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Bed Bug Biology

 

Close up of an adult bed bug on the skin of a person's forearm

Bed bugs, Cimex lectularius, are small, wingless insects with flattened bodies. Their mouth parts are adapted to piercing skin, and they exist on a diet of human blood. They reproduce extremely rapidly: In ideal circumstances, a single gravid female bed bug can produce thousands of progeny in a single year.

During the day, bed bugs hide in cracks and crevices in the room, furnishings, mattresses, or other protected areas. At night, they emerge from hiding to feed on people's blood while they sleep, attracted by their body heat and the carbon dioxide that they exhale. Because of their secretive habits, it's not unusual to have a bed bug problem, but to never actually see a live bed bug.

The bed bug life cycle consists of five molts, each of which must be preceded by a blood meal. This means that all of the nymphal stages of bed bugs (commonly called "instars") bite and draw blood, not just the adults. You can find helpful information about identifying different stages of bed bugs here and here. You can also take a picture of "your" suspected bed bugs and request an ID on the Bedbugger Forum.

One thing to remember is that a bed bug that hasn't fed will keep searching for a host until it dies, which it eventually will if it can't find a meal. That's a pretty good motivation to find one, so bed bugs don't give up. They keep looking until they find a tasty human to feed on.

So if you live in a multiple dwelling and your next-door neighbor has a bed bug problem, and that person moves, the bed bugs may very well come over to your side of the wall. They're not picky. Your blood will satisfy your hunger just as much as your neighbor's did. Similarly, if you have bed bugs in one bedroom, moving to another bedroom won't solve your problem. The bed bugs will follow you. They might be slightly annoyed, but they will not be deterred.

Bed bugs reproduce using a process known as traumatic insemination. What this means is that the female has no orifice into which the male can insert his reproductive organ. Rather, the male actually pierces the female's body with his organ to inseminate her. Some females die of injuries sustained during insemination or from diseases caused by pathogens that infect the puncture site.

Assuming that a female survives insemination, she will start laying a few eggs every day. The eggs are tiny -- about the size of a speck of dust -- and have a sticky coating that helps them adhere to surfaces. This sticky coating also makes them hard to remove using a vacuum cleaner, which is why I recommend shampooing the carpeting as one of the preliminary steps of a bed bug treatment. The hot water and carpet shampoo loosen the glue and wash away the eggs.

Under ideal circumstances, bed bug eggs will hatch in about a week and reach maturity in about a month, passing through five molts to reach adulthood, each of which must be preceded by a blood meal. Obviously, this makes for an astronomical potential population growth rate. In addition, bed bugs can live for quite a long time without a meal. Adults and later-stage instars can survive for several months to more than a year at cool temperatures. Earlier stages can't survive quite as long without a meal, and the unfed survival time for all stages is shortened by higher temperatures.

On the bright side, at the time of this writing, bed bugs in North America are not believed to transmit diseases. You can read more about that here.

Reasons For the Increase in Bed Bug Infestations

For most of the 20th Century, bed bugs were considered to have been eradicated from the United States and many other developed nations. They were rarely encountered between the end of World War I and the mid 1990's. In fact, most professional exterminators working during those years had never even seen a bed bug, much less performed a bed bug treatment.

That all started to change around the early 1990's when pest control companies started receiving occasional calls for bed bug control. At first, many exterminators thought the callers were suffering from delusory parasitosis. But before long, we realized that they weren't. Bed bugs were indeed making a comeback. And by the time we watched the ball drop to ring in the 21st Century, pest control companies in major cities in the United States were literally swamped with bed bug calls.

Entomologists believe that there were two primary reasons for the resurgence of bed bugs in America. The first was a shift away from highly-volatile, broad-spectrum insecticide sprays that began in the 1980's. Less-toxic, species-specific bait products started replacing smelly, old-fashioned sprays for the treatment of pests like cockroaches and ants. That was a good thing in terms of reducing people's exposure to pesticides; but because these baits weren't at all effective against blood feeders like bed bugs, it is believed that they allowed bed bug populations to recover and thrive.

The second reason suggested for the rapid increase in bed bug infestations is simply that people travel more these days. Bed bugs were never eradicated from many other countries, so more travel to and from those countries means more bed bugs being brought back in clothing and luggage.

Unfortunately, whatever the reasons, the American pest control industry was ill-prepared for the resurgence of bed bugs. There were very few pest control technicians who had ever done even a single bed bug control job, and even fewer insecticides labeled for bed bug control. In addition, like most blood-feeding parasites, bed bugs are inherently difficult to kill. All of these factors (and others) contributed to the present state of affairs in which bed bugs have become the most prevalent parasitic pest in most American cities -- and one of the most expensive pests to treat, as well.

Why is Professional Bed Bug Control So Expensive?

Bed bug control is expensive because it is labor-intensive, requires highly-trained technicians (ideally working in pairs), and has a high failure rate. Pest control companies set their man-hour (person-hour?) labor rates for bed bug control higher than they do for other kinds of pest control work because they know that a higher percentage of bed bug treatments will require unpaid warranty callbacks. In fact, most companies simply assume that they won't get all the bed bugs the first time around and schedule multiple visits for every bed bug treatment.

