Monthly Archives: November 2013

IDENTIFICATION AND BIOLOGY

Bedbugs are pests of humans, domestic animals, bats, rodents, rabbitsand wild birds. Worldwide,two species commonly attack humans. One of these, Cimex lectularius, is widely distributed over most of the world, and it is the species that is most common in temperate North America.

During the first half of the 20th century, the bed bug was a common household pest and was a scourge for travelers, for it was common even in respectable hotels. The importance of this insect gradually diminished with improvements in household cleanliness, personal hygiene and the increased availability and use of effective residual insecticides. In developed nations, they declined in incidence, and infestations became a rare event. In the last few years, this downward trend has started to reverse, and globally there have been reports of an increase in bed bug numbers.

Bed bugs are wingless insects, roughly oval in shape, 5-6 mm long when fully grown and fast crawlers. The juvenile stagesare pale cream colored, and the adults are rust brown,becoming adeeper red-brown following a blood meal. Bed bugs are dorsoventrally (top to bottom)flattened and can hide in cracks and crevices, making detection very difficult.

There are five juvenile stages known as nymphs, each lasting 2.5 to 10 days. The nymphs are miniature versions of the adults in general appearance. Each nymphal stage requires at least one blood meal to molt to the next stage, and it takes 3-5 minutes to complete a blood meal. The length of the lifecycle is extremely variable and is dependent on temperature. The temperature threshold for development is about 60 degrees, with optimal development at 86 degrees. The total development time from egg to adult for C. lectularius varies from 24 days at 86degrees to 128 days at 65 degrees. In average conditions, around 74 degrees, the lifecycle takes around two months to complete.

All nymphal stages and adults of both sexes require blood for nutrition and development. At low temperatures, nymphs may survive for five to six months without feeding, whereas adults can survive even longer. For example, in cold conditions, they can live almost two years, even without a blood meal. Mated females usually feed to engorgement and then begin to lay eggs three to six days later. Typically, each female lays two to three eggs a day. The cream-colored eggs are cemented on rough surfaces of hiding places, and nymphs will hatch within approximately nine days at a room temperature of 74 degrees. Also, depending on environmental conditions, female bed bugs may feed every three to four days.

The mouthparts of bedbugs are especially adapted for piercing skin and sucking blood. Bed bugs respond to the body warmth of a host and quickly locate a suitable feeding site. They tend not to live on humans, and the only contact is for a blood meal. Blood feeding typically occurs at night.They tend to seek shelter during the day and are inactive while digesting the blood meal. However, bed bugs are opportunistic and will bite in the day, especially if starved for some time.

Bed bugs seek shelter in a variety of dark locations, mostly close to where people sleep. These include under mattresses, floorboards, paintings andcarpets; in various cracks and crevices of walls; within bed frames and other furniture; and behind loose wallpaper. Bed bugs typically stay in close contact with each other, and heavy infestations are accompanied by a distinctive sweet, sickly smell. Blood spotting on mattresses, bed linen, nearby furnishings and walls is often a telltale sign of an infestation.

Bed bugs are public health pests largely because of their nuisance biting, and often the most serious health aspect for many individuals is the mental trauma of knowing there is an infestation. Skin reactions, which are commonly associated with bed bugs, result from the saliva injected during feeding. Some people do not react to their bite, whereas others can experience a great deal of discomfort and loss of sleep from the persistent biting. The most commonly affected areas of the body are the arms and shoulders. Reactions to the bites may be delayed, with up to nine days before lesions appear. Common allergic reactions include the development of large wheals, which are accompanied by itching and inflammation. The wheals usually subside to red spots and can last for several days.

Although it hasbeen suggested that bed bugs may transmit of a wide variety of infectious agents, there has never been a proven case of a disease agent being passed on to humans by bed bugs.

Original post:
Bed Bugs - LSU AgCenter