermic insemination. The males have hypodermic genitalia, which pierce the females anywhere on their abdomen and ejaculate sperm into the body cavity. The sperm diffuse through the insides and reach the ovaries, resulting in fertilization.
A female bed bug lays approximately 5 eggs in one day and about 500 during her lifetime. Eggs are about 1 mm long and are visible to the naked eye. They have a milky-white tinge.
The eggs take about two weeks to hatch. The nymphs (baby bed bugs) 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 five weeks to reach maturity at a room-temperature environment.
Bed bugs can only reproduce when they have reached maturity.
Bed bugs 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. Perhaps we should be careful when purchasing second hand furniture at knock-down prices - a careful visual inspection should result in detecting them, if any are present.
Even vacant and seemingly clean homes may have bed bugs 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 bed bugs, and some other bugs as well.
On the next page we look at what happens if you get bitten, how to spot signs of infestation, how to get rid of bed bugs and some prevention tips including how to encase your bed.