Wasp or hornet

Usually there is no doubt. When we talk about the wasp and its nest, we talk about the familiar black and yellow insect with that recognisable waist. The only problem is that there are other kinds of wasps like wood wasps, sawflies and many more. If you want to be accurate, you use the name hornet on the social species that belong to the family Vespidae.

We have seven species of social, community-forming, hornets in Northern Europe. They are very similar and live the same kind of life. Only the big hornet Vespa crabro, that is twice as large as its relatives, stand out.
A year in a wasp society In autumn a number of new queens and males are born in the nest. They swarm out and mate. Males die soon, but the fertilised young female wasps start looking for a reasonably sheltered place for them to spend winter. It may be in a hollow tree or a moss pillow, but often they find a good place in or on a house, in a crawl space or in an attic. If the nest warms up during winter, they wake up, and this explains the sudden appearance of dull wasps when an otherwise cool room is heated up in the middle of winter.

But when everything is right, they are awakened by the spring sun and flies out in mid-April. The new queen now gets busy. She must eat sugar and she must find a suitable place to found a new society. And our houses offer great places for wasps’ nests. Other wasps prefer holes in the ground, maybe an abandoned mouse’s nest, or a hollow tree, as the wood wasps prefer. She then start building the first nest, spherical, about the size of a ping pong ball. It contains 10-20 hexagonal cells and she lays an egg in each. When the eggs hatch, she must fetch food for the larvae, and only after the first litter of workers hatches about a month later, the queen can relax and concentrate on laying eggs. The workers are now taking over the work of expanding the nest and fetch feed for the new larvae. It is a vulnerable period and if the weather is cold, many queens die before they are finished with the work, and that means a year with only few wasps.

The nest is simply made of paper. The material is produces by the hornets by rasping fine fibres of plant stems and wood. They chew it with saliva until it gets the right texture and can be built into the nest, where it is needed. Actually it was hornets that inspired the first attempts to manufacture the paper we know today, and which replaced the paper that was made from old rags.

The feed for the larvae is meat. Wasps are hunters who catch flies, butterflies, honey bees and other insects in the air. They kill large prey with their sting. The part the prey, and chew it to round feed buns. They can also cut chunks of carrion or retrieve small pieces of roast from lunch tables. When they feed the larvae with these meat buns the larvae regurgitate a drop of a sugary substance. The adult wasps eat this. It gives them energy and perhaps even motivation to care for the larvae.

That is the summer in the wasps’ lives. Their community continues to grow and it can grow to be the size of a football and contain 5-6000 individuals in September. It is then the new queens and males are born and leave the nest, and little by little the community collapses; the workers stop working, and they no longer feed the larvae.

In November the nest is completely dead and hangs back as nothing but a hollow shell. The problem for wasps (hornets) in these latitudes is that they do not, like the honey bees, store food for the cold months, and then must start fresh every spring.

Wasps rarely occur as pests and in most cases you can live harmoniously as neighbour to a wasp’s nest. But if you are allergic to their stings or they appear in large numbers in a nursery, or if there simply are so many that it becomes really annoying, it is of course reasonable enough to find the nest and defuse it.
A wasp’s nest can be defused in many ways. If you can get to the hole at the bottom of the nest, it is a safe method to spray the hole and fill the nest with a liquid containing pyrethroid of a kind. If the nest is in a wall cavity or perhaps in a hole in the ground, it is possible to dust the place where the wasps come in and out with an insect powder of some kind, so that the wasps get infected with the powder when passing this point. If the nest is somewhere free of the house, where it is safe to use open fire, it is of course a possibility to burn it , perhaps using a rag with kerosene on a stick.

If you are frequently annoyed by wasps in your house, it may help to mount dense insect screens over the places, where the queens often find their ways in, and it may be a good idea to install insect screens in the vents to the crawl space in the spring.




A single rat can be an intelligent and charming pet. Rats are useful animals, and certain places in the world, the rats that eat the villagers waste are used as a protein supplement to the diet.

