Genera and species
The common bedbug (Cimex lectularius) is the best adapted to human environments. It is found in temperate climates throughout the world and has been known since ancient times.
Other species include Cimex hemipterus, found in tropical regions (including Florida), which also infests poultry and bats, and Leptocimex boueti, found in the tropics of West Africa and South America, which infests bats and humans. Cimex pilosellus and C. pipistrella primarily infest bats, while Haematosiphon inodora, a species of North America, primarily infests poultry.
Oeciacus, while not strictly a bedbug, is a closely related genus primarily affecting birds.
Adult bedbugs are reddish brown, flattened, oval, and wingless, with microscopic hairs that give them a banded appearance. A common misconception is that they are not visible to the naked eye, but adults grow to 4 to 5 mm (one-eighth to three-sixteenths of an inch) in length and do not move quickly enough to escape the notice of an attentive observer. Newly hatched nymphs are translucent and lighter in color and continue to become browner and molt as they reach maturity.c When it comes to size, they are often compared to lentils or appleseeds.
Bedbugs are generally active only at night, with a peak attack period about an hour before dawn, though given the opportunity, they may attempt to feed at other times of day. Attracted by warmth and the presence of carbon dioxide, the bug pierces the skin of its host with two hollow tubes. With one tube it injects its saliva, which contains anticoagulants and anesthetics, with the other it withdraws the blood of its host. After feeding for about five minutes, the bug returns to its hiding place. The bites cannot usually be felt until some minutes or hours later, as a dermatological reaction to the injected agents. Although bedbugs can live for up to 18 months without feeding, they typically seek blood every five to ten days.
Bedbugs are often erroneously associated with filth. They are attracted by exhaled carbon dioxide, not by dirt, and they feed on blood, not waste, so cleanliness is no protection from bedbugs.
While bedbugs have been known to harbor pathogens in their bodies, including plague and hepatitis B, they have not been linked to the transmission of any disease and are not regarded as a medical threat, however, some individual can get skin infections from scratching bites, and some people do get reactions to the bites. While bedbugs are not regarded as a vector of transmissible diseases, they are a serious stressor and will create a lot of alarm and distress.
Female bedbugs can lay up to five eggs in a day and 500 during a lifetime. The eggs are barely visible to the naked eye and are a milky white tone in color.
A few bedbug species make use of a mating plug, secreted by the male upon withdrawal after copulation, effectively gluing shut the vaginal opening of the female against later males. Among such species, some have further developed stabbing rape, where the male impales the female via her abdomen, thus circumventing a mating plug.
In Xylocaris maculipennis, the male will at times impale and inseminate other males while they are engaged in the process of copulation. This allows the rapist's genes to enter the bloodstream to be carried to females by the victim. In this way, the rapist conceives by proxy. In A Natural History of Sex, Adrian Forsyth writes, "The sperm of the rapist enters the vas deferens of his male victim and is used by the victim during copulation." This also occurs with fresh water snails of the genus biomphalaria, which are vectors for schistosomiasis (Forsyth 1991).
Method of initial infestation
With the widespread use of DDT in the 1940s and '50s, bedbugs all but disappeared from North America in the mid-twentieth century. Infestations remained common in many other parts of the world, however, and in recent years have begun to rebound in North America. The insects have become epidemic in the Boston neighborhoods of Allston and Brighton, Massachussetts, where in 2004 renters were offered subsidies to replace infested mattresses.
Another reason for their increase is that pest control services more often nowadays use low toxicity gel-based pesticides for control of cockroaches, the most common pest in structures, instead of residual sprays. While residual sprays meant to kill other insects resulted in a collateral insecticidal effect on potential bedbugs infestations, gel-based insecticides do not have any any effect on bedbugs as they are incapable of feeding on these baits.
There are several means by which dwellings can become infested with bedbugs. People can often acquire bedbugs at hotels, motels, and bed-and-breakfasts, thanks to increased domestic and international tourism, and bring them back to their primary domiciles in their luggage. They also can pick them up by inadvertently bringing infested furniture or used clothing to their household either via purchase or "dumpster diving". If someone is in a place that is severely infested, bedbugs may actually crawl onto and be carried by people's clothing, although this is atypical behavior — except in the case of severe infestations, bedbugs are not usually carried from place to place by people on clothing they are currently wearing. Finally, bedbugs may travel between dwellings (such as condominiums and apartment buildings, after being originally brought into the building by one of the above routes. This spread between units is dependent in part on the degree of infestation (if the infestation has not been reported), on the structure of the building (less likely if hte partition walls are concrete), and if infested items are dragged into the hallway and bedbugs fall off and then find their way into other units.
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