Since the mid-1990s, bed bugs have become a serious pest around the world, including North America. It is believed the increase in international travel, coupled with the banning of pesticides such as DDT, created the opportunity for bed bugs to spread and multiply.
Bed bugs can infest clean homes just as easily as unsanitary ones. They attach themselves to bedding and clothing, even furniture and luggage. Almost anything that comes into contact with bed bugs can help them spread. They can move between apartments via false ceilings and duct work.
Bed bugs are insects of the order Hemiptera - True Bugs. The main species that affects humans in the US is the common bed bug, Cimex lectularius. Its close relative, the tropical bed bug, Cimex hemipterus, is found in southern states such as Florida.
The adults of both species are reddish brown in color. Their flat shape enables them to hide unseen in minute cracks when not feeding. The females are slightly larger than the males, growing to 0.2 inches long and 0.1 inches wide.
They can ingest up to six times their own weight in blood in one feed, so their abdomens quickly become bloated. Neither sex can fly.
Bed bugs emit pheromones to communicate information about nesting and feeding locations, as well as threats and for reproduction. These pheromones also enable them to congregate and if enough bed bugs are disturbed they may produce a distinctive pungent odor.
Bed bugs defecate regularly and abundantly, resulting in an unpleasant smell and the telltale brown spots on bed sheets.
These pests are remarkably hardy, making them difficult to eradicate. At low temperatures, adults can live for more than a year without feeding.
They can survive a wide range of temperatures, entering a state of semi-hibernation below 60°F. However, extended periods below 14°F or above 113°F will kill them.
A bed bug starts life as a small white egg. After two weeks, a nymph will hatch which will go through five skin changes before becoming an adult. With each skin change, the shed skin is left behind, which is often an indicator of a bed bug infestation. Nymphs look similar to adults but are lighter in color.
To grow, a nymph must have at least one meal of blood between skin changes. Typically, they will feed daily but can survive for weeks between meals when necessary. If the conditions are right and food plentiful, a bed bug can reach maturity in as little as five weeks although two to three months is more normal.
After the final skin molt, males will seek out females for reproduction. With adequate food, a female can lay three to five eggs a day over a period of several months. In normal circumstances, a bed bug can live for between five months and a year. A female can lay up to 500 eggs in her lifetime.
Adult bed bugs will usually feed every three to ten days, with nymphs feeding more frequently. It is estimated that it takes between five to ten minutes for a bed bug to complete its feeding.
Bed bugs find their victims by detecting a combination of carbon dioxide and body warmth, but can also be attracted by pheromones produced by other bed bugs. They prefer to feed on exposed areas of skin, such as the neck, face or arms, using a needle-like projection on their head to pierce the victim’s skin.
Blood pressure from the victim forces the blood into the bed bug. As they feed, they inject saliva that contains a mild anticoagulant into the wound.
Once engorged with blood, the pest leaves the victim to find somewhere safe to digest the meal. Bed bugs excrete droppings of blood, which may appear near the feeding site or some distance away.
For the majority of people bitten by bed bugs, the bites are of little consequence especially if they are few and do not even itch. Bites are often found in groups of three or four, an inch or so apart and frequently in a straight line.
Due to the injection of minute amounts of saliva into the wound, some people develop an allergic reaction. The severity of that reaction varies between individuals. For some, the bite may simply become an itchy red spot. For others, the bite can cause swelling, turn into blisters or even develop pus. Rashes can be caused by over-zealous scratching of the bitten area.
Diseases and effects
Bed bugs are not known to transmit any diseases. There is also no evidence of disease being transmitted from bed bug feces when scratching a bite.
Often, the greatest harm caused by bed bugs is psychological. Deprivation of sleep can have a profound effect on individuals. Coupled with the stigma of a bed bug infestation, these small pests can have a devastating impact on the quality of life of their victims.