How Long Does it Take For a Bed Bug Infestation to Show?

Written by: A O’Neill, Licensed Pest Control Professional

How Long Does it Take for Bed Bugs to Become an Infestation?

Bed bugs focus on two things for survival: feeding and breeding. The feeding part is taken care of if they have constant access to blood, preferably human blood, which is needed regularly so the female adult can reproduce.

The female will lay roughly 5 eggs a day for 10 days after feeding and mating. After that, she will feed again, and the egg-laying cycle will repeat after each blood meal.

The eggs hatch in 7-10 days and the nymphs reach adulthood in around 5 weeks. Once they mature, they will mate and keep reproducing as long as they have regular access to blood. You will then have a growing infestation that will start to get out of hand if not treated.

And, as if that’s not bad enough, the female can mate with her male offspring once they become adults.

How Does a Bed Bug Infestation Start?

Despite all the media coverage on their resurgence, many people still do not realize how a bed bug infestation can start in their homes.

Bed bugs can be found wherever people gather or spend periods of time. And travel is the number one way we bring these parasites into our homes.

I always advise checking your hotel room and carry out an inspection of the bed when you enter. If they are in the bed then they can soon be hiding in your bags and suitcases and traveling back with you.

There are other ways they can get into your home, such as on used furniture, from public transportation, or even from having a friend stay over.

You can read more here about the other ways you get bed bugs in the first place and how to prevent them.

By bringing just one pregnant female bed bug into your home is enough to start an infestation.      

How Long Does it Take for Bed Bugs to Multiply?

As mentioned above, the female bed bug lays approximately 5 eggs a day (various studies have differing amounts, but it’s around this figure) and between 200-500 during her life cycle, but is more likely 200-250.

These eggs hatch in 7-10 days (7 days under ideal conditions) and are so tiny and translucent white that they are very difficult to see.

A newly emerged nymph (baby bed bug) will seek out a blood meal and feed. The nymphs molt (shed their exoskeletons) five times before they reach adulthood.

However, they must have a blood meal before each molt can take place.

The nymphs can reach adulthood in as little as 21 days under favorable conditions of temperatures between 70-80ºF (21-27ºC) and constant access to a blood meal, but it more realistically takes around 5 weeks to reach maturity, and this is when you’re likely to see the infestation start to show.

However long it takes, the fact is that a female bed bug can lay eggs every day for 10 days if she has a mate and a blood meal.

So in 10 days, a single female bed bug will lay approximately 50 eggs. Not a nice thought!

There is another problem though, and that is there usually isn’t just one bed bug, so multiply the 50 eggs by 2 or 10 or more, and this now becomes worrying when you think of how many eggs there can be in just 10 days.

Although bed bugs do not reproduce as quickly as other pests and their infestations take time to develop, this does give you an idea of how long it takes bed bugs to multiply and how quickly an infestation can significantly grow within one month and beyond once the eggs have hatched.

Can You Have Bed Bugs and Not Know it?

Yes, you can have bed bugs and not realize you have them especially at the beginning of an infestation because of their ability to hide during the day and come out to feed at night when you sleep. 

In fact, an analysis of over 2,000 low-income apartments in New Jersey were examined for bed bugs in a Rutgers study.  Inspections found that 291 of the apartments had bed bugs, of which 49 percent of the residents had no idea they had bed bugs.^[1]

Unless you are not reacting to the bites or not noticing any signs of them, then it is possible they can go undetected to start with.  

How Do You Know How Bad Your Bed Bug Infestation Is?

It’s not uncommon to be unaware you have a bed bug problem in the beginning, as they are experts at hiding and mostly come out at night to feed. Perhaps you are not reacting to the bites, or you assume the bites are from a mosquito or other insect.

Whatever the scenario, the longer the infestation goes undetected, the harder it is to get rid of and the more expensive it becomes to treat.

It also increases the chances of the infestation spreading to other rooms or nearby apartments.

Bed Bug Infestation Levels

Bed bug infestation levels range from mild, to moderate and then to heavy.

There are key warning signs to look for in a mild infestation. If you have to go looking for evidence before you spot any, then a light infestation will be easier to treat, and you may want to do your own bed bug control.

In a mild infestation physical signs of bed bugs can be found when cleaning and removing bedding, by looking for:

• Bed bug(s) which you may not find when the infestation is still in the early stages.
  
• Rusty or dark red stains on the mattress or sheets produced when bed bugs have been crushed.
  
• Tiny black spots (about this size: •) that look like a marker pen has bled into the fabric. This is actually bed bug feces.
  
• Eggs and/or eggshells, that are a translucent-white color and are tiny (about 1mm). These are easily missed as they are so small and well hidden.

Moderate to heavy infestations will be far more obvious as can be seen in the photo above of just one corner of a box spring. You can see other photos of heavy infestations here.

In moderate to heavy infestations, you’ll notice some of the following:

• A considerable number of live adults and nymphs will be seen not just on the bed but crawling on walls, baseboards, etc. They will be visible in cracks and crevices in the walls, bed frame, behind picture frames, and other areas which are listed here.
  
• You’ll see bed bugs during the day as they are hungry and their harborage areas have become overcrowded, so they are infesting other areas of the room.
  
• Hatched and unhatched eggs can be seen along mattress seams, in folds of the mattress, box spring, and nearby furniture. If you sleep on your couch, then they can also be found hiding in there.
  
• Lots of dark fecal stains on the mattress, box spring, and other material furnishings.
  
• In a heavily infested room, you may smell the unpleasant sweet-musty odor that is likened to berries or coriander.
  
• Cast/shed skins are visible, especially on the bed. As the bed bugs are continuously producing offspring, there is an increasing build-up of shed skins mainly in harborage areas.

Can Bed Bugs Ever Go Away?

Can a bed bug infestation go away on its own? No! These blood-sucking parasites are not seasonal so they will not die out or go away by themselves as long as they have access to your blood.  

Treatment is vital to get rid of them, and it has to be done thoroughly as you don’t want even one pregnant female bed bug or any eggs to survive.

Having to deal with bed bug bites is bad enough, but it’s the emotional trauma from having these pests that can have a long-term negative impact on your mental health.  So it’s important to eradicate them as soon as possible.

Commitment and effort will be needed if you going to treat them yourself so take steps to limit their harborage areas by removing all clutter from under the beds and in the room.

Put bed bug proof encasements on your mattress, box spring, and pillows, and install interceptor traps under the legs of the beds and furniture. 

If your budget allows, then leave it to a pest control professional who knows exactly where to look for them and what treatments will be needed to eliminate them. 

Make sure you choose a reputable one, and this will guide you on how to choose the right pest control company.

[1] https://academic.oup.com/jme/article/53/3/639/222243

Related:

Interceptor traps for bed bugs
Pictures of bed bugs
What should you not do if you have bed bugs?