What Causes Bed Bugs?

Bedbug infestations can be extremely annoying and stressful to deal with. These pesky creatures can easily infest a house, multiplying quickly and occupying every nook and cranny. Aside from the physical annoyances, like bites, itchiness, and skin rash, bedbugs can also have a deleterious effect on a person’s mental state and psychological well being.

Most instances of bedbugs are caused by two kinds of parasitic insect: Cimex lectularius and Cimex hemipterus, both members of the larger Cimicidae family. Of the two, lectularius is the prime offender, constituting the majority of cases. Contrary to conception, bedbugs infestations are not caused by a lack of hygiene, but normally through the accidental physical transfer of bedbug specimens.

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Most cases of bedbugs are instigated by a handful of insect specimens being brought into a living space while clinging onto clothing or other belongings. Once inside of a house, they spread out and occupy as much space as possible, favoring tight enclosed spaces. Treating bed bugs can be hard because bedbugs can live and remain dormant for up to a year without feeding. As such, bedbugs are notoriously difficult to get rid of, and bedbug infestations often require multiple treatments for eradication. Bedbugs exist in every part of the globe and have been known by humans for millennia. Infestation rates have been increasing in the last 30 years which is believed to be caused by increasing amounts of human travel and resistance to pesticides.

Cimex lectularius: Description And Facts

Credit: WikiCommons CC BY-SA 2.0

Cimex lectularius is a small parasitic insect that ranges from 4mm-6mm in length. They have very flat, rust-colored bodies, with colors sometimes approaching purple. Like all insects, they have 3 main body segments: head thorax and abdomen. The abdomen is disproportionately large compared to the rest of the body. attached to the head is a pair of antennae used for probing the surrounding environment. Females are on average large than males and have rounder abdomens.

Lectularius are gregarious insects, like cockroaches, that occur in large quantities in close living conditions. In human residences, they prefer cracks and crevices in walls, furniture, carpets, wood paneling, and clothing. During the day they hide away, coming out at night to search for food. Bedbugs are considered ectoparasites, meaning that they live on the exterior of their hosts, feeding on their skin and nearby surroundings.

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Bedbugs are obligate blood eaters (hematophage). They have a specialized jaw meant for sawing the skin and sucking blood. the insect pierces the skin with a beak-like structure called the “rostrum.” Sawing motions of the mandible and maxilla open up a suitably sized blood vessel, freeing blood to flow into the insect’s mouth. Similar to a feeding mosquito, squishing a blood-filled bedbug will leave a red stain on the surface. Bedbugs are small and have tiny mouthparts, so most of the time they can feed without being noticed by their larger host. Their saliva contains an anticoagulant chemical that allows them to suck blood easier. Even though they come into direct contact with their host’s blood, bedbugs are not known to transmit any infectious diseases like MRSA, hepatitis, or malaria.

Bedbugs go through 5 distinct life stages that all require a supply of blood for proper development. Without blood, bedbugs will not develop properly.  Bedbugs can go for very long periods of time without feeding, making treating infestations difficult as they can lie dormant for a long time before emerging again. Bedbugs find prey by using their antennae as a kind of dowsing rod, searching for heat, moisture, and carbon dioxide levels to identify prey.

Reproduction for bedbugs is much like that for other insects. Copulation is an unceremonious affair during which males will pierce the female’s abdomen with their genitals to directly deposit their sperm. Males will often mistake larger males for females and attempt to copulate.

After copulation and fertilization, the female lays a large brood of eggs. Females on average lay a total of 300 eggs over their lifetime. Egss are very small but white and visible to the naked eye if looked at closely. Bedbugs breed continuously, so a small infestation can quickly get out of control due to rapid reproduction.

Signs Of A Bedbug Infestation

The most obvious sign of a bedbugs infestation is visible bite marks on the skin. Bedbugs tend to like mattresses, so at night they will creep out of the inside of the mattress and feed on sleeping humans. bedbugs bites normally manifest as tiny marks on the skin, though in some cases can form raised patterns of irritated skin and skin rash. In some cases, the wounds will bleed as a result of anticoagulants in the bug’s saliva. Most commonly, bedbugs bit on areas of the body with a large surface area; arms, shoulders, legs, and back. Some people have moderate to severe allergic skin reactions to bedbug bites, causing raised irritated patches of skin. bedbugs bites can be confused for other skin conditions like eczema or psoriasis.