The main reason why the callback rate for bed bug extermination is so high is because bed bugs are hard to treat. Unlike insects like cockroaches and ants, they never "handle" their food, so residual insecticides aren't as readily absorbed into their bodies. Some absorption occurs through the feet when the walk or through their skin when they hide in treated cracks and crevices; but because the potency of most residual insecticides drops rapidly after they're applied, if all the bed bugs aren't killed within the first few days after a treatment, chances are that the survivors will repopulate the infested room.

Even if all the adult and nymphal bed bugs are killed during the initial treatment, usually the eggs will not be. The only two treatment methods that kill eggs are heat and fumigation. The rest of the treatment methodologies either rely on using residual insecticides for the initial treatment in the hope that newly-hatched bed bugs will run into the insecticide and die, or scheduling a second treatment to kill them with non-residual methods such as contact insecticides or steam.

Another reason why bed bug treatment failure rates are so high is that many customers (especially landlords) shop for the lowest price when seeking bed bug control. There is no other endeavor in which the old adage "you get what you pay for" is truer than it is in bed bug control. Pairs of highly-trained, highly-skilled, highly-paid pest control technicians, with plenty of time to do their jobs and the best products and equipment, find bed bug control challenging. Poorly-trained, poorly-equipped, poorly-paid technicians, working against tight time constraints, find it impossible -- and that's exactly what you get when you choose the cheapest bed bug control company that you can find.

In apartments and condos, non-treatment of units adjacent to those with known bed bug problems is another reason why the failure rate is so high. Sometimes the landlord, condo board, or unit owner simply doesn't want to spend money to treat for bed bugs that they don't believe they have; and sometimes tenants in units adjacent to infested ones refuse to allow or cooperate with the treatments. The problem is that most of the time, at least a few bed bugs will migrate to the adjacent units (both horizontally and vertically) when a unit is treated; so not treating the adjacent units often results in those units becoming infested as some bed bugs survive and flee the treatments.

Even the homeowners or tenants in infested houses and apartments can't be counted on to properly prepare for a bed bug treatment. Without proper preparation, a bed bug treatment is doomed to failure. In fact, many pest control companies instruct technicians to walk away from a job (and usually bill the customer for a missed call) when the preparations haven't been carried out properly. The chances of success when a home has not been properly prepared for a bed bug treatment are so low that it's not even worth trying.

Finally, like most insects, bed bugs have the ability to develop resistance to insecticides. This is usually a selection process rather than an individual resistance process. In any population, there are likely to be a few individual insects that are less susceptible to a given family of insecticides. Those individuals are more likely to survive a treatment, and if their resistance is genetically linked, to pass it on to their offspring. Over the course of a few generations, the resistant bed bugs become the majority; and bed bug generations being as short as they are, that can happen quite quickly.

The DIY Bed Bug Control Option: Why to Try It, and Why Not To

When all is said and done, the only good reason to try DIY bed bug control is to try to save some money. I emphasize "try to" because as I said on the home page, your chances of success are less-than-wonderful. Highly-trained exterminators with decades of experience and all the latest and greatest tools and products have failure rates ranging from 15 percent to 35 percent for bed bug work. The failure rate for DIY bed bug control is much higher, and most people who try the DIY route wind up hiring a professional in the end anyway, thus increasing their total treatment cost.

Nonetheless, some do-it-yourselfers will succeed at bed bug control; so if you want to roll the dice, best of luck to you. If you use the advice in this site, your chances are better than most, so go ahead and gamble if you like. I wish you the best of luck.

Another good reason to try do-it-yourself bed bug control is because you really can't afford to hire a professional. If that's your situation, then I wish you extra special good luck because you really don't have money to waste. Be thorough and meticulous with your treatment to the point of obsession, and hopefully you'll solve your bed bug problem.

Now let's look at some reasons not to try DIY bed bug control:

1. Because you think it's safer. It isn't. The pesticides that you can buy over-the-counter are pretty much the same products that professionals use, except that most OTC products are pre-diluted, whereas professionals usually use concentrates that they mix on-site. The percentage of active ingredient in the finished product is usually the same.

In addition, pest control professionals are more precise with their applications and typically use less insecticide than most do-it-yourselfers. Insecticides cost them money. It does them no good to use more than necessary to achieve control. Furthermore, when you hire professional exterminators, they're the ones with the most exposure to chemicals. When you do it yourself, you are.

2. Because you want to do it "non-chemically." Unless you're using whole-house heat treatment (which is very effective when done properly, but which requires very expensive and specialized equipment), it's almost impossible to eradicate bed bugs completely non-chemically.

3. Because you have some home-brewed solution that you want to try. Aside from almost never being effective, some folk remedies for bed bug control are so dangerous that I'm not even going to mention them here (and I won't tell them to you if you e-mail me).

What it all boils down to is that bed bugs are very difficult insects to treat. Professionals find them challenging, and amateurs even more so. If you can afford it, you really should consider hiring a professional exterminator to solve your bed bug problem. But if you can't afford it (or if you just like challenges), then read on.