But mostly we regard the rat as the ultimate pest, with their appetite for our food, their ability to spread diseases and their impressive adaptability and high reproductive potential.

Two rat species can be found in Northern Europe. The black rat, or the plague rat (Rattus rattus) came to Europe in the early Middle Ages, where it lived in best well-being, spreading diseases. It was the black rat fleas that transmitted the plague to humans, and was the cause of the epidemic “Black Death” that wiped out large parts of Europe’s population in the 1600s.

Today the black rat is a rare guest, it is sometimes introduced with shiploads and can be found in warehouses in ports. It does not thrive in European nature.

The black rat was in 1700 supplanted by the brown rat (Rattus norvegicus). This rat originated from East Asia but quickly spread with ships and on foot (hiking rat). Why Linné named it after his dear neighbours and called it the Norwegian rat is not known. The brown rat is larger, more aggressive and adaptable than its black relative.

Selma Lagerlöf describes in “Niels Holgersson’s Adventurous Journey” the war between the two rat species. In this tale we feel sympathi for the black rats and when the brown rats threaten to take their last refuge in Scania, Sweden, Niels Holgersson helps the black rats by luring the attacking brown rats away with a small flute. But the brown rats create problems in our part of the world today.

An adult rat is about 45 cm long and weighs about 300 g. It is normally dark brown with a lighter underside. Indoors, it breeds throughout the year. It can breed up to 5 litters, and as there can be from 4 to 12 pups in each litter, and considering that the pups reach maturity in just 3 months, it is obvious that it can quickly turn into a huge rat population.

Rats are practically omnivorous, they prefer cereal but they will just as well eat meat and can act as predators and even take chickens from chicken coops.

The rats are particularly often found in stables, warehouses and homes. In cities there will be a constant population of brown rats in the sewer systems and invasions are often caused by “sewer rats” that come up through a breach.

The brown rat is doing well in nature, in hedgerows, by streams and especially in places where waste is thrown out.
The rats are shy animals, and are primarily active when it is dark. They dare not go out in the open, but move along walls. They are, in contrast to mice distrustful of new things and do not immediately go into trap. They are also cautious about new foods, they taste carefully, and if it makes them sick they will never touch it again. This caution makes it difficult to accept the poison we serve them. The rats are able to relatively quickly develop resistance to the toxins we use.

The rats eat the equivalent of 1/10 of their body weight per day, they pollute foods, and they can even destroy buildings and installations with their gnawing. They have strong teeth and can gnaw everything softer than iron.
And not least they are dangerous disease carriers. Through their urine and droppings, they can spread the deadly, but quite rare Weil’s disease, and there is little doubt that they are responsible for a large part of the food poisoning caused by salmonella bacteria.

Therefore, it is obvious that rat control is very important. Nothing is left to the individual citizens. In most countries, the authorities are obliged to exterminate rats. .

Extermination of rats with chemical agents may only be performed by authorized persons.

The rats are difficult to to keep down in numbers, but the problems today are nothing compared to the past. Jeppe Aakjær is just one of many people describing how the rats ravaged his childhood home in the 1880s. The children lay and heard the rats make noises, often with a stick next to them to chase them away when they came trotting across the quilt. The children were even often bit in their noses.


Most of us can agree that a flock of pigeons flying around the church tower is a beautiful sight, and there is something nice about feeding the pigeons in the square. On the other hand, it is clear that they can be a serious nuisance when present in large numbers in places where we do not want them, and then we start calling them rats of the air.

Domestic pigeons originates from the rock pigeon (Columba livia). In the past, people bred countless varieties of domestic pigeons with all sorts of colours, shapes and properties. The pigeons we see in our cities look much like the rock pigeon.

Rock pigeons live along Western Europe’s coastal cliffs and deep in Asia’s mountainous regions. It has never lived wild in Scandinavia, and its descendants, our city pigeons, must cope with the artificial rock landscape that is our buildings.

Plague pidgeons

Pidgeons can be a pest in major cities.

They breed on the buildings where they can find suitable nesting places. The nest is very humble, often it is just a few sticks and perhaps a small piece of plastic in a cake of excrement.

