Bed bugs, Cimex lectularius

Order: Hemiptera
Family: Cimicidae


These insects are found worldwide, however infestations in the US have been on the rise in recent decades. Like all true bugs, bed bugs have piercing/sucking mouthparts. Their size varies depending on life stage and feeding status. Adult bed bugs are about 7 mm (¼ inch) in length. Before feeding their bodies are brown, flat, and oval shaped; after feeding bed bugs become reddish brown and rounded like a balloon. The eggs are creamy white and around 1mm in length (about the size of a pinhead). This makes them very difficult to spot. After emerging, nymphs begin feeding on blood as they grow and develop through five instars (stages). The first instars are only about 1.5 mm long, while the last (fifth) instar can reach up to 5 mm in length.

Quick Facts

  • Bed bugs are parasitic insects that feed on human blood. Insects in this order are classified as “true bugs”, which includes around 40,000 species worldwide.
  • Currently there are no known diseases transmitted by bed bugs.
  • Bed bug bites usually appear in clusters. Bitten areas commonly develop inflammation several hours after bed bugs have stopped feeding. However, the bite marks alone cannot be used to verify an infestation.
  • Accurate identification is important when confirming bed bug infestations. Some insects in the same family (Cimicidae) resemble bed bugs and can also feed on human blood. See the full fact sheet (link below) for information on how to distinguish them from bed bugs.


bed bug infestation

Bed bug infestation on a box spring. Adults, nymphs and blood spots are visible. Image credit: Whitney Cranshaw, Colorado State University,

bed bug bites

Bed bug bites. Inflammation occurs about 3 hours after feeding. Bed bugs have needle-like mouthparts, which they use to pierce the skin and suck blood. Image credit: Whitney Cranshaw, Colorado State University,

bed bug eggs

Bed bug eggs. Image credit: USDA Forest Service – Coeur d’Alene Field Office,

bed bug eggs

Bed bug nymph (first instar) caught on a sticky trap. Image credit: Gary Alpert, Harvard University,

bed bug

Bed bug engorged after feeding on a blood meal. Image credit: Gary Alpert, Harvard University,

Life history and habits

Bed bugs undergo incomplete metamorphosis and have three life stages: egg, nymph, and adult. A single female can lay over 200 eggs during one reproductive period. Under favorable conditions, more than three generations can be produced in a single year. Bed bugs are nocturnal; they remain hidden during the day and come out to feed at night. Adults can survive up to 12 months without food, making them a very persistent pest even in the absence of a suitable host.


The best strategy for dealing with bed bugs is to prevent infestations in the first place. Avoid buying used furniture or picking up abandoned furniture. It is important to take precautions when traveling to avoid bringing home these unwelcome guests. For individuals who travel frequently, there is a greater chance of introducing bed bugs into the home. Whenever you travel, it is always a good idea to assess the bed and furniture in the hotel or guest room for signs of an infestation before unpacking and getting settled. Consider bringing a bright flashlight to help inspect small spaces and crevices and make spotting bed bugs easier.

When looking for bed bugs examine the headboard, bedding, mattress, and box springs. In hotels, the bedding is changed regularly so it should be removed for a full examination. Look for liquid feces on fabric or other hard surfaces, which appear as dark spots. Check for bed bugs and dark spots on the mattress by examining the rounded corners and mattress tag if one is still present. One common hiding place for bed bugs is in the box spring, especially the plastic guards on the corners. Even if there are no signs of bed bugs, it is still recommended that you place luggage, electronics, and clothing on a dresser, table, or bathroom away from the bed and any carpet.

When returning home from a trip, luggage should be unpacked outside of your home. Examine toiletries carefully for bed bugs. Place clothing in a garbage bag and use a twist tie to seal it. Take the bagged clothes directly into the laundry room or laundromat. After removing clothes from the bag, immediately wash them with detergent and discard the bag in a trashcan outside of the home. Remove the clothes you are wearing and wash immediately or place in the dryer for 30 minutes. Items that cannot be washed should be placed in the dryer for 30 minutes at medium-high heat.

There are luggage sprays and patches marketed as bed bug control agents. However, most bed bug populations are resistant to the active ingredient in these sprays. Therefore, the use of these sprays is not recommended.


Bed bugs cannot fly; introduction to new areas usually occurs by accidental human transportation. Given their size, bed bugs are inconspicuous when they cling to clothing and hitch a ride to new locations. The insects can also crawl to an adjacent space as their population grows at an infestation site. For example, it is possible to get bed bugs from neighbors in an apartment complex.

These insects remain hidden during the day. Some common hiding spots include crevices on or near the bed or in dresser drawers. These insects can even hide in the small crevices of an alarm clock or electrical outlets located near the infestation site. Most bed bugs in an infested room will be found within 4.6 m (15 feet) of a bed as they prefer to remain near their host.

It is important to treat minor infestations before they become more established or spread to other areas. Eradicating major infestations can be very costly and time consuming.

Non-chemical management

When a bed bug infestation is confirmed, all bedding should be washed and dried thoroughly with high heat to kill all life stages. All areas should be vacuumed thoroughly, especially carpeted areas near the bed and where the carpet meets the wall. The vacuum bag should be moved to the trash immediately after. Worn mattresses should be thrown away, or if the mattress is newer and in good condition, it can be wrapped in a plastic case. Keep the mattress in the cover for a year or longer to kill any remaining bed bugs. Any clutter should also be reduced, which will reduce the number of hiding places and makes chemical treatments more effective.

Chemical management

The non-chemical control methods highlighted above are helpful, but alone they are not likely to eradicate all bed bugs in a home. Insecticides should be applied to areas that can harbor bed bugs. It is extremely important to read all insecticide labels carefully, as some may exert a degree of toxicity toward humans. Therefore, avoid applying pesticides to areas in the bedroom unless the insecticide label says it is safe to do so.

Lastly, hiring an experienced exterminator is recommended as it can be difficult to treat all possible areas where bed bugs hide. Certified professionals will also have more pesticide options at their disposal, increasing the likelihood of eradicating the bed bug population.


Encyclopedia Britannica. (n.d.). Bedbug. Encyclopedia Britannica. Available

Environmental Protection Agency. 2022. Bed Bugs Appearance and Life Cycle. Environmental Protection Agency. Available

Ogg, B. (n.d.). Bed Bug Prevention. University of Nebraska Lincoln. Available

Ogg, B. 2010. Managing Bed Bugs. University of Nebraska Lincoln: Institute of Agriculture and Natural Resources. Available

Smithsonian Institution. (n.d.). 1996. True Bugs (Heteroptera). Smithsonian Institution. Available

CSU Extension Fact Sheet

Download or view the CSU Extension’s PDF fact sheet for your reference.