Adult bed bugs are light brown to reddish-brown, flattened, oval-shaped and have no hind wings, but front wings are vestigial and reduced to pad-like structures. They have segmented abdomens with microscopic hairs that give them a banded appearance. Adults grow to 4–5 mm in length and 1.5–3 mm wide. Newly hatched nymphs are translucent, lighter in colour and become browner as they moult and reach maturity. Bed bugs may be mistaken for other insects, such as booklice, small cockroaches, or carpet beetles, however when warm and active, their movements are more ant-like, and like most other true bugs, they emit a characteristic disagreeable odor when crushed.
The life span of bed bugs varies by species and is also dependent on feeding.
Bed bugs can survive a wide range of temperatures and atmospheric compositions. Below 16.1 °C (61.0 °F), adults enter semihibernation and can survive longer; they can survive for at least five days at −10 °C (14 °F), but will die after 15 minutes of exposure to −32 °C (−26 °F). They show high desiccation tolerance, surviving low humidity and a 35–40 °C range even with loss of one-third of body weight; earlier life stages are more susceptible to drying out than later ones. The thermal death point for C. lectularius is high: 45 °C (113 °F), and all stages of life are killed by 7 min of exposure to 46 °C (115 °F). Bed bugs apparently cannot survive high concentrations of carbon dioxide for very long; exposure to nearly pure nitrogen atmospheres, however, appears to have relatively little effect even after 72 hours.
Bed bugs are obligatory hematophagous (bloodsucking) insects. Most species feed on humans only when other prey are unavailable. Bed bugs are attracted to their hosts primarily by carbon dioxide, secondarily by warmth, and also by certain chemicals.
A bed bug pierces the skin of its host with what is called a stylet fascicle. This is a unit composed of the maxillae and mandibles which have been modified into elongated shapes from a basic, ancestral style. The right and left maxillary stylets are connected at their midline and a section at the centerline forms a large food canal and a smaller salivary canal. The entire maxillary and mandibular bundle penetrates the skin. The tips of the right and left maxillary stylets are not the same; the right is hook-like and curved, and the left is straight. The right and left mandibular stylets extend along the outer sides of their respective maxillary stylets and do not reach anywhere near the tip of the fused maxillary stylets. The stylets are retained in a groove in the labium, and during feeding, they are freed from the groove as the jointed labium is bent or folded out of the way; its tip never enters the wound. The mandibular stylet tips have small teeth and through alternately moving these stylets back and forth, the insect cuts a path through tissue for the maxillary bundle to reach an appropriately sized blood vessel. Feeding by sucking for about three to five minutes or more, the bug then withdraws the stylet bundle from the feeding position and retracts it back into the labial groove, folds the entire unit back under the head, and returns to its hiding place It takes between five to ten minutes for a bed bug to become completely engorged with blood."
Although bed bugs can live for a year without feeding, they normally try to feed every five to ten days. In cold weather, bed bugs can live for about a year; at temperatures more conducive to activity and feeding, about five months.
At the 57th Annual Meeting of the Entomological Society of America in 2009, newer generations of pesticide-resistant bed bugs in Virginia were reported to survive only two months without feeding.
DNA from human blood meals from bed bugs can be recovered for up to 90 days, which may allow them to be used for forensic purposes for identifying on whom the bed bugs have been feeding.
All bed bugs mate by traumatic insemination. Female bed bugs possess a reproductive tract that functions during oviposition, but the male does not use this tract for sperm insemination.Instead, the male pierces the female's abdomen with his hypodermic genitalia and ejaculates into the body cavity. In all bed bug species except Primicimex cavernis, sperm are injected into the mesospermalege, a component of the spermalege, a secondary genital structure that reduces the wounding and immunological costs of traumatic insemination. Injected sperm travel via the haemolymph (blood) to sperm storage structures called seminal conceptacles, with fertilisation eventually taking place at the ovaries.
Male bed bugs sometimes attempt to mate with other males and pierce the latter in the abdomen. This behaviour occurs because sexual attraction in bed bugs is based primarily on size, and males will mount any freshly fed partner regardless of sex.The "bed bug alarm pheromone" consists of (E)-2-octenal and (E)-2-hexenal. It is released when a bed bug is disturbed, as during an attack by a predator. A 2009 study demonstrated the alarm pheromone is also released by male bed bugs to repel other males who attempt to mate with them.
