The bedbug is an insect of the family Cimicidae that lives by hematophagy − feeding on the blood of humans and other warm−blooded hosts. Its name comes from its preferred habitat: mattresses, sofas, and other furniture. Although not strictly nocturnal, bedbugs are mainly active at night.
The common bedbug (Cimex lectularius) is the species best adapted to human environments. It is found in temperate climates throughout the world and feeds on blood.Adult bedbugs are reddish−brown, flattened, oval, and wingless, with microscopic hairs that give them a banded appearance. A common misconception is that they are not visible to the naked eye. Adults grow to 4−5 mm (1/8th − 3/16th of an inch) in length and do not move quickly enough to escape the notice of an attentive observer. In size, they are often compared to lentils or apple seeds. Newly hatched nymphs are translucent, lighter in color and become browner as they moult and reach maturity.
Bedbugs are normally active just before dawn, with a peak feeding period about an hour before sunrise. However, they may attempt to feed at other times, given the opportunity, and have been observed to feed at any time of the day. They reach their host by crawling, or sometimes climb the walls to the ceiling and jump down on feeling a heat wave. Attracted by warmth and the presence of carbon dioxide, the bug pierces the skin of its host with two hollow 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. The bites cannot usually be felt until some minutes or hours later, as a dermatological reaction to the injected agents, and the first indication of a bite usually comes from the desire to scratch the bite site. Because of their natural aversion for sunlight, bedbugs come out at night.
Although bedbugs can live for a year or eighteen months without feeding, they normally try to feed every five to ten days. Bedbugs that go dormant for lack of food often live longer than a year, while well−fed specimens typically live six to nine months. Low infestations may be difficult to detect, and it is not unusual for the victim not to even realize they have bedbugs early on. Patterns of bites in a row or a cluster are typical as they may be disturbed while feeding. Bites may be found in a variety of places on the body.