The pigeons begin laying eggs in early spring, they lay only a few eggs but can do so 4-5 times every season. Both parents participate in incubation and later on also in feeding of the chicks. Pigeons feed their chicks in a very particular way. Their basic food are seeds of various kinds, and this is not optimal feed for chicks. However, a protein-rich liquid “pigeon milk” can be made of the seeds, when the adult squeezes them with its claws and chewing them with its beak.

Pigeons can be very troublesome. They mess with their droppings, their nesting materials can clog piping, and nests can be a breeding ground for mites and insects that we do not want in our homes.

Pigeons can also act as disease carriers. It is not common in western countries, but “pigeon dung” must be treated with care, and pigeons are not tolerated in food companies.

The most reasonable way to keep the pigeons’ numbers to a reasonable level, is by limiting their ability to breed. Primarily we have to prevent them from entering attics and other places where they can build nests protected from wind and weather.

Also exterior nesting and seating should be limited. Holes in a wall can be fenced with wire mesh and cornices can be inclined (more than 45 degrees). The pigeons can be kept away with steel or nylon threads, or with other systems (fakirs, pasta, etc.) traded for the purpose and usually installed by professional firms.

Scarecrows, aluminium foil, rotary mills, etc. generally only works for a very short time. Scare sounds are also not a very good method, as the pigeons get used to them. As well as other birds, pigeons have a bad sense of smell, so fragrances will not do either.

It is important to limit their ability to find food.

Traps are an option, the traps must be tended morning and evening and any chick must be killed. Nests and eggs should in all cases be removed as they can be a breeding ground for unwanted mites and insects.

Museum beetles

Museum Beetle

Museum Beetle

If you find small, irregular holes in the best and most expensive woolen goods, it is likely the museum beetle larvae (the family Anthrenus) that has gnawed in them.

They do not – just like clothes moth – leave traces of fibre strands or visible faeces, so it may initially seem a bit puzzling.

The adult museum beetles look like small ladybugs, but they do not have their clear, shiny colours. They have beautiful, dull, yellow, brown and grey colours caused by small coloured scales, distributed in a pattern across the elytra. this is the same principle that gives butterflies their colours.

It is especially in early spring, you see the adult beetles. They come out and if they have overwintered in a house, they will seek towards light, they go out into the wild to find food, which consists of nectar and pollen. One can then find them in abundance on plants as spirea and wild carrots. They mate in flowers and then the females find a place to lay their eggs. It has to be a place where the larvae are able to find food. The larvae are specialists in regards to their own diet, they feed on the very last dry remains of dead animals where the other scavengers give up. That is cartilage, tendons, hair and feathers. It is useful work to get this dead animal material into the “circle of life” again, but it is this exact ability to digest wool and feathers that brings them into conflict with us.

Favourable conditions are found in old birds’ nests where there are feather debris, and maybe a dead baby bird. A dry carcass, perhaps a dead mouse, in an attic is also suitable and they also lay eggs directly on woolen textiles
The larvae grow up to 5 mm. They look like tiny armadillos with a coat of brown, spiky hair. The larvae are sometimes called wooly bears, because they may actually look like adorable little bears. In the rear end, the museum beetle larvae have some characteristic tufts of long hair, which ends in a small arrowhead-like spike, and is therefore called arrow-hair. If you tease a museum beetle larva it is possible to see how the arrow-hairs, and there is no doubt that they serve as a defensive weapon. If the larva is under attack, it faces the rear end against the attacker, raises the hairs and turn them from side to side. They break easily and when predators get these hairs in the mouth or on the body, it has to clean it off, and the museum beetle larvae might escape.

Museum beetle larvae are usually a year to develop, but when food is scarce, it can take much longer. They can live long without food, they put their metabolism down and consume the nutrients they have stored. A unique feature is that they can grow downwards.

Like other insects, the larvae change skin several times during their growth, and they are generally larger at each moult. If they do not eat, they can grow smaller, and it has been shown that they also grow physiologically younger. It is interesting, for they have apparently managed to turn the usually inevitable process is it to grow older.

