Adult bed bugs are light brown to reddish-brown, flattened, oval-shaped, and have no hind wings. The front wings are vestigial and reduced to pad-like structures. Bed bugs have segmented abdomens with microscopic hairs that give them a banded appearance. Adults grow to 4–5 mm long  and 1.5–3 mm wide.

Newly hatched nymphs are translucent, lighter in color, and become browner as they molt and reach maturity.  A bed bug nymph of any age that has just consumed a blood meal has a bright red, translucent abdomen, fading to brown over the next several hours, and to opaque black within two days as the insect digests its meal. Bed bugs may be mistaken for other insects, such as book lice, small cockroaches, or carpet beetles; however, when warm and active, their movements are more ant like and, like most other true bugs, they emit a characteristic disagreeable odor when crushed.  The lifespan of bed bugs varies by species and is also dependent on feeding.

Bed bugs are attracted to their hosts primarily by carbon dioxide, secondarily by warmth, and also by certain chemicals.  Bed bugs prefer exposed skin, preferably the face, neck, and arms of a sleeping person.

Bed bugs have mouth parts that saw through the skin, and inject saliva with anticoagulants and painkillers. Sensitivity of humans varies from extreme allergic reaction to no reaction at all. The bite usually produces a swelling with no red spot, but when many bugs feed on a small area, reddish spots may appear after the swelling subsides.

Although under certain cool conditions adult bed bugs can live for over a year without feeding, under typically warm conditions they try to feed at five to ten day intervals, and adults can survive for about five months without food. Younger instars cannot survive nearly as long, though even the vulnerable newly hatched first instars can survive for weeks without taking a blood meal.

Prevention Tips

Vacuum often, focusing on the edges where the floors and walls meet.

Never pick up discarded furniture from the side of the road.

Do not bring second hand furniture into your home that has been purchased at a yard sale or consignment shop without carefully inspecting it for signs of bed bugs.

Do not purchase second hand mattresses unless they are certified bed bug free.

Reduce any clutter in your home.

Encase your mattress and box spring with covers that prevent bed bugs from becoming established in the bed.