Bedbug bites manifest as small macular spots on the skin. Credit: Louento via Flickr CC BY-ND 2.0

In addition to bites, other physical symptoms include general allergies from the bites, anemia from blood being sucked and inability to sleep due to discomfort and itching. People can also identify physical symptoms of a bedbug infestation on their pets. Large amounts of bedbugs are said to have a pungent, sweet odor that dogs can be trained to identify.

Bedbugs are very small but are visible to the naked eye if examined close enough. As such, visual inspection can determine if you have an infestation. Small blood marks on bed sheets and other furniture can indicate spots where a full bedbug was crushed and their eggs look like tiny white globules. Bedbugs prefer enclosed spaces away from light, like inside walls, clothes, luggage, mattresses; even electrical sockets and nearby electrical devices.

Bedbugs infestations have been noted for their unique psychological effects as well. Bedbug infestations have been linked with bouts of paranoia, insomnia, and general psychological distress. Even in cases where patients were not aware of their infestations, they can still show problems sleeping and general anxiety. Patients who are aware of their infestations can develop severe anxiety and stress, and even develop paranoid delusions about bedbugs. In a few reported cases, the psychological toll from bedbugs infestations has led a few people to commit suicide.

Infestation Treatment

Treating a bedbug infestation can be an arduous affair as they are difficult to get rid of. In addition to occupying hard to reach areas and small crevices, bedbugs can go 12 to 15 months without feeding, making it impractical to starve them out. Most treatments involve vacating the premises and thoroughly vacuuming and treating the affected surfaces with pesticides. Their hardiness makes bedbugs difficult to remove with a single treatment, and there is evidence that bedbugs have been developing pesticide resistance.

Some treatments involve heating infested rooms to high temperatures to kill the insects. By the same token, infested clothes can normally be treated by a thorough cleaning and drying on high heat. Bedbug eggs die on contact when exposed to temperatures higher than 180 degrees, and temperatures as low as 120 can outright kill adult specimens. It is recommended that one find the help of an expert to deal with an active infestation as treatments can be time-consuming and complex.

Preventative treatments include taking precautions and regular cleaning of potential infestation spots. Regular cleaning and vacuuming of household fabrics will loose and eggs and kill any hidden adult specimens. It is also recommended to thoroughly check all clothing before coming inside, especially if you have been near infested areas. Once bedbugs have set in, they can be very difficult to remove, so the most effective treatment is to avoid them in the first place.

History Of Bedbugs

The first written records that refer to bedbugs date back to at least ancient Greece. The Roman historian Pliny the Elder claimed that bedbugs have healing properties and could treat snake bites and ear infections. Various texts through the middle ages in Europe mention bedbugs, most often in the context of infestation in urban areas. Historical treatments for removing bedbugs included black pepper, eucalyptus leaves, certain kinds of berries, and in some cases other predatory insects. In the 19th century, one popular remedy involved fumigating rooms with peat fires.

The number of bedbugs infestation in the West took a noticeable uptick in the early 20th century, most likely a result of the advent of electric heating. Electrically heated homes stayed warm all year, allowing bedbugs to live and reproduce year round. Before the 1950s, it is estimated that 30% of US households had bedbugs.

Bedbug infestations have also seemed to take another uptick since the 1980s. The causes of this most recent uptick in infestations are not well known, though many epidemiologists cite pesticide resistance, increased rates of international travel, and more instances of trading secondhand furniture. Data on bedbug infestations are difficult to come by as they are not easily identifiable and not talked about much due to social stigma.

About The Author

Alex is a graduate of UMSL with his MA in philosophy, with an area of concentration in the history and philosophy of science. When he isn't nerdily stalking the internet for science news, he enjoys tabletop RPGs and making really obscure TV references.