Museum beetles are very common and active animals, and a total prevention is not possible. It it possible to have the beetles and not see any damage from them. But if they appear in large numbers, and if there are be holes in wool goods, one must of course take action.

At first you must find out where they come from. As mentioned, birds’ nests under the roof is an obvious hotbed, but felt pads, forgotten wool goods in inaccessible places are also options.

The extermination must aim to eliminate the infestation, vacuum the surroundings thoroughly and if necessary treat with an approved insecticide. Wool garments are washed in the washing machine or placed 2-3 days in a freezer. If clean wool goods are kept in sealed bags they are protected against new attacks.

Museum beetles are feared guests on many types of museums. They can destroy textiles and destroy an insect collection completely.

Indian meal moths

Indian meal moths

Indian meal moths

Indian meal moths are also called chocolate moths Among the moths that can go into our foods, the Indian meal moth (Plodia interpunctella) is most likely to occur in households, shops and food.

It is actually a pretty little butterfly, 1 cm. from antennae to the rear.

The wings are two-toned, the front third is light grey, the rest has a warm red-brown colour.
These moths fly mostly in the dusk, but are attracted by light. In the day, they sit on walls with the wings covering their rear.

The adult female moth lays eggs – up to 500 – in dry plant products. She can lay eggs in flour and cereals, but prefers dried fruit such as prunes, dates and raisins but also nuts, almonds and cocoa beans belong to her favourites.

When the eggs hatch, they small larvae start feeding. The look like typical caterpillars with a dark head, provided with powerful jaws and the body is provided with three pairs of legs and five pairs of prolegs. When conditions are favourable, they have food and a temperature around 25 degrees C. they become full-grown in a good month and then they are ready to pupate. Like other caterpillars – the silk moth is the most famous – they can produce silk, and silk threads in the infested items it is a sure sign that moth larvae are present.

When the time of pupation approaches, the larvae become restless and seek out of whatever has been their home and pantry. In contrast to the adult moth they gnaw and they can easily gnaw through cardboard and plastic packaging. Usually they seek upward, and in this stage, you can see the larvae crawl up the walls until they find a suitable slot where they can stay until they, usually after a few weeks, appear as adult moths. Here they also use their ability to spin. They produce a solid, white silk cocoon before they pupate, and in this they are protected while they are in the pupal stage.

It may be hard to avoid getting moths into a household or business. Individual eggs or larvae in a product are difficult to detect. If you suspect moths in goods, a cold treatment – a few days in a freezer – will be effective.
Extermination of the adult moths can be done with a spray approved for the purpose. Infested items should of course be discarded or cold treated. The problem is that the larvae and pupae can be hidden in crevices and cracks, which may appear as moths weeks later. In a household it is therefore necessary to shop small portions at a time and as far as possible keep fragile goods in a tight sealed packaging until you are sure that no more moths emerge from their hiding places.

Light traps or pheromones show if there are any moths flying around the room, and warn you that something must be done.

The concept of chocolate moths also includes the species cocoa moth (Ephestia elutella) and tropical warehouse moth (Ephestia cautella), they have a similar way of life as the Indian meal moth, but are grey in colour.




Cockroaches, that look exactly like the ones we see today, have existed for at least 250 million years. Their way of life has probably been more or less as the current cockroaches, except that it would take approximately 250 million years before the first cockroach got the chance to eat crumbs in kitchens.

Only a few members of this ancient insect family give cockroaches their bad reputation. The vast majority of the more than 4000 different known species live out in nature, and have as little to do with people as possible.
We also have a few species of outdoor cockroaches in Northern Europe. Small, neat insects that can be found in forests and dunes.

Cockroaches are predominantly tropical animals, and kitchen cockroaches also demand heat and are not found outdoors. It is only during the last few hundred years they have gained a place in these latitudes. Earlier on our homes were too poorly heated.

The German cockroach is not particular German, but Carl von Linné who named it Blatella germanica must have thought so.

