How to Identify Bedbugs and Distinguish Them From Other Pests
Common bedbugs (Cimex lectularius) are terrible pests. They feed on human blood, mostly at night, leaving itchy, red bites. But before you hit the roof and reach for the bug spray, make sure that it's really a bedbug you're looking at.
Unfortunately, my wisdom about these creatures comes from first-hand experience. While performing research in a bedbug-infested area, I learned a lot while we searched for bugs.
There are other bugs that resemble bed bugs. You will find more about bugs that look like bedbugs (but aren't) further on. The photographs in this article are meant to be a useful learning tool to help you identify your mystery bug.
What Do Bedbugs Look Like?
Bedbugs are strange little creatures. They are hard to see, as they move so quickly, but learning to identify them and how to distinguish between them and other household pests can save you time and money, not to mention prevent worry and stress.
Adult bedbugs are:
- light brown to reddish-brown (but may appear black, depending on the lighting),
- tiny, flat, and oval-shaped,
- about 0.15 inch (4–5 mm) in diameter,
- six-legged with two antennae,
- and segmented, with tiny hairs that make them looked striped.
What color are bedbugs?
Baby bedbugs (nymphs) are translucent and look white or very light brown. After they eat they become bright red, fading to brown over time, and finally to opaque black. Adult bedbugs are brown or reddish-brown.
What do bedbugs eat?
Blood. Blood changes the bedbug's color as the bug digests it. A bedbug's back looks flat if they haven't eaten. It looks raised after eating. Bedbugs seem to prefer human blood to animal blood. It's possible that fur acts as a deterrent.
Do bedbugs have a hard shell?
Like all insects, a bedbug's skeleton is on the outside of its body (exoskeleton). They molt, or shed their skeletal outsides, as they grow and the shells they leave behind are called casings.
Why are they called bedbugs?
They come out at night and are attracted to the carbon dioxide that people exhale while sleeping. Because they feed on blood, they crawl around the bed until they find the source of the carbon dioxide. Then they bite.
Signs of Bedbugs
- Casings or shells. Bedbugs shed their exoskeletons as they grow, leaving behind a dry, hollow casing, which looks like the bedbug, but without a body inside. They are small, only about 1/16 inch long. Look around your bed, near the mattress seam, or behind the headboard.
- Musty smell. Bedbugs smell like wet, moldy clothes or shoes. Some say the smell is like coriander. At higher concentrations, the smell is very unpleasant, like the odor a stink bug emits. The smell is stronger after a bug is killed.
- Blood stains on your pillowcase or sheets. Bedbugs feed on human blood so if the bug is squished after it has fed, there will be a spot of blood left behind.
- Dark, rust-colored spots on bedding or nearby walls. These spots could be bedbug excrement.
Look for Them Where They Hide
Bedbugs may hide under a mattress, around the bed frame, under rubber moldings, in shoes, behind clocks, frames, and metal brackets that attach shelves to walls, and on top of box springs.
How to Identify Bedbugs
It's important to know how a bedbug's appearance changes over the course of its life, between feedings, and due to genetic variation.
- Bedbug eggs look like small grains of rice.
- Adult bedbugs are the shape and size of an apple seed.
- A bedbug that is flatter is likely to head for a meal soon. If you squish it, there should be dark red, pasty goo. This is the digested blood which is now feces. Bedbug feces and cast skins are features of a bedbug infestation.
- Bedbugs are creepers that love to hang out together. In heavy infestations, it is not uncommon to find large groups of 10, 20, or more huddled together.
- A squished bedbug gives off a lingering, musty smell.
- While bedbugs do have vestigial wings, these wings don't work so bedbugs cannot fly. They also cannot jump. Bedbugs move by crawling. They move fast, about 3–4 feet per minute, which is fast when you think about how small they are.
How to catch a bedbug so you can identify it.
Try setting a trap. My favorite is Buggy Bed because it uses special ingredients that mimic carbon dioxide. This leads the bedbugs to the trap (and away from you.) The Buggy Bed trap uses an enclosed bait-and-trap system. Put one under your mattress, near where your head would be.
Stages of a Bedbug's Life
- Bedbug eggs hatch about after two weeks. The nymph then begins feeding right away. Bedbugs typically feed every 10 days and then molt, or shed their skin.
- Nymphs molt five times before reaching maturity (see nymph stages in chart above).
- Adult bedbugs typically live from four to six months. It is possible, however, for them to live longer under the right conditions.
Bedbugs look very different at different ages. For example, in the egg and early nymph phases, they can be difficult to see because they are whitish, unless they have started a meal. Then in their adult phase, they may be larger and a different color.
While young, the brown/red/black color signifies that the bug has had a blood meal. As a bedbug grows, it sheds its skin which is referred to as a cast. The human blood it eats is the energy source it needs to build a new, stronger skin.
As they grow older, their bodies become darker. Some people think that bedbugs are black. Don't be surprised when people have a difference of opinion on the whole color matter.
Factors that determine the appearance of bedbugs:
- A meal satisfies an adult and or baby bedbug for around two weeks.
- Bugs try to eat until their back is fully rounded.
- Bedbugs are at peak activity between 2 a.m. and dawn.
What Do Bedbug Eggs Look Like?
Bugs That Look Like Bedbugs (But Aren't)
There are bugs that look a lot like bedbugs, but they aren't.
- Spider beetles are oval-shaped and dark brown, but they don't feed on human blood.
- Baby cockroaches resemble bedbugs but are more cylindrical. They eat leftover human food, not blood.
- Booklice look like baby bedbugs. They are white and can be found behind wallpaper. They feed on mold and fungus, not blood.
