Common Bed Bug

Origin: It is believed that this bug originally evolved with bats living in caves in the Middle East, but in the United States it appears now to be wholly a human pest. It has been associated with humans for thousands of years.

Biology: While this species is not associated with the spread of any diseases, its bite can have a serious effect on people who are sensitive to its saliva, and swelling and severe itching or other immune system reactions may be common. The bite itself is generally painless. The Human bed bug is nocturnal, feeding only at night when people are asleep. During the daylight hours it hides in any available crack or hole in the immediate area. The presence of bedbugs may be determined by an unusual “sweet” odor in the room. Females lay their eggs by gluing them to hidden surfaces, laying several eggs each day with a total of about 200 eggs. There are 5 instar stages to the nymphs, and the growth to the adult stage takes about a month and a half, although in the absence of a blood source the nymph may lay dormant for long periods. The adults can live over a year, and in the absence of human hosts they have been known to feed on birds and rodents.

Identification: Bed bugs in general are wingless insects with an extremely flattened body from top to bottom, except when they are engorged with blood. They have a large, round abdomen, long 4-segmented antennae, and a small prothorax that flares to the sides. Their mouth is a short, 3-segmented proboscis that is held below the body when at rest. The human bed bug is distinguished from other species by the antennae, where the last segment is shorter than the segment before it, the fringe of hairs along the sides of the pronotum are very short, and the front of the pronotum is deeply concave. Evidence may include bites on occupants of the structure, although a PMP should not attempt to diagnose a bite mark. There also are often small spots of blood on sheets or mattresses, left by the departing bug following its meal. Feeding by adults may last for around 15 minutes.

Characteristics Important in Control: Control relies on a thorough inspection of a structure to determine hiding places of the bugs, thorough cleaning of mattresses and bed coverings, and a thorough application of a residual insecticide to all possible cracks, crevices, holes, or other hiding places in the room. Vacuuming with a high-powered vacuum will help to remove many of the pests that are hiding.


Bed bugs are blood-sucking insects in the family Cimicidae. Both nymphs and adults feed on humans mostly at night, a time when it is difficult to detect their stealthy habits.

Cimex lectularius is a cosmopolitan, or widely distributed, species, most frequently found in the northern temperate climates of North America, Europe, and Central Asia. It occurs more sporadically in southern temperate regions. In tropical regions, C. hemipterus is the dominant species, but this species does not occur in California. The most common species found in California is C. lectularius.

The growth and development of C. lectularius is optimal when it feeds on humans; however this insect also feeds on other species of mammals and birds found near the home including chickens, mice, rats, and rabbits.

Until recently, bed bug infestations were thought to be associated primarily with crowded and dilapidated housing. However, such infestations have undergone a resurgence and can be found even in the finest hotel and living accommodations. The reasons for the resurgence are not totally understood but appear to involve increased human travel, ease of movement of infested luggage and items, and changes in the pesticides available to control this pest.


IDENTIFICATION AND LIFE CYCLE

Adult bed bugs are oval, wingless, about 1/5 inch long, and rusty red or mahogany. Their bodies are flattened, they have well-developed antennae, their compound eyes are small, and the area behind the head (the prothorax) expands forward on either side of the head. The immatures appear identical to the adults except for their smaller size, thinner outer skeleton (cuticle), and lighter, yellowish-white color.

Bed bugs are readily distinguished from another common blood-sucking species, conenose bugs (see Pest Notes: Conenose Bugs listed in References), by their smaller size, more rounded shape, and lack of wings as adults. Conenose, or kissing, bugs may be up to 3/4 inch long.

Female bed bugs lay 200 to 500 tiny, white eggs in batches of 10 to 50 on rough surfaces such as wood or paper. Glue-like material covers the eggs, which hatch in about 10 days. After hatching occurs, the eggshells frequently remain stuck in place.

There are five progressively larger nymphal stages, each requiring a single blood meal before molting to the next stage. The entire life cycle from egg to adult requires anywhere from 5 weeks to 4 months, depending on temperature and availability of food (blood). When temperatures are in the range of 70° to 82°F, development occurs most rapidly.

Nymphs and adults generally feed at night and hide in crevices during the day. Common hiding places include seams in mattresses and box springs, cracks in bed frames, under loose wallpaper, behind picture frames, and inside furniture and upholstery. Occasionally people pick up bed bugs in theaters or on buses and trains. They also can bring them into their home on clothing, bedding, luggage, or firewood.