The first sign that you have cockroaches in your house is quite large, slightly flattened animals with long legs and very long antennae that run into hiding when a light is turned on at night in the kitchen.

The adult German cockroach is about one cm long, brownish with two dark stripes on the breastplate. It has a pair of flying wings under the elytra but rarely makes any use of them.

After mating the female lays the eggs in a special capsule. It is divided into 30-40 small rooms containing an egg each. Many species leave the capsules, but the German cockroach carries it around, sticking out of the vulva, until the offspring is ready to swarm out. The offspring is wingless and relatively wide and dark compared to the adults. They evolve through 6-7 nymphal stages, and at 30 degrees C. they are fully grown in just two months. At a temperature of down to 21 degrees C. the development lasts half a year.

Cockroaches are gregarious insects, and they are often found in large numbers in those places where they hide during daylight. they have certain fragrances that form in their glands in the intestine and these fragrances are excreted with the faeces, which attracts them to each other and which they perceive by the sense organs in the antennae. It has been proven that a lone, young cockroach thrive poorly and grows more slowly than when it has company. Apparently the young cockroaches stimulate each other in some way.

The German cockroaches thrive in warm, moist places with access to water. This means that the usual living spaces are behind washing machines and ovens and in cracks behind the other heat sources.
The spread of cockroaches happens predominantly passive, along with products and packaging, but they can also easily spread in a property through piping or vent ducts.

Cockroaches can damage food by chewing, by polluting with their droppings and by that extremely unpleasant odour that cockroaches have.

Finally they can transfer germs to the goods, something that hardly has any significance in most countries today compared to other disease transfers.

You should always exterminate cockroaches, and in shared kitchens and food companies you are even obligated to do so.

Their high reproductive potential and hidden lifestyle makes them difficult to exterminate, and it does not get any easier knowing that the cockroaches are among the insects that quickly develop resistance to the pesticides on the market.

When cockroaches are found in an apartment in a residential building there is a risk of spreading the cockroaches, if you only exterminate locally. There must be an extermination strategy, and as a minimum the adjacent apartments must also be examined and treated if necessary.

In most cases, you should contact a professional company with an understanding of pest control, as cockroaches as mentioned can be difficult to exterminate. We will probably never get totalt rid of them.

The Oriental cockrach In Europe the Oriental cockroach (Blatta orientalis) is not nearly as common as the German. It is larger, grows up to 2.5 cm long and is shining black. the females have small elytra, while the elytra of the males almost cover the entire abdomen. Its way of life is largely as the German cockroach, but it requires higher temperatures to thrive. An important difference is that the female is not carrying the egg capsule around, but places it in the dark sheltered place. The capsule cracks after a few months and the small nymphs come out. This means that new cockroaches can appear months after the last adult is exterminated.

American cockroach The largest of those cockroaches that we occasionally encounter is the American cockroach (Periplaneta americana). Both sexes have elytra that are longer than the body. This cockroach is often introduced from overseas, and a few American cockroaches are lucky enough to escape to a place where it is hot and humid, perhaps in a heated greenhouse or conservatory, where they can survive, but under other conditions they will die quickly.

Clothes moths

Clothes moth

Clothes moth

Clothes moths belong to man’s oldest companions. In the Bible, they are used as an image of transitoriness, and our short lives are described as: “-clothes that are eaten up by moths”.

The small bronze-shining clothes moth (Tineola bisselliella) prefer hidden lives in dark corners, drawers and cupboards. They are poor fliers, and it is actually rare to have the opportunity to slap a clothes moth in free flight.

The female moth lays about 100 small, whitish eggs, which she tucks into folds or between threads in the fabric. The eggs hatch in a few days and the larvae immediately start to eat. At the same time they spin a fine, silken tube, that is adhesively put on the substrate. They can move in the pipe, and it can be extended when the larva has eaten all that it can reach from it Gnawed remnants and larval excrement sticking to the tube, and the presence of these webs is clear proof that it is the moths, and not other textile pests that have been gnawing.

The development from egg to adult moth lasts from one month to over a year depending on temperature, humidity and food quality. Under normal circumstances in our homes, there will be two generations per year.

