Left a heteropteran land bug. Their bodies are generally flattened, with the wings folded flat over the body. The mouthparts (stylets or rostrum) form two channels allowing food to be sucked up one and saliva to be pumped down the other. This bug belongs to the Pyrrhocoridae family, many of which are seed eaters. This is Pyrrhocoris apterus (the fire bug), and is the only member of the family found in Britain, though it is not common. In Europe it can sometimes be seen in huge numbers in spring crawling through the vegetation.

Bed bugs (below right and left) are in the Cimcidae family. There are 90 species found worldwide on birds and mammals. They are usually 4 - 12 mm long, have small compound eyes, and all suck blood through their rostrum which is kept folded underneath the body when not feeding. The bed bug which parasitises humans is is Cimex lectularius. The drawing below left shows typical hemimetabolous metamorphosis, i.e. after hatching from the egg the change to adult form is gradual, and

there is no resting stage in a chrysalis. They are flat and reddish brown. Their compound eyes have around 30 facets. Males have a more pointed end to the abdomen than females.

Behaviour. They can crawl over many vertical surface including wood, plaster, paper and dirty glass - they cannot crawl up smoother surfaces. The insect increases its weight from 2 - 6 times after a full meal, and it takes just 5 - 10 minutes to fill itself with blood. They can withstand long periods of starvation - at least 2 months in normal indoor temperatures - and there have been reports of individuals surviving a whole year without feeding. They can also withstand temperatures below freezing. As can be expected they are usually found in bedrooms. They usually wait until night time to emerge.

Lifecycle. The egg is laid in cracks and crevices and cemented into place with glue. A well-fed, healthy female can lay up to 500 eggs in her life, usually at a rate of 3 - 4 per day which she lays in crack and crevices. The eggs measure around 1.0 x 0.5 mm. There are 5 nymphal stages, and the transition from one stage to the next can only occur after a blood meal, and the nymphs are capable of sucking blood as soon as they hatch out of the egg. In good conditions an adult can live for as long as 18 months, but 2 - 10 is more usual.

Mating. Their mating habits are rather unusual. There is no courtship, and the males practice "traumatic insemination". This means that the male simply injects his sperm into the female's body with his sharp sexual appendage. A female lays around 150 eggs in her lifetime, usually at a rate of 2 or 3 a day. They are active at night, and during the day they hide in crevices, behind pictures and wallpaper or in bedding. They locate their host by smell and body heat. In the UK they are not thought to transmit disease.

Infestation is most common through buying infested bedroom furniture. They can also be transported from infested rooms in suitcases, and even in clothing that has been hanging next to a wall. They travel to adjacent rooms and houses through cracks in brickwork and joinery. Treatment. Destroy both mattress and bed. Put them out of the window, if you can rather than risk carrying them through the house and spreading eggs. Either destroy all the other contents of the room or, put the contents in plastic bags whilst in the room, then put these bag into a freezer that can reach temperatures of -20^oC or lower, and leave the bags there for at least 24 hours. Then get professional pest controllers to treat the room.

Itching. Some people develop severe itching after being bitten, and this can be relieved by applying hydrocortisone cream.

Evolution. It is thought that the bed bug may have evolved from a blood-sucking bug found on bats when early humans shared the same caves as bats.