Bed bugs can go without feeding for 80 to 140 days. Older stages of nymphs can survive longer without feeding than younger ones, and adults have survived without food for as long as 550 days. A bed bug can take six times its weight in blood, and feeding can take 3 to 10 minutes. Adults live about 10 months, and there can be up to 3 to 4 generations of bed bugs per year.


DAMAGE

Bed bugs feed on humans, usually at night when they are asleep. They feed by piercing the skin with their elongated mouthparts, which consist of two stylets that normally fold under their body when at rest but fully extend during blood-meal feeding. One stylet has a groove that carries saliva into the wound, while the other has a groove through which body fluids from the host are taken in.

A single feeding may take up to 10 minutes, and feels like a pin prick, but because feeding usually occurs at night when people are asleep they are not aware they have been bitten until afterwards. However, saliva injected during the feeding can later produce large swellings on the skin that itch and may become irritated and infected when scratched. Swelling may not develop until a day or more after feeding, and some people do not show symptoms. Bed bugs currently are not considered to be disease carriers.

Distinguishing bed bug bites from the bites of other arthropods such as mosquitoes, fleas, and spiders is difficult. People often confuse itching bed bug welts for mosquito bites. The only way you really can confirm bed bugs are the cause is to find the bugs in your bed or bedroom. Often people are bitten when traveling, making diagnosis even more difficult.

In addition to the direct injury to humans, bed bugs have stink glands that leave odors. They also leave unsightly fecal spots on bed sheets and around their hiding places. These spots are darkish red in color, roughly round, and can be very small.


MANAGEMENT

Managing a bed bug infestation is a difficult task that requires removal or treatment of all infested material and follow-up monitoring to ensure the infestation has been eliminated and does not return. Management will require employing several nonchemical methods such as vacuuming, washing bedding at a high temperature, using steam or heat treatment, and sealing up hiding places.

Insecticides may be required to eliminate serious infestations; however few active ingredients are federally registered for bed bugs for over-the-counter use. At the professional control level, there are more registered products; however, resistance among bed bug populations is common, and low-level infestations are difficult to detect. There has been some success combining chemical and nonchemical products with increased sanitation and habitat modification.

Monitoring and Detection. You can detect a bed bug infestation by searching for the pests or their fecal spots, egg cases, and shed skins (exuviae). Current research reports more than 85% of bed bugs are found in or near the bed, so inspections for infestations should focus on the mattress, bed frame, and headboard areas. Lift the mattress and inspect all seams and surfaces as well as the box springs. You may need to dismantle the bed. Use a flashlight to aid the inspection process.

Remember, these nocturnal insects are small. Although you can see adults and aggregations of nymphs with the unaided eye, seeing the eggs requires a hand-magnifying lens. It may be easier to detect dark spots of dried bed bug excrement or the insects’ light-colored shed skins. A foul, rotting, bloody-meat smell might be present in heavily infested areas.

In addition to the bed area, the remaining 15% of infestations usually are in upholstered furniture other than beds, in bedroom cabinets, along baseboards, under wallpaper, and in carpets, wall hangings and similar hiding spots. Bed bugs prefer fabric or wood surfaces to metal or plastic. For heavy infestations, adjoining rooms, filing areas, and clutter can be out-of-way shelters. It takes patience and perseverance to find low-level infestations of such a persistent, nagging problem.

Recent research has shown searching with dogs can be an effective method for finding bed bug infestations. Under laboratory and simulated-field conditions, using dogs to search for bed bugs was 97% effective. Other recent research indicates using small, double-cupped monitors that are easily installed on the leg ends of beds trapped six times more bed bugs than were found from human visual searches alone. This trap, Interceptor, is commercially available.

A new university study indicates an airborne aggregation pheromone, a behavior-modifying chemical, might help control infestation levels. With this new research, hopefully traps attractive to bed bugs soon will be commercially available.

Prevention. People usually bring bed bugs into their homes, in luggage or on clothes, after visiting an infested dwelling or hotel. If you travel frequently, watch for signs of bed bugs in your hotel room by checking under sheets and inspecting mattresses, especially if you have been bitten. If you suspect bed bugs, check your luggage before leaving and wash all your clothes as soon as you get home.

You also can bring bed bugs into your home on bedding or furniture. If you purchase second-hand furniture, especially beds or mattresses, thoroughly inspect the item before bringing it into your home. If you remove infested mattresses or furniture from your home, do not leave it on the curb or porch. Take it immediately to the dump.