Clothes moths thrive best at a temperature of 25 degrees C. This shows us that they originate from a warmer climate, and in Northern climates you will not find them outdoors.

Larval diet consists predominantly of horn substance (keratin) as they can find in wool, fur and feathers. It is one of the most non-digestible proteins, but these moths have special conditions in their guts so that they can digest these proteins. However, there are missing some necessary vitamins in it completely clean horn substance, so the larvae must have something else to eat in order to thrive, perhaps in the form of dirt of one kind or another in the clothes.

Clothes moths do not attack cotton nor synthetic fabrics, and as many fabrics today are treated against moths, the moths are not as common today as they were earlier, but there is still food enough for them in most households.
The female moths do not take food for themselves, and they are not like their larvae equipped with jaws to chew. This means that clean clothes in tightly closed bags of paper or plastic are effectively protected against moth infestations.

The extermination can in most cases be done by placing the infested goods in a freezer for a few days. Washing them in the washing machine will also effectively kill the eggs, larvae and adult moths. There are approved pesticides to exterminate clothes moth, and they are particularly suitable for treating cracks and fissures in closets, drawers and under the baseboards, which can hide larvae.

The case bearing clothes moth (Tinea pellionella) resembles the common clothes moth, their larvae, however, is easy to recognise. They spin a small tubular sheath, a casket which they occupy with wool and feather debris. They can, in contrast to the clothes moth larvae, crawl around with the rear body protected in the sheath. They have a tendency to move away from the place they have spent larval life when they are fully grown. If they have lived in a carpet, you can often see them crawling up the wall in search of a protected place for pupation, which happens inside the sheath.

The case bearing clothes moth has lower demands for temperature, and is a native, Northern European species which you, among other places, can find in birds’ nests. They are able to enter your home from the outside. They, however, require quite humid conditions, and do not thrive in dry rooms.

Otherwise their lives are a lot like that of the common clothes moth, and measures for prevention and control are the same.

Brown Carpet Beetle

Brown carpet beetle

Brown carpet beetle

The animal world is not static as nothing in nature is. Species disappear and others emerge.

The brown carpet beetle (Attagenus smirnovi) is one of the relatively new animals in our animal life. It is native to Africa. In Europe it was first discovered in 1961, when E.S. Smirnov (hence the species name) found a species in Moscow. A few years later a few brown carpet beetles appeared up in Herlev in Denmark, and now they have spread throughout Europe and has become common in many homes.

The adult beetle is only 3-4 mm long, the elytra covering the abdomen are brown while the front of the beetle is dark brown or black.

The female lay about 50 eggs, the larvae are yellowish-brown and clearly articulated and they have a brush-shaped tuft of hair at the rear.

Like most other carpet beetles, they eat dry remains of animals and plants. They are about six months to become mature and they can attain a length of about 8 mm. Brown carpet beetles are originally tropical animals and they grow best at a temperature of about 24 degrees C. and can not multiply outdoors in Northern Europe.
The adult beetles are active animals and good fliers. If you have brown carpet beetles in the house, you will often find them on window sills where they go looking for light. On summer days they fly in the open and like this they find their way from house to house, but they usually spread by being brought about in goods, luggage or furniture. In residential buildings, they can spread through piping and other crevices.

Given how common the brown carpet beetles are in European homes, it is remarkable how few actual damages have been reported over the years. Usually the larvae live hidden in cracks and crevices where they feed on random organic matter, dead insects, seeds and crumbs.

Several other countries have, however, seen the brown fur beetle as an actual pest that lives up to its name and gnaws fur, wool and feather. They have also been known to cause damage to museums where they among other things can ruin insect and herbarium collections.

It is very difficult to completely prevent the occurrence of the brown fur beetle, but normally a frequent, thorough vacuuming of cracks and crevices will keep the number down to a reasonable level. One of the pesticides that are approved for this purpose can of course also be used for treatment of their living spaces.

Carpet beetle

The, so to say, “true” carpet beetle (Attagenus Pellio), is slightly larger than its brown relative. It is plain black with a few white spots on its elytra. The larvae resemble the brown carpet beetle larvae, but they grow a little larger in size.

