National Pesticide Information Center



Bed Bug Biology and Behavior

Bed bugs are stow-a-ways. They enter homes by hiding in the cracks and crevices of incoming luggage, furniture, clothing, pillows, boxes and other objects. Bed bugs feed on human blood. Their presence has little to do with the cleanliness of the home, although clutter can provide hiding spaces for bed bugs and make them difficult to control. Once bed bugs are established, they rapidly reproduce and spread from room to room.


  • Bed bugs are found living with humans worldwide.
  • Bed bugs have five immature life stages before becoming adults (see image above). In order to shed their “skin” (molt) and grow to the next life stage, bed bugs must have a blood meal. In ideal conditions it takes about 37 days from when eggs are laid until the bed bugs become adults.
  • Adult bed bugs are the size of an apple seed, while eggs are the size of the period at the end of this sentence.
  • Bed bugs usually feed every 3-7 days.
  • An immature bed bug or a male bed bug introduced into a home will not start an infestation, but one pregnant female can quickly reproduce. Preventing introduction is key.
  • Females lay eggs anywhere they wander, either separately or in a group. Eggs can take 6-10 days to hatch. For this reason, repeated and persistent monitoring is key when trying to control bed bugs.
  • Bed bugs can survive for months without feeding, so they may be present in vacant, clean homes when new tenants unpack.
  • A bed bug can survive for up to three months without feeding at room temperature. At cold temperatures they can survive much longer without feeding.
  • It is usually drying out, rather than starving, that kills isolated bed bugs. If the moisture in the air is low, they will dry out much faster.
  • Bed bugs can carry diseases within their bodies, but transmission to humans has not been found.
  • Populations of bed bugs across the country have been found to be resistant to many common pesticides. Control requires an Integrated Pest Management approach.


  • Bed bugs hide during the day, and typically feed at night.
  • Bed bugs hide near areas where people rest for long periods of time, mostly on and around the bed. Couches, wheelchairs, and recliners are also common hiding places.
  • Bed bugs like to hide in tight areas, such as cracks, crevices, under mattress tags, in box springs, and any place dark and sheltered. In these hiding places you can find eggs, all ages of bed bugs, shed “skins” (which look like empty bed bug bodies), and dark spots or stains, which are the dried droppings from the bugs.
  • Bed bugs feed when their food source (host) is sleeping, usually at night. It takes 3-10 minutes for a bed bug to feed, but the bite is painless so people don’t know it’s happening.
  • Reactions to bed bug bites vary widely, and one third of people may show no reaction at all.
  • Bed bugs can be found on buses, on subways, in taxis, in movie theaters, in libraries and many other areas.
  • Large infestations and disturbances such as pesticide applications can cause bed bugs to spread to other areas of the home, or to neighboring apartments.

The National Pesticide Information Center (NPIC) received hundreds of calls last year from all over the country about bed bugs. If you have questions about this, or any pesticide-related topic, please call NPIC at 1-800-858-7378 (8:00am - 12:00pm PST), or email at npic@ace.orst.edu.

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Last updated December 23, 2015