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Insect Pests

Bed Bugs (Cimex lectularis)

Characteristics: Reddish brown, size .65cm in length
Behaviour: bedbugs are the most commonly known ectoparasites to humans. These parasites are blood feeders, and they drawl into beds during the night while their victims sleep. The bite is painful for people with sensitive skin, and a number of bedbugs may feed for a longer period of time on any area of exposed skin. The resulting bite wound may show minor swelling into a raised bump followed by itching.

Bed bugs feed on humans, usually at night when they are asleep. They feed by piercing the skin with their elongated mouthparts, which consist of two stylets that normally fold under their body when at rest but fully extend during blood-meal feeding. One stylet has a groove that carries saliva into the wound, while the other has a groove through which body fluids from the host are taken in.

A single feeding may take up to 10 minutes, and feels like a pin prick, but because feeding usually occurs at night when people are asleep they are not aware they have been bitten until afterwards. However, saliva injected during the feeding can later produce large swellings on the skin that itch and may become irritated and infected when scratched. Swelling may not develop until a day or more after feeding, and some people do not show symptoms. Bed bugs currently are not considered to be disease carriers.

Distinguishing bed bug bites from the bites of other arthropods such as mosquitoes, fleas, and spiders is difficult. People often confuse itching bed bug welts for mosquito bites. The only way you really can confirm bed bugs are the cause is to find the bugs in your bed or bedroom. Often people are bitten when traveling, making diagnosis even more difficult.

In addition to the direct injury to humans, bed bugs have stink glands that leave odors. They also leave unsightly fecal spots on bed sheets and around their hiding places. These spots are darkish red in color, roughly round, and can be very small.
Monitoring and Detection

You can detect a bed bug infestation by searching for the pests or their fecal spots, egg cases, and shed skins (exuviae). Current research reports more than 85% of bed bugs are found in or near the bed, so inspections for infestations should focus on the mattress, bed frame, and headboard areas. Lift the mattress and inspect all seams and surfaces as well as the box springs. You may need to dismantle the bed. Use a flashlight to aid the inspection process.

Remember, these nocturnal insects are small. Although you can see adults and aggregations of nymphs with the unaided eye, seeing the eggs requires a hand-magnifying lens. It may be easier to detect dark spots of dried bed bug excrement or the insects’ light-colored shed skins. A foul, rotting, bloody-meat smell might be present in heavily infested areas.

In addition to the bed area, the remaining 15% of infestations usually are in upholstered furniture other than beds, in bedroom cabinets, along baseboards, under wallpaper, and in carpets, wall hangings and similar hiding spots. Bed bugs prefer fabric or wood surfaces to metal or plastic. For heavy infestations, adjoining rooms, filing areas, and clutter can be out-of-way shelters. It takes patience and perseverance to find low-level infestations of such a persistent, nagging problem.

Recent research has shown searching with dogs can be an effective method for finding bed bug infestations. Under laboratory and simulated-field conditions, using dogs to search for bed bugs was 97% effective. Other recent research indicates using small, double-cupped monitors that are easily installed on the leg ends of beds trapped six times more bed bugs than were found from human visual searches alone. This trap, Interceptor, is commercially available.

A new university study indicates an airborne aggregation pheromone, a behavior-modifying chemical, might help control infestation levels. With this new research, hopefully traps attractive to bed bugs soon will be commercially available.

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