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University of Minnesota Extension

Bed bugs

Quick facts

  • Bed bugs are pests of people because they bite us and feed on our blood.
  • They hide and can be challenging to see.
  • They are great hitchhikers and can easily be moved.
  • If you have bed bugs, don’t panic, they can be eliminated.
  • It is very difficult to eliminate bed bugs yourself. It is best to contact a pest control service to control bed bugs.

The return of the bed bug

 Brownish adult bed bug without wings
Adult bed bug

Bed bugs (Cimex lectularius) were almost completely removed from North America due to mass treatments with highly toxic insecticides that are no longer in use.

Frequent travel, being good hitchhikers, improved treatment methods that target other insects without affecting bed bugs, and a lack of public awareness has led to a rise in the spread of bed bugs.

Importance of bed bugs

Bed bug on human skin before biting. The bug's body is clear with a speck of red in the center.
Bed bug before a meal

Bed bugs are parasites that feed on humans, using the blood to grow and reproduce. Bed bugs are also capable of feeding on animals, including dogs, cats, and other pets.

People can be bitten without realizing it. Bite reactions vary from no reaction to mild (a red spot) to severe (rash or hives).

  • Reactions caused by feeding might be mistaken for other problems such as biting insects, like fleas or mosquitoes, sensitization to detergents and soaps, and irritants (e.g. poison ivy).
  • It is not possible to verify bed bugs from only red skin lesions; finding bed bugs is the only way to confirm they are present.

Bed bugs are not known to transmit disease to people.

Bed bugs are found in many places, including homes, schools, retail facilities, office buildings, libraries and other public areas.

Bed bug on human skin with body full of blood.
Bed bug after a blood meal

Identifying bed bugs

Be sure you have bed bugs before trying to control them. The "Let’s Beat the Bed Bug" campaign at the University of Minnesota found that 76 percent of samples submitted for identification are not bed bugs.

  • Adult bed bugs are oval, flattened, brown and wingless insects approximately 1/4" to 3/8" long (5-9 mm). They are similar in appearance to a wood tick. 
  • After the bug has taken a blood meal its color changes from brown to purplish-red and it becomes larger and more cigar-shaped.
  • Young bed bugs resemble the adult in shape but are much smaller, 1/16" (1.6 mm), when they first hatch. They are nearly colorless except after feeding.

Contact an expert to help identify any suspected bed bug specimens.

Bat bugs and other bed bug relatives  

comparison of a bat bug to a bed bug with bed bug on top and bat bug on bottom
Bat bugs have longer hairs near their heads.

Bat bugs 

Another bed bug species that can be found in homes is the bat bug (Cimex adjunctus). They are reasonably common.

  • They can bite people but much less frequently.
  • Bat bugs look almost identical to bed bugs; they are identified by the longer hairs near the head.
  • Bat bugs live in attics and eaves associated with bats, so inspection and control measures must be expanded to include areas where bats may be found.

Other bed bugs

There are other species of bed bugs that may be found in Minnesota but are much less common.

  • The chimney swift bug (Cimexopsis nyctalis) and the swallow bug (Oeciacus vicarius) feed primarily on birds.
  • They are sometimes found in houses when host birds are nesting in the home (including the attic and eaves).
  • These species can also feed on humans if their normal hosts are absent.

Biology of bed bugs 

  • After mating, females lay white, oval eggs (1/16" long) into cracks and crevices.
  • An individual bed bug can lay 200 to 250 eggs in her lifetime.
  • The eggs hatch in 6 to 10 days.

Newly emerged nymphs seek a blood meal.

  • Bed bugs typically bite the head and neck but they will also bite bare arms, hands, and legs.
  • They usually live close to where people sleep, rest, or sit for long periods of time.
  • They are active at night and generally hide during the day.
  • Bed bugs feed for 2 to 5 minutes and then move quickly to a hiding spot.

Bed bugs need to feed at least once before each molt (when they shed their outer exoskeleton), although they could feed as often as once a day.

  • Immature nymphs molt five times  before reaching adulthood.
  • There may be three or more generations per year. All ages are found in a reproducing population.

Under normal circumstances adult bed bugs will live for about 2 to 4 months.

  • Young nymphs can survive without a blood meal for days up to several months.
  • Older nymphs and adults can survive longer without a blood meal, up to a year under very favorable conditions.

Signs that you have bed bugs

Look where you sleep

Bed bugs typically group together in out-of-the-way areas, although some bed bugs will live by themselves, away from the rest of an infestation. The best way to check for.an infestation is to look for bed bugs where you sleep or rest.

In bedrooms, look particularly on and around:

  • Box springs, mattresses, bed frames, tufts, folds and buttons on mattresses.
  • Furniture such as desks and chairs.
  • Behind wallpaper, clocks and pictures.
  • Cracks in wood floors and under the edge of carpet.
Bed bugs clustered under a bed frame
Bed bugs on a metal bed frame
Groups of brown bedbugs under a box spring
Bed bugs on the underside of a box spring
Brown bed bugs along the seam of a mattress.
Bed bugs along a mattress seam
Bed bugs grouped along the seam of a blue backpack
Bed bugs on a backpack

Be careful when you travel

The greatest chance of finding bed bugs is while you are traveling. It is a good habit to check your room whenever you stay in a hotel, motel or similar place.

Check your luggage where you typically set it down when you enter your home and where you store it after traveling.

While bed bugs are most commonly found in bedrooms, infestations can occur in other rooms including bathrooms, living rooms and laundry rooms.

Look for spots or smears 

Bed bugs will sometimes deposit fecal spots (digested blood) while they are feeding. These are seen as dark (dark reddish or brownish) spots or smears found on bed sheets, pillowcases and mattresses, or in nearby areas.

  • Dark blood spots on sheets and bedding may indicate bed bug feeding.
  • In severe infestations, bed bugs may be more noticeable.
  • A combination of bed bugs, cast skins (empty shells of bugs as they grow from one stage to the next) and fecal spots will be very obvious when closely seen.
Bed bugs, cast skins, and fecal spots can be seen in an infestation.
Bed bug nest

Inspect carefully

These insects are small (1/16" to 1/4") and very flat, so they can move into very tight corners and cracks. They have been found under picture frames between the glass and the frame.

Bed bugs can be found behind electrical outlets and other wall plates.

  • Inspect all areas closely and, if in doubt, contact a pest control service.
  • If you find a bed bug stop inspection and begin control activity.
  • Bed bugs will move from their hiding places once disturbed. All further inspections should be accompanied by control measures.

How to avoid bringing bed bugs into your home


How to get rid of bed bugs


Authors: Jeffrey Hahn and Stephen Kells, Extension entomologists

Reviewed in 2021

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