C. lectularius and C. hemipterus will mate with each other given the opportunity, but the eggs then produced are usually sterile. In a 1988 study, one of 479 eggs was fertile and resulted in a hybrid, C. hemipterus × lectularius.
Bed bugs have six life stages (five immature and an adult stage). They will shed their skins through a molting process (ecdysis) throughout multiple stages of their lives. The discarded outer shells look like clear, empty exoskeletons of the bugs themselves. Bed bugs must molt six times before becoming fertile adults.
Bed bugs can cause a number of health effects, including skin rashes, psychological effects and allergic symptoms. They are able to be infected by at least 28 human pathogens, but no study has clearly found the insect is able to transmit the pathogen to a human being. Bed bug bites or cimicosis may lead to a range of skin manifestations from no visible effects to prominent blisters. Diagnosis involves both finding bed bugs and the occurrence of compatible symptoms. Treatment involves the elimination of the insect but is otherwise symptomatic. They have been found with methicillin-resistant Staphylococcus aureus MRSA and with vancomycin-resistant Enterococcus faecium (VRE), but the significance of this is still unknown.
Dwellings can become infested with bed bugs in a variety of ways, such as:
- Bugs and eggs inadvertently brought in from other infested dwellings by visiting pets, or a visiting person's clothing or luggage
- Infested items (such as furniture, clothing or backpacks) brought in
- Nearby dwellings or infested items, if easy routes are available for travel (through duct work or false ceilings)
- Wild animals (such as bats or birds) that may also harbor bed bugs or related species such as the bat bug
- People or pets visiting an infested areas (apartment, subway, movie theater, or hotel) and carrying the bugs to another area on their clothing, luggage, or bodies
Bed bugs are elusive and usually nocturnal, which can make them hard to spot. They often lodge unnoticed in dark crevices, and eggs can be nestled in fabric seams. Aside from bite symptoms, signs include fecal spots, blood smears on sheets, and molts.
Bed bugs can be found singly, but often congregate once established. They usually remain close to hosts, commonly in or near beds or couches. Harborage areas can vary greatly, however, including luggage, vehicles, furniture and bedside clutter. Bed bugs may also nest near animals that have nested within a dwelling, such as bats, birds, or rodents. The eggs of bed bugs are found in similar places where the bed bugs themselves are found, and are attached to surfaces by a sticky substance. Attractant devices for detection use heat and/or carbon dioxide.
Bed bugs can be detected by their characteristic smell of rotting raspberries. Bed bug detection dogs are trained to pinpoint infestations, with a possible accuracy rate of 97.5%, based upon tests conducted under controlled conditions by researchers.The success rates in these tests may not reflect real-world success rates of pest companies’ dogs, operating with many more variables in the field. Dog detection can often occur in minutes where a pest control practitioner might need an hour. In the United States, about 100 dogs are used to find bed bugs as of mid-2009.A few companies are experimenting with high speed gas chromatography to detect bed bugs and other insect vermin.
Eradication of bed bugs frequently requires a combination of pesticide and nonpesticide approaches. Pesticides that have historically been found to be effective include: pyrethroids, dichlorvos and malathion. Resistance to pesticides has increased significantly over time and negative health effects from their use are of concern. Mechanical approaches, such as vacuuming up the insects and heat treating or wrapping mattresses, have been recommended.
The carbamate insecticide propoxur is highly toxic to bed bugs, but in the United States the Environmental Protection Agency (EPA) has been reluctant to approve such an indoor use because of its potential toxicity to children after chronic exposure.
Natural enemies of bed bugs include the masked hunter (also known as "masked bed bug hunter"), cockroaches, ants, spiders (particularly Thanatus flavidus), mites and centipedes. The Pharaoh ant's (Monomorium pharaonis) venom is lethal to bed bugs. Biological pest control is not very practical for eliminating bed bugs from human dwellings.
The New York City Department of Health and Mental Hygiene has published a bed bug guide (PDF) that is also available for download in Spanish (PDF) and Chinese (PDF).
Call 311 to request a free copy of the English-language printed booklet. You can use this basic and easy-to-follow guide to spread awareness about bed bugs and to educate neighbors, landlords and friends who are new to the problem. (Check our resources page for more bed bug management guides.)