Description and Habits
Bed bugs are small, brownish, flattened insects that feed solely on the blood of animals. Although the common bed bug (Cimex lectularius) prefers feeding on humans, it will also bite other warm-blooded animals, including dogs, cats, birds and rodents. It has done so since ancient times; bed bugs are mentioned in medieval European texts and classical Greek writings back to the time of Aristotle.
Adult bed bugs are about 3/16” long and reddish-brown, with oval-shaped, flattened bodies. They are sometimes mistaken for ticks, cockroaches, carpet beetles or other household insects. The immature bed bugs (nymphs) resemble the adults, but are smaller and lighter in color. Bed bugs do not fly, and they don’t jump like fleas do ― but they can crawl rapidly over floors, walls, ceilings and other surfaces. Adult females lay their eggs in secluded places, depositing 1, 2 or more eggs per day, potentially hundreds during their lifetime. The eggs are tiny (about the size of a dust spec), whitish and hard to see without magnification, especially on light-colored surfaces. When first laid, the eggs are sticky, causing them to adhere to surfaces. At room temperatures, bed bug eggs hatch in about a week. Newly emerged nymphs are straw-colored and no bigger than a pinhead.
As bed bugs grow they molt, shedding their skin five times before reaching maturity. A blood meal is needed between each successive molt. Adult females also must feed in order to lay eggs. Under favorable conditions (70-80°F), the bugs can mature fully in as little as a month, producing multiple generations per year. Cooler temperatures or limited access to blood prolong the development time.
Bed bugs are very resilient. Nymphs and adults can persist months without feeding which is unusual for most insects. The ability to survive without a blood meal is longer at cooler temperatures ― potentially up to a year or longer at 55°F or less. In temperature-controlled buildings, a more typical duration is about 2 to 6 months. Consequently, it is usually impractical to leave buildings unoccupied in hopes of ‘starving out’ an infestation. When infested dwellings such as apartments are vacated, bed bugs often disperse to nearby units, or reduce their activity until the unit is reoccupied.
Bed bugs are active mainly at night. During the daytime, they prefer to hide close to where people sleep. Their flattened bodies enable them to fit into tiny crevices--especially those associated with mattresses, box springs, bed frames and headboards. Bed bugs do not have nests like ants or bees, but do tend to congregate in habitual hiding places. Characteristically, these areas are marked by dark spotting and staining, which is the dried excrement of the bugs. Also present will be hatched and un-hatched eggs, the tannish shed skins of maturing nymphs, and the bugs themselves. Another possible sign are rusty or reddish smears on bed sheets or mattresses from crushed engorged bed bugs. Although it’s often stated that bed bugs have a telltale “buggy” odor, the smell is seldom evident except in extreme infestations and should not be relied upon for detection.
Bed bugs usually bite people at night while they are sleeping. Hungry bed bugs may also feed during the daytime, especially if this is when the occupant normally sleeps. They feed by piercing the skin with an elongated beak through which they withdraw blood. Engorgement of the bed bug takes roughly three to 10 minutes, but because the bite is painless, the person seldom realizes they are being bitten. Bed bugs normally do not reside on people like head or body lice do; instead, immediately after feeding, bed bugs crawl to a secluded location to digest their meal. Symptoms after being bitten by bed bugs vary from person to person. Many develop an itchy red welt within a day or so of the bite. Others have little or no reaction. Sometimes the reaction is delayed days or even weeks after the actual bite occurs, which can make it difficult to determine where or when bites actually occurred. Studies conducted in bed bug-infested apartments suggest about 30 percent of people do not react even when bitten repeatedly over time, and there is still higher incidence of non-reactivity among the elderly. Unlike flea bites, which occur mainly around the lower legs and ankles, bed bugs feed on any skin exposed while sleeping (face, neck, shoulders, back, arms, legs, etc.). The welts and itching are often wrongly attributed to other causes, such as mosquitoes. For these reasons, infestations may go a long time unnoticed, and can become quite large before being detected.
The likelihood of bed bugs increases if the affected individual has been traveling, or if they have acquired used beds or furnishings before symptoms started to appear. Bed bugs also are suspect if you wake up with itchy welts you did not have when you went to sleep. It’s important to recognize, however, that not all bite-like reactions are due to bed bugs. Confirmation requires finding and identifying the bed bugs, shed skins, fecal spots, etc., which often requires the help of a professional. (Other possible sources of irritation that may be mistaken for bed bugs are discussed in University of Kentucky entomology fact sheet Invisible Itches: Insect and Non-Insect Causes).
A common concern with bed bugs is whether or not they transmit diseases. Although bed bugs can harbor various pathogens, transmission to humans has not been proven and is considered unlikely. Their medical significance is most commonly attributed to itching and inflammation from their bites. Antihistamines and corticosteroids may be prescribed to reduce allergic reactions, and antiseptic or antibiotic ointments to prevent infection. Though not known to carry diseases, bed bugs can substantially reduce quality of life by causing discomfort, sleeplessness, anxiety, and embarrassment. According to some health experts, the added stress from living with bed bugs can have a significant impact on the emotional health and well-being of certain individuals.
Conventional insect repellents, like those used to deter ticks and mosquitoes, do not appear to be as effective against bed bugs. Therefore, attempting to avoid being bitten by applying insect repellent at bedtime is not recommended. Sleeping with the lights on is also not likely to deter hungry bed bugs, as they will adjust their feeding cycle to the host’s sleeping patterns.
Information obtained from http://www.ca.uky.edu/entomology/entfacts/ef636.asp