The anatomy of a bedbug is ideally suited to the way that it lives. Bedbugs’ bodies are almost flat. This makes it easy for them to hide in cracks and crevices during the day. The body is able to enlarge when it feeds on the blood of a human host. After it feeds, the bedbug is round and almost plump.
Adult bedbugs are about ¼” long. The immature bedbugs, called nymphs, are almost as small as the head of a pin. They are almost colorless, but after they get a blood meal, they turn rusty red.
The nymphs shed their skin several times as they develop into adult bedbugs. People may notice these cast-off skins, especially if there are a large number of bedbugs.
Like all insects, the bedbug’s body is made of three segments. The front segment is the head. The middle segment is the thorax. The segment in the back is the abdomen.
Bedbugs have compound eyes as many other insects do. Their antennae attach to the head near the eyes. Rather than seeing or hearing, scientists suspect that bedbugs sense a human host by detecting the body heat and the carbon dioxide that the host exhales.
Bedbugs have a mouth that is almost like a beak. It is perfectly suited for breaking the skin of a sleeping person. After breaking the skin, the bedbug inserts two small tubes into the host. One tube injects saliva. The saliva keeps the blood from clotting during the feeding. The other tube draws the blood into the bedbug’s mouth.
The bedbug’s thorax is the body segment that enables it to move. This is the segment where the bedbug’s legs are attached. The bedbug’s legs are long. It can walk and climb very well. Adult bedbugs only have stubs of wings, so they cannot fly.
People used to place pans of water under the legs of their bed. By doing this, they hoped to keep bedbugs from climbing onto the bed. The people discovered that the bedbugs could climb the wall and drop onto the bed from the ceiling.
The bedbug’s abdomen is the segment that contains its vital organs. As the bedbug feeds, blood often flows through its digestive system. Because of this, bedbugs often leave blood spots on the sheets and bedding when they feed. Bedbugs also leave dark fecal stains around the cracks and crevices where they hide.
These blood spots and stains are evidence that bedbugs have been active. Bedbugs produce a sweetish odor from glands on their abdomen. People who are sensitive to smells say that the odor is unpleasant, especially when there are a lot of bedbugs in the area.