The common bed bug (Cimex lectularius) has long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. The Environmental Protection Agency (EPA), the Centers for Disease Control and Prevention (CDC), and the United States Department of Agriculture (USDA) all consider bed bugs a public health pest. However, unlike most public health pests, bed bugs are not known to transmit or spread disease.
They can, however, cause other public health issues, so it’s important to pay close attention to preventing and controlling bed bugs.
Experts believe the recent increase in bed bugs in the United States may be due to more travel, lack of knowledge about preventing infestations, increased resistance of bed bugs to pesticides, and ineffective pest control practices.
The good news is that there are ways to control bed bugs. Getting good, solid information is the first step in both prevention and control. While there is no chemical quick fix, there are effective strategies to control bed bugs involving both non-chemical and chemical methods.
Bed bugs can be hard to find and identify, given their small size and their habit of staying hidden. It helps to know what they look like, since the various life stages have different forms.
Bed Bugs Appearance and Life Cycle
Knowing what to look for is the first step in identifying and controlling bed bugs. There are many bugs that look like bed bugs, so an accurate identification is a critical first step to avoid costly treatment for the wrong bug.
Adult bed bugs, in general, are:
- about the size of an apple seed (5-7 mm or 3/16 – 1/4 inch long);
- long and brown, with a flat, oval-shaped body (if not fed recently);
- balloon-like, reddish-brown, and more elongated (if fed recently);
- a “true bug” (characteristics of true bugs include a beak with three segments;
- antenna that have four parts; wings that are not used for flying; and short, golden-colored hairs); and smelly, with a “musty-sweetish” odor produced through glands on the lower side of the body.
Young bed bugs (also called nymphs), in general, are: smaller, translucent or whitish-yellow in color; and if not recently fed, can be nearly invisible to the naked eye because of coloring and size.
Bed bug eggs, in general, are:
- tiny, the size of a pinhead;
- pearl-white in color; and
- marked by an eye spot if more than five days old.
The life cycle of a bed bug is shown in the photograph below. During its lifetime, a bed bug will go through the following stages (Starting from the top left, moving counterclockwise):
- Eggs (1mm).
- 1 st stage nymph (1.5 mm).
- 2 nd stage nymph (2 mm).
- 3 rd stage nymph (2.5 mm).
- 4 th stage nymph (3 mm).
- 5th stage nymph (4.5 mm).
- Unfed adult female.
- Unfed adult male.
How to Find Bed Bugs
If you have a bed bug infestation, it is best to find it early, before the infestation becomes established or spreads. Treating a minor infestation, while an inconvenience, is far less costly and easier than treating the same infestation after it becomes more widespread.
However, low-level infestations are also much more challenging to find and correctly identify. Other insects, such as carpet beetles, can be easily mistaken for bed bugs. If you misidentify a bed bug infestation, it gives the bugs more time to spread to other areas of the house or hitchhike a ride to someone’s house to start a new infestation.
Bites on the skin are a poor indicator of a bed bug infestation. Bed bug bites can look like bites from other insects (such as mosquitoes or chiggers), rashes (such as eczema or fungal infections), or even hives. Some people do not react to bed bug bites at all.
Looking for Signs of Bed Bugs
A more accurate way to identify a possible infestation is to look for physical signs of bed bugs. When cleaning, changing bedding, or staying away from home, look for:
- Rusty or reddish stains on bed sheets or mattresses caused by bed bugs being crushed.
- Dark spots (about this size: •), which are bed bug excrement and may bleed on the fabric like a marker would.
- Eggs and eggshells, which are tiny (about 1mm) and pale yellow skins that nymphs shed as they grow larger.
- Live bed bugs.
Where Bed Bugs Hide
When not feeding, bed bugs hide in a variety of places. Around the bed, they can be found near the piping, seams and tags of the mattress and box spring, and in cracks on the bed frame and headboard.
If the room is heavily infested, you may find bed bugs:
- In the seams of chairs and couches, between cushions, in the folds of curtains.
- In drawer joints.
- In electrical receptacles and appliances.
- Under loose wall paper and wall hangings.
- At the junction where the wall and the ceiling meet.
- Even in the head of a screw.
Since bed bugs are only about the width of a credit card, they can squeeze into really small hiding spots. If a crack will hold a credit card, it could hide a bed bug.
Bed Bug Behavior and Habit
Understanding the behavior of bed bugs (how they eat, live, and reproduce) will help you to find an infestation before it becomes established and to monitor for the presence of bed bugs after your home has been treated.
- Appear to prefer to feed on humans, but will feed on other mammals and birds as well.
- Will readily travel 5-20 feet from established hiding places (called harborage) to feed on a host.
- Even though they are primarily active at night, if hungry they will seek hosts in full daylight.
- Feeding can take 3-12 minutes.
- The rusty or tarry spots found on bed sheets or in bug hiding places are because 20% of the time adults and large nymphs will void remains of earlier blood meals while still feeding.
Bed bugs need at least one blood meal before the individual bug can develop to the next of the six life stages.
- They can feed more than once.
- Each stage also requires the molting of skin.
To continue to mate and produce eggs, both males and females must feed at least once every 14 days.
Each female may lay 1 to 3 eggs per day and 200-500 eggs per her lifetime (6-12 months but could be longer).
Egg-to-egg life cycle may take four to five weeks under favorable conditions.
Bed bugs can survive and remain active at temperatures as low as 7°C (46°F), but they die when their body temperatures reaches 45°C (113°F).
Tropical bed bugs (Cimex hemipterus) require a higher average temperature than the common bed bug and are found in tropical and subtropical areas.