The common bedbug (Cimex lectularius) is the best adapted to human environments. It is now found throughout the world and lives off the blood of humans. Adult bedbugs are a reddish-brown, flattened, oval, and wingless. A common misconception is that they are not visible to the naked eye. Adults grow to 4-5 mm in length and do not move quickly enough to escape your notice. Newly hatched nymphs are translucent, lighter in color and continue to become browner and moult as they reach maturity. Bedbugs are generally active only at dawn, with a peak feeding period about an hour before sunrise. Attracted by warmth and the presence of carbon dioxide, the bug pierces the skin of its host with two hollow tubes.
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.
In most observed cases a small, hard, swollen, white welt may develop at the site of each bedbug bite. This is often surrounded by a slightly raised red bump and is usually accompanied by severe itching that lasts for several hours to days. Later, however, the welts subside but tend not to disappear like those from mosquitos, and persist for up to several weeks. This usually depends on the person’s skin type, environment and the species of bug.