- Carpet beetles are small, round, and brown but have distinct wings.
Can Dogs Smell Bedbugs?
Yes, a study in the American Journal of Tropical Medicine and Hygiene found that dogs could be trained to detect live bedbugs and eggs and to distinguish bedbugs from other urban insects. The dogs use their sensitive sense of smell to sniff out the pheromones that bed bugs emit.
This could be helpful information in situations where bedbugs are suspected by cannot be seen.
Professional or DIY Bedbug Removal?
Bedbugs are invasive and can live under the harshest of temperatures. A temperature of 113° F (45° C) will kill a bedbug in 15 minutes and an egg in an hour.
It is essential to spray poison thoroughly. If you do not feel comfortable with spraying, then you should call a professional. If you do it yourself, make sure to read all of the instructions on the pesticide container carefully. Then, read them again, and carefully! Be aware of the pesticide laws in your state and the rules set by the Environmental Protection Agency.
Be extra careful with pesticides!
Misusing pesticides can be dangerous. People have the tendency to use too much concentrate when mixing pesticide. If you choose to use chemicals, it is not a bad idea to print up a list of potential side effects. Also, research the chemicals and whether they are safe to use in your home. If you are a renter, DO NOT try to solve this issue yourself. Call your landlord.
How to Choose a Bedbug Exterminator
If these pictures are familiar I urge you to seek professional help. Specifically, look for a company that understands how feeding changes a bedbug's appearance. Exterminators should understand how important proper identification impacts successful extermination.
If you are going to invest in a professional, don't go with a cheap exterminator who does not know what they are doing. The result of using inexperienced exterminators is having to call them out repeatedly. This could cost you thousands of dollars. In the end, cheap exterminators are going to cost you more than the experts.
Look for a conditional warranty. This way the exterminators will come back until your problem is gone if you meet certain requirements, such as placing mattress covers on all mattresses.
- Orkin, the leading bedbug exterminator, goes so far as to explain that there are many different species of bedbugs.
- Terminix is another great option. They offer a lot of specials and often will give a free inspection and quote.
Whichever you choose, do your research before making a decision.
Wear Gloves Before Squishing
While bedbugs are not known to spread disease, for sanitary reasons you may want to wear gloves and use paper towels before squishing a bedbug.
Here are Some Squished Bed Bugs
How to Tell Whether Spray Is Killing Bedbugs
The photo above was taken one day after a spray. That is a great sign that the spray is working. There were still some living bedbugs in the area, however. I noticed that the living bedbugs would pick up the dead ones and hide under them, so even if you find a pile that looks like this one you shouldn't assume that all the bugs are dead.
A second spray may also be necessary, within two weeks or so, to make sure all of the eggs are dead.
How to Prevent Bedbugs
More than one expert I interviewed recommended using a high-quality mattress cover to keep bedbugs from settling on a bed.
Mattress cover recommendation
Several experts recommend Sleep Defense System. They have secure zippers and are machine washable (a must). Many other mattress covers are made of plastic, which means they will melt when you put them in the dryer. Be careful to choose a cover that can be washed.
Sleep Defense covers also use a pocketed zipper system. Once the cover is zipped, the zipper gets tucked under a cloth flap. This secures the zipper and keeps any remaining bugs on the mattress or box spring from escaping.
- "Types of Bed Bugs". Orkin. N.p., n.d. Web. 28 May 2012
- "Ohio State University Extension fact sheet: Entomology, Bed Bugs". OSU. N.p., n.d. Web. 28 May 2012.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Where do bed bugs bite you when you are asleep?
Bed bugs will bite you anyplace on your body while you are asleep. However, the most common place to be bitten by a bedbug is near the head and upper torso. The reason for this is because they can sense the carbon dioxide that you exhale. When you breathe out, about 5% of the gas is carbon dioxide. Even at this small amount, bed bugs can use it as a way to figure out where you are.
That might be the first place you notice bites, but deep bed bug infestations usually result in bites all over the body. In some cases, the bed bug is most likely to bite the closest part of the body to its nest. If bed bugs are nesting near the feet, you might notice the bites on your legs. Just because bed bugs are most likely to bite you closer to your head, don't discount bites in other places in your body.Helpful 29
Can you kill bed bugs with lower heat over a long period of time?
This is a good question. There is a degree of heat over time when it comes to killing bed bugs with heat. Bed bugs have a thermal death point of between 120 and 180 degrees fahrenheit. At that temperature, the higher the heath the quicker bed bugs die. However, temperatures below the thermal death point are not likely to kill bed bugs at any temperature. So yes, you can kill bed bugs with a lower heat over time IF the temperature falls within the thermal death point of bed bugs.Helpful 17
How can I find out what kind of bug I killed?
Engaging in insect classification may help you find out what kind of bug you killed. Spiders and insects are in a group called Arthropoda. Insect taxonomic charts can be used to help narrow down a bugs classification. Following taxonomic guides or charts is how to identify a bug yourself. You can find them online, in bookstores, and often at the library.Helpful 16
Are bed bugs eggs grey once they are dead?
Once bed bug eggs are dead they may dry out and change in color. They are normally, white or near white. A change in egg color may suggest that the bed bug is dead. However, this is not always the case. There are other factors to egg color classification, such as bug genetics.Helpful 14
Do bed bugs jump?
Bed bugs can not jump. Their bodies and legs make it physically impossible for a bed bug to mechanically propel themselves through the air. They can no hop, nor can they fly. Instead, they use their 6 legs to crawl, and even run. Most people could out run a bed bug though, if they were in a race.Helpful 14
© 2012 Melody Trent