Managers of hotels, furnished apartments, dormitories, homeless shelters, and other facilities that house transient populations need to train staff to recognize signs of bed bug activity and take action as soon as they find an infestation. One proactive step a manager can take is to regularly replace beds, mattress, and bedding materials. Frequent laundering of bedding and placing items that could be infested in walk-in freezers during tenant change and turnover can help prevent the spread of bed bugs.

It is much easier to control a population when the infestation is small. Keep clutter down, so it is easier to inspect and bed bugs have fewer hiding places. Also, seal up cracks, crevices, and holes in bedding or furniture and other potential hiding sites.

Nonchemical Management. In addition to preventing the introduction of bed bugs, a number of other nonchemical control methods can help manage this pest. These methods are directed at killing or removing bugs or restricting access to beds or bedding materials.

You can remove bed bugs and eggs with the suction wand of a strong vacuum; however, you must target the vacuum on the seams of mattresses and box springs, along perimeters of carpets, under baseboards, and in other areas where bed bugs live. A single vacuuming rarely gets all bugs and eggs and, therefore, should be repeated. Portable steam cleaners can also be used to clean mattresses and furniture.

Commercial heating services are available to treat entire rooms in homes for bed bug infestations. The current label use for commercial heating services is 140°F for two hours or 130°F for three hours, which will kill most bed bugs and eggs. In California, providers of heat services must be licensed and bonded by the Structural Pest Control Board when treating for wood destroying pests. Chilling to a temperature of 32°F or lower and maintaining this temperature for several days also will kill bed bugs.

For suspected infestations in clothing or bedding, a home laundry drier is very good at killing bed bugs; only 10 to 15 minutes exposure is needed.

Mattress encasements specifically designed to keep out bed bugs are commercially available. Encasements are particularly useful for hotels or other facilities with many beds; however, their effectiveness at excluding bed bugs has not been thoroughly researched. In many cases, the best approach may be to throw out the mattress, clean the area thoroughly, and install a new mattress—with or without an encasement.

Other management practices include sealing up hiding places such as cracks and crevices in walls and around windows and doors where bed bugs can hide. As a temporary measure, you can exclude bed bugs from clean beds by coating bed legs with petroleum jelly or placing them inside glass jars or metal cans, which are too slippery for bed bugs to climb.

Insecticides. Insecticides alone won’t control bed bug infestations. Their use must be combined with a program of removing and cleaning infested beds, bedding, and other harborage sites then following up with a regular detection program to ensure treatment was effective.

The most effective bed bug pesticides are available to commercial pesticide applicators only. Professionals also have the equipment and expertise that allow a more effective application of insecticides than residents could do themselves. In addition, professionals have the training to detect and isolate infestations, which often allows for more effective control.

Insecticides may be applied as liquids directly to cracks, crevices, bed frames, baseboards, or similar sites, or they may be applied as dusts in cracks and crevices. Pesticides generally are not applied to mattresses or bedding because of risk to people.


Liquid insecticide formulations include:

* Products containing the botanical insecticide pyrethrin, which gives quick knockdown but little long-term control;
* Various synthetic pyrethroid products (cyhalothrin, bifenthrin, deltamethrin, and permethrin); and
* Newer types of products including the pyrrole insecticide chlorfenapyr (Phantom) and the insect growth regulator hydroprene (Gentrol), which cause sterility in adults.

There is growing interest in the last two products, because some bed bug populations have developed resistance to pyrethroid insecticides and no longer can be effectively controlled by them. However, both newer products take up to several days to be effective.

Insecticides applied as dusts cling to the pest’s cuticle, wearing away the insect’s protective wax covering or poisoning the insect when it grooms itself. Several dust products used in bed bug management include boric acid, diatomaceous earth, fumed silica, and formulations of pyrethroids. These materials can provide long-term control as part of an integrated program if they are placed in out of-the-way places—such as under baseboards or in wall voids—that don’t get wet.

Do-It-Yourself Treatments. Although over-the-counter pesticide products that have “bed bug control” written on the label can be found on store shelves, they generally are not recommended. Performance of these products under actual field conditions is not known. If you need to use a pesticide, you are better off hiring a licensed, professional pesticide applicator with experience in treating bed bugs (see Pest Notes: Hiring A Pest Control Company listed in the References).

Residents do have an important role to play when their homes are infested with bed bugs. Once professional treatment has occurred, you should continue to monitor for bed bugs daily. Also, keep down clutter and vacuum previously infested areas regularly.