Order: Hemiptera (‘half-winged’ true bugs)
Two pairs of wings normally present; mouth parts piercing and sucking, forming a beak, or rostrum, normally held under the body. Metamorphosis usually incomplete, with egg and nymphal stages.
Flat, oval insects, with very short, functionless forewings; hindwings absent; rostrum lies in a ventral groove; tarsi 3-segmented; exclusively bloodsucking.
Common bed bug (Cimex lectularius)
Adults, 5mm long; reddish-brown in colour, becoming purple after feeding; well-developed antennae; prominent, simple eyes; feet clawed so can climb rough but not smooth surfaces; ratio of head width (including eyes) to length of third antennal segment usually greater than 1.7.
The principal host is man, though other warmblooded animals can be parasitised. Found in human habitations throughout the world.
AREAS WHERE FOUND:
As bed bugs cannot fly, they must either crawl or be passively transported in clothing, or more probably in luggage, furniture, books and other objects used as harbourages. Their ability to withstand many months without feeding increases their chances of surviving such transportation and the insects’ very wide distribution throughout the world demonstrates their success. Household’s, hotel’s etc. can be invaded by bed bugs, but it is likely that infestations will only become established in premises with low standards of hygiene. Bed bugs are often associated with poor, crowded and unhygienic conditions. Most bed bug infestations are to be found in domestic premises, usually in the bedrooms. Both juveniles and adults live similar lives, hiding away in cracks and crevices for most of the time and coming out at night, usually just before dawn, to feed on the blood of their sleeping hosts. Their hiding-places will be close to where their hosts sleep: in the bed frame or the mattress, in furniture, behind the skirting, behind the wallpaper - anywhere that affords a dark harbourage during the daylight the daylight hours for these nocturnal creatures. The insect infestations occur particularly in areas of high population density including hotels, hostels and holiday camps. In temperate climates bed bugs reach their peak numbers towards early autumn. At this time all stages in the lifecycle will be present. With the onset of colder weather their activity decreases, egg-laying ceases and development of the juvenile forms slows down. Bed bugs overwinter mainly as adults, since the eggs and nymphs are more susceptible to low temperatures and die out with the onset of winter, unless in adequately heated premises. The bird-feeding bugs, such as the Martin bug, will be found in the nests of their hosts and follow a similar lifestyle to the Common bed bug. The occasional problems of these species attacking humans are likely to stem from abandoned nests built near to or inside houses. Nests in lofts or under eaves would be a likely source if such an infestation were suspected.
IMPORTANCE AS A PEST:
It is not known that bedbugs transmit any diseases to humans but skin reactions are associated with bed bug bites and can occur on any part of the body. It is the saliva injected into the bites that cause these reactions. The reaction to these bites will vary and the effects are not permanent. Large infestations of bed bugs have been known to cause anaemia.
Both sexes take a blood meal, therefore distinguishing between sexes is not important. Feeding is done on a sleeping person usually late at night or early morning. Very hungry bedbugs have been known to feed during the daytime. Bed bugs differ from lice and fleas in that they do not stay on the host for a long period. They generally leave after a blood meal. During the day both adults and immatures hide in cracks in walls, furniture, floors, underneath mattresses and bedding. Bed bugs are gregarious feeders and are often found in groups and under heavy infestation one can even smell them. Although bed bugs cannot fly, they can move very rapidly if disturbed. Bed bugs are one of the world's biggest travellers, they are distributed in luggage, furniture, clothing, bedding, and on traveller's bodies. For this reason they enjoy a worldwide distribution. Their presence is normally indicated by nymph husk, empty egg casings or chorions, as well as black spots due to diuresis or excrement containing excess blood.
Females produce 2-3 eggs per day often large groups of eggs are present. Eggs are approximately 1 mm in length white to yellowish-white with a mosaic pattern. The female can live up to a year and during this time she can lay hundreds of eggs. Eggs hatch within 6-11 days and do not hatch in temperatures below 14°C. Bedbugs are hemimetabolous therefore the nymphs look like the adults. There are five nymphal instars, which have to take a blood meal between each moult. The immatures cycle last for 5-8 weeks and in the absence of a human host will also feed on other mammals like rabbits, mice or poultry. Bed bugs can stay without food for long periods of up to 500+ days under favourable environmental conditions.
In all infestations, particularly those newly established in well-kept houses, an attempt should be made to determine the source of infestation, so that proper measures can be taken. A thorough inspection of infested premises should also seek to uncover the extent of the infestation, since the measures necessary for control will depend on whether the infestation is established and widely distributed throughout the premises, or recently introduced and likely to be more localised. Control measures used must be thorough and be directed at all the harbourages. In circumstances where the infestation has originated from birds’ nests, it will be necessary to treat the nests and advisable to birdproof the building.
High standards of hygiene and house-keeping are unlikely to provide an adequate method of control, but will reveal the presence of bed bugs at an early stage, making control easier. Bed bugs can only proliferate if they are tolerated. If they are suspected, a close inspection of the bed, the mattress around the seams, the back of the headboard, etc., should reveal their presence. The use of a pyrethroid-based aerosol sprayed lightly around these areas may help, as the insects will be driven out of their hiding places. The finding of eggs or egg cases and the blackish spots of bug excrement will also indicate their presence. Infested bedding (e.g. sheets) and clothing should be laundered or burnt and the fabric of infested rooms thoroughly cleaned. Particular attention should be paid to removing dust, fluff and debris from insect harbourages eg cracks, crevices, seams of fabrics, buttons on mattresses etc.
- Insecticidal control:
To eradicate the infestation it will be necessary to treat the premises thoroughly with suitable insecticides (see recommended products), including the beds, other furniture and harbourages in the fabric of infested rooms. A professional pest control organisation should be used, as the detection and thorough treatment of all bed bug hiding places is a job which requires experience.