Cimex lectularius - common bed bug
Cimex hemipterus - tropical bed bug
Newly hatched bed bugs are minute in size, increasing to a few millimetres after their first moult. The adult bed bugs are much larger, approximately 5-8mm long.
When they first hatch the young hatchlings are pale yellow to cream becoming chestnut brown to dark brown once they have begun feeding.
Bed bugs have a short, broad head with a pair of prominent antennae and a pair of small dark compound eyes. They have three pairs of well-developed legs with clawed feet which allow them to climb rough surfaces and to crawl rapidly.
They are oval to round in shape with unfed specimens being paper thin until they have fed.
They feed by rotating their long slender piercing mouthparts down from beneath the head and thorax.
Bed bugs are closely associated with humans and the domestic environment throughout their lifecycle. They cannot fly so they either crawl or are passively transported in luggage, furniture, books or clothing.
They can withstand several months without feeding which increases their chances of survival leading to wide distribution throughout the world.
These insects are generally associated with poor and unhygienic conditions, as well as areas of high transient populations such as hotels and hostels.
They are usually found in bedrooms where they hide away in cracks and crevices e.g. the bedframe, furniture, skirting boards, wallpaper, close to where the hosts sleep. They emerge at night, usually just before dawn, to feed on the blood of sleeping hosts. Their presence can be seen by the dark spotting of surfaces around harbourages caused by their faeces.
Bed bugs feed on human blood but will also feed on the blood of rodents, rabbits, bats and birds if necessary.
Bed bugs develop though incomplete metamorphosis . The nymphs are miniature replicates of the adults but without wing buds or sexual organs.
The female bed bug lays her eggs in harbourages around the bed frame, skirting board, cupboards, and chests of drawers. She will lay 2 - 3 eggs per day throughout her adult life. The eggs are approximately 1 mm long, yellowy white and vase shaped. The eggs are coated with a thin quick drying glue which cements them to the surface. The hatched eggs are translucent.
The eggs hatch within 10 - 20 days at room temperature (20 C), but will hatch much quicker at higher temperatures.
There are 5 immature (nymphal) stages before the adult emerges. Each nymph requires one full blood meal before moulting to the next stage.
The total development time of the bed bug can take from 9 - 18 weeks with the adult bed bugs living for between 9 - 18 months.
The increased use of central heating and sealed windows provides higher temperatures and humidities, allowing continued feeding and a subsequent increase in the number throughout the winter.
The lowest temperature in which a bed bug will complete its life cycle is 13 C.
Bed bugs have not been proven to be a disease carrier although there are current studies underway to ascertain this.
A diagnosis of a bed bug infestation can be made through finding a specimen, alive or dead, and the presence of black faecal marks which are left around their harbourages. These marks look like an ink spot and may also be on the bed sheets where they may have come out for a feed.
Bed bug bites are commonly found on the face, neck, arms, or hands, sometimes on other exposed areas of the body. As bed bugs are attracted to carbon dioxide these bite sites tend to be towards the top of the body when the host is lying down asleep.
The bite usually presents itself as a raised wheal - a large oblong inflamed spot - which usually occurs as the result of an allergic reaction. This reaction is thought to be due to the saliva of the bed bug which it injects into the host to prevent the blood from clotting as it takes a feed. This is often followed by severe itching and inflammation of the area a few hours later.
Some people do not always react to the bite of a bed bug; this is usually because they have been bitten before and are de-sensitised to the bite. Other people can have an extreme reaction to a bite including severe hypersensitivity and asthmatic symptoms.
Bed bug infestations can be treated with thorough spraying with a residual insecticide by a reputable pest control company, or the local council.
Bedding should be regularly washed and dried at high temperatures incase any bed bugs remain on the bedding. Although this is a precautionary measure as bed bugs prefer to live in screw holes, bed frames mattresses and skirting boards around the area of the sleeping host.