There’s truth to the saying “know your enemy.” The more you understand about bed bugs, their behavior, and their lives, the easier it will be to eradicate them.
Bed bugs progress through three main stages: egg, nymph, and adult. The eggs take 6 – 9 days to hatch. Bed bug nymphs progress through 5 phases, or instars, before they reach adulthood. Between each instar, they must molt and take one blood meal. Adult bed bugs may live for 3 to 9 months, laying up to 6 eggs per day.
This article will explore the complete life cycle of a bed bug. We’ll explain each life stage in detail, including how long it lasts and what a bug in this stage looks like. Finally, we’ll discuss how long bed bugs live for, and whether they can survive in hostile conditions.
What is the Bed Bug Life Cycle Timeline?
Before we get into the details of each life stage, let’s look at a quick overview of the timeline.
|Stage 1: Egg||Bed bug eggs can be found in dark, secluded spots around the home. They are tiny and white.||Eggs take 6 – 9 days to hatch.|
|Stage 2: Nymph||Juvenile bed bugs (too young to breed). Nymphs are 1.4 – 4mm long. They progress through 5 stages, called instars, before reaching adulthood.||Each instar lasts 5 – 8 days. In total, the nymph stage lasts around 35 – 40 days.|
|Stage 3: Adult||This is the final developmental stage. Bed bugs are at their largest (4 – 7 mm) and may reproduce during this stage.||Bed bugs may live for 3 to 10 months as adults.|
Let’s now examine each stage in more detail, starting with eggs.
1) The Egg Stage
The egg stage, as you might guess, is where it all begins. Bed bugs begin their development inside eggs, laid in quiet, dark, secluded spots around the home.
Particular favorite spots include tight crevices where the eggs aren’t likely to be disturbed.
- Joints and crevices in the bed frame or headboard
- Creases in the mattress, such as the piping along the edges
- Inside furniture, such as couches, nightstands, dressers, wardrobes, and vanities (particularly inside the wood joints, or underneath)
- Carpets and rugs, especially at the very edges of the room
- Cracks in walls and baseboards, including underneath flakes of chipped paint
- Inside electrical outlets and underneath light switches.
Bed bug eggs are sometimes laid in small clusters, but are often laid alone. After they are laid, bed bugs glue their eggs to the surface using a sticky secretion.
Nowhere is safe – eggs are so small that they could reasonably be anywhere. Eggs might be hiding on the backs of pictures hanging on the wall, in curtain folds, inside electronics such as computer keyboards, or even on stuffed animals. They may not all be in the bedroom, either – bed bugs may spend time anywhere that humans are present.
What Do Bed Bug Eggs Look Like?
It’s not impossible to see a bed bug egg with the naked eye, but you’d have to look quite hard to spot them.
Typical bed bug eggs are less than 1mm long. They are an elongated oval shape, like a piece of short-grain rice (though much smaller).
Bed bug eggs are a whitish color and slightly translucent. If you look hard enough, you may be able to see a small dark dot in one end.
How Long Do Bed Bug Eggs Take to Hatch?
On average, bed bugs spend about 6 to 9 days in the egg stage, under optimal conditions. For the most rapid development, bed bug eggs prefer temperatures above 70 degrees Fahrenheit.
If the temperature is lower, it may take several extra days before the eggs are ready to hatch.
How to Find Bed Bug Eggs
Finding and killing bed bug eggs before they hatch is one way to help keep your bed bug population down.
If you’re going on a hunt for bed bug eggs, you’ll need three things: a magnifying glass, a powerful flashlight, and a lot of luck.
Bed bug eggs are so small that they tend to be overlooked easily. Because they’re slightly translucent, they blend in well with any background that they’re laid on. And because bed bugs tend to lay their eggs in the most unlikely of places, and the tiniest gaps, it’s hard to find them all.
You’ll need to search every room in your house, and leave no stone unturned.
If you do find bed bug eggs, you might be wondering how to tell whether the eggs alive or have already hatched. Here’s what to look out for.
- Live bed bug eggs are whitish in color, plump, and not shriveled or wrinkled.
- Check to see if the tip of the egg (the cap) is intact. If it’s gone or the egg is opened, then the bug has already hatched.
- If you can see two small red dots near the end of the egg, this is an indicator that the egg is almost ready to hatch. The dots are the bed bug’s eyes.
2) The Nymph Stage
Once the bed bug hatches from the egg, it is classified as a nymph. “Nymph” is used to refer to bed bugs that have not yet reached adulthood. This is the second-longest stage of bed bug development.
