Adult Bed Bug Guide

Are you aware of the differences between adult bed bugs and juvenile bed bugs? Let me start with the primary difference: adult bed bugs can reproduce, and juveniles cannot. Otherwise, they can be difficult to tell from one another.

Certain behaviors, however, can tip you off to whether adult bed bugs are reproducing in your home.

The reason I want to point out these differences for you is that recognizing whether you have adult or juvenile bed bugs can help you to know what stage an infestation may be at. If you know these signs of adult bed bug activity than you’ll be better prepared to take the right steps to remedy your pest problem. Keep reading to get all the information you need.


Adult Bed Bugs

CC Image courtesy of British Pest Control Association

When Do Bed Bugs Reach Maturity?

Bed bugs have relatively long life cycles for insects, but insects in general tend to live fairly short lives. The thing with bed bugs is that they continue to reproduce, and colonies have individuals of various ages, which is what makes it so difficult to get rid of them. Their total life cycle from egg to end of life is about six months or less.

Bed bugs reach maturity at around five weeks of age. Before that time, they go through five molts, losing the old exoskeleton as they make the changes to go from nymph to adult. That being said, in cool conditions they take longer to reach full maturity and may live a longer lifespan, up to a year, even without feeding.

Bed bug lymph - CC Image courtesy of louento.pix

Bed Bug Shells

Bed bug exoskeletons following a moult - CC Image courtesy of louento.pix

Older nymphs may look a lot like adult bed bugs, although they’re usually smaller. They are not, however, able to reproduce until they’ve had their fifth molt.

CC Image courtesy of British Pest Control Association

Molted skins

Molting is an essential part of the bed bug life cycle. It’s when the insect sheds its skin in order to grow to the next stage. In fact, finding molted skins is one of the best ways to know whether you have an active bed bug infestation in your home. Bed bugs have to feed on blood from a host in order to molt and move to the next stage of life.

CC Image courtesy of louento.pix

The skins are often shed in corners and crevices of the furniture where the pests come out to feed. That means the best places to look for them are in between cushions and joints on couches and armchairs, and around the corners and bottom edges of mattresses on beds. They’re also found often along baseboards, in the junctions between walls or ceilings, and on luggage or clothing items brought into the home from an infested location.

A molted bed bug skin looks like the shell of a bed bug when it’s alive. The shape and size are about the same as the living insect, but the color is translucent rather than the full color of the living bug.

Molting and adult bed bugs

One of the interesting things about adult bed bugs is that they do not molt. Once the insect reaches maturity, molting its exoskeleton is no longer required. The adult size is finite. However, where there are adult bed bugs there will be molted skins because they will be reproducing and growing their bed bug colony with more nymphs and juvenile bugs.

Once the infestation is mature, there will be many more young bed bugs than adults. At this point, you are much more likely to spot the molted skins than a living bug itself.

How Big Are Adult Bed Bugs?

Bed bugs are fairly tiny insects. Before feeding, they’re flat and about the size of an apple seed, usually 4.5 5o 5.5 millimeters, which is around one-fifth of an inch. The adult bugs do change shape and size somewhat after feeding on blood from a host. At that point, the body becomes more cylindrical rather than flat and oval.

Bed Bug Size

CC Image courtesy of British Pest Control Association

Their bodies literally fill up with the meal they take in. The bugs will flatten back to their unfed shape and size after a few days of digesting their meal.

CC Image courtesy of AFPMB

CC Image courtesy of AFPMB

What Color Are Adult Bed Bugs?

One way to tell the difference between bed bug nymphs and adult bed bugs is their color. While nymphs tend to be a light yellow to brown shade, adults are a rusty, red-brown color. The color darkens after the bug has fed on blood from a host. In fact, if the insect has eaten recently, it can look quite bright red with the fresh blood.

CC Image courtesy of British Pest Control Association

CC Image courtesy of AFPMB

How Often Do Adult Bed Bugs Feed?

Adult bed bugs feed by sucking blood from the skin of a host. Each feeding takes around five to ten minutes. They do this about once per week; however, the amount of time between feedings does vary. Adult bed bugs can go for months at a time without feeding, especially in cool weather.

How Many Eggs Do Bed Bugs Lay?

One of the biggest problems with bed bugs is that their populations rise so rapidly. This makes infestations difficult to get rid of because the bugs keep reproducing.

Female bed bugs lay between three and five eggs per day. Compared to other insects, bed bugs actually have a fairly long life, so females can lay around 500 eggs in a lifetime. Remember, that lifetime is less than a year. That’s a lot of new bugs in your home, and it means that you can develop an infestation from just one fertilized female bug.

Bed Bug Eggs

CC Image courtesy of AFPMB

Do Adult Bed Bug Bites Hurt?

Most people never notice a bite from an adult bed bug. There are multiple reasons for this.

First, bed bugs tend to feed when you are sleeping or otherwise still and distracted. The bite is so small that it’s unlikely you would feel it during sleep. Additionally, bed bug saliva, like that of several other biting insects, contains agents that numb the skin of the host. These two factors, combined, result in most people never knowing that they’ve been bitten until spots appear.

Marks from bed bug bites may not develop until many days after the actual bite occurrence. The bite spots on your skin usually do not hurt, but they can be itchy. Some people report that the bites become itchier the more times they have been bitten.

Bed Bug Bites

It is possible for the bite marks to start hurting if you scratch them. Scratching bug bites irritates the skin and may break it, letting in bacteria. If bacteria leads to a skin infection, you may have more pain, swelling, and redness around the bites.


Identifying whether the pests you have actually are bed bugs is an important step in getting an infestation under control. You can identify bed bugs by physical characteristics. Adult bed bugs, however, are hard to spot simply because they tend to stay hidden until they are ready to feed.

Bed bug bites are also not usually the best way to identify an infestation. Some people don’t develop visible bite marks from bed bugs, and the bites take a while to show up, so they could have been received while you were somewhere away from your home. Instead, look for signs of adult bed bugs reproducing, such as molted skins from their offspring.

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