The carpet beetle is an old Danish species, and can be found in many places outside our homes. In summer you can see the beetles in blooming plants where they eat pollen and nectar.

Eggs are laid mainly in birds’ nests and mice nests where the larvae can live on feathers, hair and other debris. The beetles can also fly in from outside and lay their eggs directly on woolen fabrics and fur.

The greatest risk of getting them in, however, are from birds’ nests in attics. When discovering damage to textiles, the same methods are used as those against clothings moths and other carpet beetles.

Bed bugs

Bed Bug

Bed Bug

The adult bed bug (Cimex lectularius) is 4-5 mm. the body is oval and rust-red. It has no wings, which makes the abdomen clearly visible.

The bed bug is not a louse, but a kind of tick. Most ticks feed on plant sap, but the bed bug uses its sharp proboscis to suck blood.

About 75 different species of bed bugs are known, and it has been proven that they are all, in addition to the human, live on some birds and bats. That may seem a strange choice, but there is an explanation. Bed bugs do not live like the real louse on the body of the host. They live most of their lives in the environment of the host and they only occur on the hosts when sucking blood. Therefore they only survive with animals that have a nest or a home they continue to return to.

Evidence suggests that bed bugs originally evolved from bed bugs living on bats. One can imagine that when our ancestors, thousands of years ago, moved into caves, where bats already lived, bed bugs discovered that people were suitable hosts.

It must have happened in a warm area as bed bugs thrive best at temperatures between 25 and 28 degrees C. They can not survive if the temperature falls below 13 degrees C. The bed bug spread to Northern Europe when we started to have reasonably heated homes during the 1600s.
Bed bugs live in dark cracks and crevices as close as possible to the places where people sleep at night. They often live in the bed itself, but also behind loose wallpaper, behind pictures and wall hangings as well as under lists to name just a few possibilities.

Although it is not always possible to find living bed bugs in these places, they can easily be found by the presence of black droppings, empty white egg shells and empty hides.

Bed bugs come out at night, mostly attracted by body heat. They bite preferably on uncovered parts of the skin such as hands, arms, feet and neck, as opposed to fleas that often bites under close-fitting clothing. An adult bed bug eats 5-10 minutes and is then full. Then it pulls the proboscis back and crawls into hiding again. Here it sits and digests for a week until it gets hungry and crawls out from hiding again.

People respond very differently to bed bug bites. Some people have severe reactions while others do not react at all. It is estimated that about 10% of the population can be bitten every night without even noticing it, and it means that the stock can manage to grow wildly before the animals are discovered by accident.
One good note: It has never been proved that bedbugs spread diseases.

The female bed bug lays 4-5 eggs per day, totaling up to 200. She adheres them firmly to the ground in her hiding place. At room temperature, the eggs hatch in ten days. The small bed bugs resemble the adults. They shed their skin five times and must have a blood meal between each moult.

Bed bugs can live a few months without blood, and even longer if it is chilly. That explains why living bed bugs are found in houses that have been empty and cool for up to one year.

Bed bugs can travel from one apartment to another, for example. through piping, but they are primarily dispersed passively with furniture and luggage. One may be unfortunate enough to buy bed bugs along with recycled furniture, or to get them by taking things that might have been discarded due to bed bugs. even “nice” hotels can have problems and a common route of infestation is luggage that has been standing under the bed in a room with bed bugs.

If you suspect that bed bugs have slipped into your luggage it is a good idea to review it on return.
Clothes and other items that can tolerate it, should be washed in the washing machine or placed in a freezer a few days at minus 18 degrees C. Things that do not tolerate this treatment should be thoroughly inspected and optionally treated with an approved insecticide.

If you find bed bugs as a renter, you have a duty to report it to your landlord, who then has the responsibility to exterminate them.

If you own your home it is an advantage to have an experienced exterminator take care of the matter. Knowledge of habits and habitats of bed bugs is a prerequisite for a good result, and wrong treatment causes a risk for simply chasing the bed bugs to the neighbour.

