Mature bed bugs are about the size of an apple seed, and immature bed bugs, or nymphs, are the size of a poppy seed. Bed bugs resemble tiny brown or black specks of dirt on bedding or mattresses.
Bed bugs feed on the blood of humans and other animals. While they don't fly, they move quickly, multiply exponentially and infest mattresses, box springs, bed linens and headboards.
Bed bugs mainly feed at night. They pierce the skin and draw blood, feeding until they become engorged. Itchy, red bumps form at the bite site after several hours. While bed bugs are invasive pests, they are not known to spread diseases to humans.