Bed bugs, or cimex lectularis, are small parasites ranging in size from poppy seeds to apple seeds (adults are 3/16 inch long). They are flat, oval, reddish-brown in color, and wingless. Bed bugs undergo a gradual metamorphosis with egg, nymph, and adult stages.
Under favorable conditions, they can complete development in as little as a month, producing three or more generations per year. Entomologists estimate bed bugs feed weekly, and prefer human hosts, but will also feed on family pets. They can survive three to four months without nourishment, but need to feed between each molt.