The nymph stage is split into 5 separate phases, known as “instars.” To move on to the next instar, a bed bug nymph must do 2 things:
- Take one blood meal from a human host
- Molt (shed their exoskeleton).
Each instar is slightly bigger than the last, until the nymph grows into an adult.
What Does a Bed Bug Nymph Look Like?
Bed bug nymphs start very small (1.5 to 2mm long), and cream in color. Once they’ve fed, they appear bright red, as their bodies are so thin that you can see through to their stomach contents.
As the nymphs progress through each instar, they get slightly bigger and slightly darker in color.
The body shape of a bed bug nymph is identical to that of an adult bed bug, just smaller. They have a small head, to which two antennae are attached, and a small thorax. Their abdomens are large and oval, and they have six legs. After taking a meal, nymphs become more elongated and swollen.
How Long Does Each Instar Last?
The length of each instar depends on two variables:
- At optimum temperatures (above 70 but below 90 degrees Fahrenheit), nymphs can move, feed and grow more quickly.
- Availability of a human host. From the moment the nymph hatches from the egg (or sheds its skin), it will begin searching for a human to feed on. It can’t grow, molt or progress to the next instar unless it has taken a blood meal.
Once the nymph has fed, it will take around 5 days before it sheds its skin. If the nymph can feed within 24 hours of molting, each stage may only last 5 days in total. However, progress can be stalled by low temperatures and by a lack of food.
Assuming optimal conditions, the entire nymph stage – from hatching to becoming an adult – will last 35 to 40 days.
3) The Adult Stage
After reaching the 5th instar, a bed bug nymph will take one more blood meal and then molt once more. After it crawls out of its shed skin, it is officially an adult.
Once a bed bug has reached adulthood, it is fully grown, and will no longer shed its exoskeleton. However, it will continue to take blood meals from its human host, for the rest of its life.
Adult bed bugs will seek out a blood meal approximately once every 3-7 days. However, this does depend on the ambient temperature in the home.
A study by Medical and Veterinary Entomology found that at warmer temperatures (78 degrees Fahrenheit), bed bugs feed more frequently, around once every 2.5 days.
At colder temperatures, however, they may only feed once every 10 days, or even less often.
As well as drinking blood, adult bed bugs have two additional duties: mating, and laying eggs. Of course, it’s the female bed bugs that lay eggs. The males mate with as many females as they can.
What Do Adult Bed Bugs Look Like?
Adult bed bugs look a lot like apple seeds. They are approximately the same size – between 4.5mm and 7mm long. They are the same color as apple seeds – a deep mahogany brown, with hints of red.
Like their younger counterparts, adult bed bugs have six legs, two short antennae, and oval-shaped abdomens. Their bodies are very clearly segmented when viewed from above. This can help to distinguish them between other similar-looking bugs, such as spider beetles and carpet beetles.
The adults are the easiest bed bugs to spot, as they are the largest, and the darkest in color. However, they do tend to stay hidden in cracks and crevices around the home, especially during the daytime. At night, bed bugs will emerge from their hiding spots to feed.
How Do Bed Bugs Reproduce?
Bed bugs are sexual creatures, like humans. One female and one male bed bug must come together and mate to reproduce.
Male bed bugs possess a pointed sex organ called an aedeagus. This is located at the very tip of the abdomen. When a male bed bug seeks out a female, he will use his aedeagus to penetrate the female bed bug on the underside of her abdomen.
This process breaks the female’s exoskeleton, which is why bed bug copulation is called “traumatic insemination.” The ordeal results in an open wound which must heal for the female to survive.
The male’s sperm will then make contact with the female sex organ, called the mesospermalege. From there, it migrates to the ovaries, where it fertilizes the female’s eggs.
3 to 6 days later, the female will lay her eggs. She may lay them all in her harborage (where she spends most of her time), or she might lay them one by one, on her travels.
Can Bed Bugs Lay Eggs Without Mating?
Many types of life form, including several species of insect, can lay eggs without mating.
In asexual reproduction, the female of the species can lay eggs without having the eggs fertilized by a male. This creates the handy ability to reproduce quickly, without the need for a partner of the opposite sex.
Some sources claim that bed bugs can reproduce asexually. Fortunately (for us), this is a myth. Though asexual reproduction would inevitably help the bed bug species to survive, they haven’t yet evolved that ability. Bed bugs are strictly sexual reproducers: a female bed bug must mate with a male bed bug to lay eggs.