Some birds and bats that may occur in our homes are also plagued by bed bugs, which in rare cases can seek into our houses and bite people. They resemble our own bugs to confusion.

The bat bug (Cimex pipistrelli) live in places where dwarf bats have their resting places. Bats sometimes settle in attics in residential buildings and then their bed bugs seek down and bite people. This happens especially if the bats for any reason disappears from the house and the bed bugs are left without their natural food source.

Pigeon bugs (Cimex columbarius) are very close relatives to the bed bug. They live in pigeon’s nests or in attics where some pigeons live, they can on rare occasions find their way into homes and then bite people.

Dermestes haemorrhoidalis

Dermestes haemorrhoidalis is a very close relative to the bacon beetle. The larvae are indistinguishable from those of the bacon beetle, but the beetles are distinguished by being black and they lack the bright bands over the elytra.

The dermestes haemorrhoidalis is unlike the bacon beetle not an old Danish species, and it has been introduced relatively recently, and is now common especially in properties in cities. Its way of life is similar to that of the bacon beetle. It thrives well in untidy companies and in apartments where offal is allowed to accumulate, but a small population of dermestes haemorrhoidalis can thrive near a dog’s or cat’s food bowl.

The main living space is often pigeons’ nests in attics.

When the larvae are ready to pupate they, like the larvae of the bacon beetle, tend to hide in cracks and crevices possibly gnawing into woodwork. One should therefore be aware that even after careful pest control and cleaning adult beetles can emerge for months if you have not found all the larvae during the pest control.

Bacon beetle

Bacon Beetle

Bacon Beetle

The bacon beetle is part of the dermestid beetles. There are about 25 species of dermestid beetles in Northern Europe. The bacon beetle is one of the best known. Most dermestid beetles feed on various parts of dead animals. They do not belong to the first wave of scavengers, but they arrive later and take advantage of the dry parts of the carrion. The bacon beetle is no exception and it belongs therefore to the group popularly described as “nature’s garbage collectors”, which ensures that carcasses are eaten and become a part of the circle of life.

It is an extremely important deed, but it is also something that can bring the bacon beetle in conflict with people because many of the foods we store correspond to dry carrion in the eyes of these beetles.

The adult bacon beetle (Dermestes lardarius) is 7-9 mm long and easily recognised by the bright band with dark dots that goes across the front of its elytra. The female lays hundreds of eggs, preferably directly in cracks and crevices in food. The larvae grow within 2-3 months, at room temperature, for a length of up to 15 mm. They are clearly articulated with long bristles sticking out from all joints. Visible on the rear part are the two dark chitin hooks.

In cold places, the bacon beetle overwinters as an adult beetle and becomes active again in the spring. The heated rooms is active throughout the year.

The full-grown larvae will usually leave the place they grew up and seek out a sheltered place where they can pupate. If they do not find a suitable spot close by they can chew a cave using their very strong jaws. This little cave is approximately 4 mm in diameter which is suitable for the larval thickness and a few cm. deep, and actually looks like it’s pierced with a 4mm. drill.

Like this they can cause secondary damage to cardboard and wood. This is the explanation as to why bacon beetles are sometimes found in places where they apparently do not belong. They simply gnawed into the packaging that stood near their food.

The bacon beetle used to be a feared pest in many households. It went into winter supplies as dried fish, cheese and smoked goods. Today, as these goods are kept more appropriately, the bacon beetle has only a tiny role in households.
In companies that work with dried fish, hides and dry food the bacon beetle and its close relative the Dermestes haemorrhoidalis still cause problems.

If a single bacon beetle appears in a house, it does not necessarily mean anything. They are active insects, and they fly in nature and can get lost indoors. If there are many, it is a good idea to find out where they come from. A dead mouse under the floor, a couple of dead chicks in a nest in the attic are options as to where the beetles come from. It also happens that they have evolved in a bag of dry dog or cat food containing all the things these beetles like to live in and eat. Foods that are forgotten because of illness or vacation are of course also an option