Bedbugs or bed bugs are small parasitic insects of the family Cimicidae (most commonly Cimex lectularius). The term usually refers to species that prefer to feed on human blood. All insects in this family live by feeding exclusively on the blood of warm-blooded animals.  The name ‘bedbug’ is derived from the insect’s preferred habitat of houses and especially beds or other areas where people sleep.

Bedbugs, though not strictly nocturnal, are mainly active at night and are capable of feeding unnoticed on their hosts.
A number of health effects may occur due to bed bugs including skin rashes, psychological effects and allergic symptoms. Diagnosis involves both finding bed bugs and the occurrence of compatible symptoms. Treatment is otherwise symptomatic.

Physical
Adult bedbugs are reddish-brown, flattened, oval, and wingless. Bedbugs have microscopic hairs that give them a banded appearance. Adults grow to 4–5 mm in length and 1.5–3 mm wide. Newly hatched nymphs are translucent, lighter in color and become browner as they molt and reach maturity.Bedbugs use pheromones and kairomones to communicate regarding nesting locations, attacks, and reproduction.
The life span of bedbugs varies by species and is also dependent on feeding. Bedbugs can survive a wide range of temperatures and atmospheric compositions. Below 16.1 °C (61.0 °F), adults enter semi-hibernation and can survive longer. Bedbugs can survive for at least five days at ?10 °C (14.0 °F) but will die after 15 minutes of exposure to ?32 °C (?26 °F).They show high desiccation tolerance, surviving low humidity and a 35–40 °C range even with loss of one-third of body weight; earlier life stages are more susceptible to drying out than later ones. The thermal death point for C. lectularius is high: 45 °C (113 °F) and all stages of life are killed by 7 minutes of exposure to 46 °C (115 °F). Bedbugs apparently cannot survive high concentrations of carbon dioxide for very long; exposure to nearly-pure nitrogen atmospheres, however, appears to have relatively little effect even after 72 hours.

Feeding habits
Bedbugs are obligatory hematophagous (bloodsucking) insects. Most species feed on humans only when other prey are unavailable. Bedbugs are attracted to their hosts primarily by carbon dioxide, secondarily by warmth, and also by certain chemicals.A bedbug pierces the skin of its host with two hollow feeding tubes. With one tube it injects its saliva, which contains anticoagulants and anesthetics, while with the other it withdraws the blood of its host. After feeding for about five minutes, the bug returns to its hiding place. Although bedbugs can live for a year without feeding, they normally try to feed every five to ten days. In cold weather, bedbugs can live for about a year; at temperatures more conducive to activity and feeding, about 5 months
Health effects and infestations
A number of health effects may occur due to bedbugs including skin rashes, psychological effects and allergic symptoms. Bedbug bites or cimicosis may lead to a range of skin manifestations from no visible effects to prominent blisters. Diagnosis involves both finding bedbugs and the occurrence of compatible symptoms. Treatment involves the elimination of the insect but is otherwise symptomatic.
Because infestation of human habitats has been on the increase in developed countries, bedbug bites and related conditions have been on the rise as well, since the 1980s-1990s.The exact causes of this resurgence remain unclear; it is variously ascribed to greater foreign travel, more frequent exchange of second-hand furnishings among homes, a greater focus on control of other pests resulting in neglect of bedbug countermeasures, and increasing resistance to pesticides. Bedbugs have been known human parasites for thousands of years.

Cause
Dwellings can become infested with bedbugs in a variety of ways: from bugs and eggs that “hitchhiked in” on clothing and luggage, from infested items (e.g., furniture, clothes) brought in, from a nearby dwelling or infested item, if there are easy routes, or from wild animals (e.g. bats, birds) and pets brought in.

Locations/Detection
Bedbugs can be found on their own but often congregate once established. They usually remain close to hosts, commonly in or near beds or couches. Nesting locations can vary greatly, however, including luggage, vehicles, furniture and bedside clutter. Bedbugs may also nest near animals that have nested within a dwelling, such as bats, birds, or rodents.
Bedbugs are elusive and usually nocturnal, which can make them hard to spot. Bedbugs often lodge unnoticed in dark crevices, and eggs can be nestled in fabric seams. Aside from bite symptoms, signs include fecal spots, blood smears on sheets, and molts.