However, bed bugs may not begin to lay eggs until six days after mating has taken place. This means that it’s possible for a pregnant female bed bug to work her way into a different room, apartment or even a new home altogether before laying her eggs. Just because you may have only found one bed bug in your home, you could still be in for trouble.
How Long Do Bed Bugs Survive?
Now that you’re familiar with the bed bug life cycle, there’s probably one question on your mind: how long do bed bugs live for?
This question is not as straightforward as it may seem. The lifespan of an adult bed bug depends on several factors.
- Availability of a host to feed on
- The presence of pesticides in the environment
Aside from the above circumstances, a bed bug’s life could be cut short by other means, too. For example, you might roll over while you’re sleeping and inadvertently crush a bed bug to death. Traumatic insemination can also result in the death of the female, if she is mated with too many times, or the wound doesn’t properly heal.
In laboratory studies, it’s been found that adult bed bugs can live for up to 300 days – that’s almost 10 months.
However, the bed bugs in lab studies are raised in optimal conditions. The environmental temperature is strictly controlled, and they are provided with as much blood as they could want.
So, let’s look at the factors that could affect bed bugs in typical situations, and how they might influence their lifespan.
How Long Do Bed Bugs Live Without Feeding?
There have been many laboratory studies devoted to finding out how long bed bugs can live without food.
One study, conducted by the Department of Entomology at Virginia Tech, found that adult bed bugs can survive between 41.5 and 142.6 days (1.4 months and 4.7 months). That’s quite a long time.
It’s thought that bed bugs go into a hibernation-like state when starving, meaning that they use up less of their bodily resources, enabling them to survive for significantly longer.
But what about nymphs? As we’ve discussed, a bed bug nymph must take at least one blood meal before being able to molt, and progress to the next instar. The bed bug life cycle without food is the same as the normal life cycle – it just lasts a lot longer.
The same study found that without food, nymphs (up to and including the 4th instar) were able to survive between 13.6 and 131.9 days. The younger the nymph, the quicker they died without food.
Different studies invariably come up with different results. Some studies have found that bed bugs were able to survive for over a year without food. This could be due to differing laboratory conditions, or different strains of bed bugs from different areas.
One thing is clear: trying to “starve out” bed bugs isn’t a practical choice, unless you’re willing to stay in a hotel for a year.
Can Bed Bugs Survive Extreme Temperatures?
Bed bugs rely on the correct household temperatures to thrive, grow and breed.
Multiple studies have shown that bed bugs live the longest at temperatures between 70 and 80 degrees Fahrenheit. This is hugely convenient for bed bugs, as the majority of people set their home thermostats between 70 and 75 degrees.
Bed bugs can still survive to a reasonable degree above and below these temperatures, though they may not live as long.
It’s not a coincidence, either – bed bugs have evolved alongside humans for thousands of years. They have become adapted to living in the same environmental conditions as us.
High temperatures and low temperatures can both be deadly to bed bugs. Studies have demonstrated that bed bugs can’t survive temperatures above 140 degrees Fahrenheit, or below 0 degrees Fahrenheit.
Professional exterminators use this in their favor. Whole-house heat treatment has proven very effective at eradicating even the largest infestations of bed bugs. It’s the only sure-fire way of ensuring that no bed bugs or eggs survive.
Can Bed Bugs Survive Pesticide Treatment?
Pesticide treatment has been the go-to method of bed bug eradication for decades. To this day, most commercially sold bed bug killers contain insecticides such as pyrethroids and neonicotinoids.
However, according to several recent studies, most strains of bed bug have now developed a resistance to the most commonly used pesticides.
But how has this happened? They evolved the ability the way that any organism evolves: natural selection.
With every new generation of bed bugs, there’s a chance that some will be born with a genetic mutation allowing them to survive a pesticide treatment. When pesticides are used, only the resistant bugs survive. They then pass on this trait to their children, leading to an entire pesticide-resistant strain.
What About Desiccants?
There are still some bed bug killers that work. Desiccants like diatomaceous earth, for example, work by leaching moisture out of the bugs and dehydrating them. Bed bugs can’t develop a resistance to this, so they’re always a safe option to use.
That being said, desiccants alone can’t handle a large infestation. Only the bugs which are directly exposed to the treatment will be killed. The bugs that manage to escape and hide will survive, and start a new generation.
If you’re struggling to deal with bed bugs, contact a professional exterminator. They’ll be able to assess how bad the infestation is, and recommend an appropriate treatment, which will likely be a heat treatment. The longer that you leave the problem alone, the harder it will be to treat.