The golden spider beetle

Latin: Niptus hololeucus.
This spider beetle is studded with long golden hair. It infests the same types of products as the first two mentioned spider beetles. When occurring in a warehouse it is often because it has been able to eat dead insects, dry carrions or rodent droppings. The adult golden spider beetles do bite holes in woollen textiles. The beetles are shady, nocturnal, and are active in temperatures down to 5 ° C. The development time from egg to adult is one year at 15 ° C, and half a year at 18-20 ° C.

Plaster beetles

Latin: Clavicornia spp.

Plaster beetles

Plaster beetles

Season for plaster beetles

Season for plaster beetles

The name plaster beetle is an umbrella term for a part of the beetles of the genera Cryptophagus, Lathridius, Enicmus, Cartodere and Mycetaea. They are often considered as a group because they have a uniform biology, they are found in the same places and they all belong to the superfamily Clavicornia. Their outer antennae joints are developed as small clubs. Plaster beetles are quite small, only 2-3 mm long. Both beetles and larvae primarily live of mould and mildew. They are common in basements and storage rooms. In moist grain, straw and damp feed there can be found impressive amounts of plaster beetles. Moreover, they occur in all kinds of food that has gone damp and mouldy.

Lathridius minutus, squarenosed fungus beetle

Lathridius minutus, one of the most common mould beetles, can be quite abundant in mouldy hay.Lathridius minutus, one of the most common mould beetles, can be quite abundant in mouldy hay.

They are associated with the mites and booklice in mould fauna. They rarely do any real damage, but can occasionally damage dried fruit. Their presence is a warning that the product may have decreased in quality due to fungal growth and it may even be unhealthy to consume. Plaster beetles are exterminated and prevented by making sure that the product is dry and stored in a dry environment, or in short time so that the mould fails to make an impact. Chemical control of plaster beetles is quite meaningless alone, but may be an addition to drying products and storage rooms.

The smooth spider beetle

Latin: Gibbium psylloides

The shiny spider beetle

The shiny spider beetle

Shiny spider beetle

Shiny spider beetle

The smooth spider beetle lacks hair and is rather reminiscent of a small glass drop that moves slowly around on its long legs. It occurs as a grain pest in warm countries such as India. Like the other spider beetles it can live of a wide range of dry animal and vegetable substances. It is sometimes imported with spices.

Skin beetles

Skin beetles are consistently strong, arched beetles with oval or round body shapes. The surface is almost always covered with small, coloured hair or dandruff, which provides distinctive drawings. The larvae are covered with long hair of various kinds. Some of the hair is the cause of skin irritation in people. They feed primarily on the dry remains of plants and animals. Some of the skin beetle larvae belong to the carrion fauna. They first appear in carrion when maggots and others have eaten most of the meat. Skin beetles eat cartilage and dry meat leftovers. Some skin beetles can also digest hair and feathers.

The saw-toothed grain beetle

The saw-toothed grain beetle

The saw-toothed grain beetle

Season for merchant grain beetle and saw-toothed grain beetle

Season for merchant grain beetle and saw-toothed grain beetle

Latin: Oryzaephilus surinamensis.

2.5 – 3.5 mm long, slender and brown-black. The distinctive features are the serrated growths on the prothorax side edges just behind the head. It cannot infest whole, undamaged kernels and it mainly eats seeds. In goods of cereal origin, flour and grain in particular, it is one of our most common pests.

Eggs are laid loosely in the grain or food. Each female lays 6 to 10 eggs per day up to 375 in total. The white, flat and very active larvae feed on the same foods as adults and they are hardly ever seen. Saw-toothed grain beetles like heat and cannot reproduce when the temperature falls below 18 ° C. It is rarely hot in cereal storages and the saw-toothed grain beetle is practically only found in grain that already contain granary weevils. In such goods, weevils provide heat and damaged kernels which make it possible for the saw-toothed grain beetles to develop.

Adult, pupa and larva of the saw-toothed grain beetle

Adult, pupa and larva of the saw-toothed grain beetle

The optimal temperatures, which gives the shortest generation time is 31 to 34 ° C. At these temperatures, the number of the saw-toothed grain beetle in a population is increased by up to 50 times the original number within a month. In, for example, Danish grain storages, the species is not difficult to exterminate, but in England malathion-resistant populations have been known to cause difficulties.

Grain beetles

Elongated small beetles, 2 – 3.5 mm long. The saw-toothed grain beetle, the merchant grain beetle and the rust-red grain beetle are primarily of interest. In addition to these, a large number of less known grain beetles exist, which are rare in Europe, which include Cryptolestes minutus (commonly known as the flat grain beetle or the biscuit beetle), Ahasuerus advena and the species Cathartus quadricollis. The latter acts as a grain storage pest in the southern United States, but is not known to live in Europe. None of the above mentioned grain beetles live in the wild in Northern Europe.

They require fairly high temperatures in order to develop and they are tolerant to humidity levels as low as 10% RH. It is assumed that these beetles are supplied to us with imports from warm countries and they can survive in grain stores with hot pockets and in warm rooms in general. The extermination should not cause problems. Grain beetles can be controlled in the same way as weevils and they are even easier to exterminate with poison in grain stores because the larvae live in the seeds.

Larder beetle larvae hairs.

The carpet beetle larva

Fig. 29. The carpet beetle larva has nasty hairs on the abdomen. (Peterson)

Many of the beetle larvae that are common in Denmark, especially the larder beetle larvae (Dermestidae), have very crafty hair. Some larder beetle larvae have spines on their tale end. The spines end in something that resembles a harpoon with 4-6 long barbs and along the shaft are 30-40 shell crests of barbs facing upwards. If larder beetle larvae feel threatened by other bugs, they turn the tail against the attacker and put up the spines. This usually results in some of them being ripped off. This troubles the attacker and can even lock the attacking animal’s limbs together so that it succumbs.

Hair from larder beetle larva can also penetrate human skin. This might happen when you’re lying on a mattress, which has been visited by carpet beetles (Anthrenus spp.) or if other larder beetles from bird nests or food will find their way to clothing or furniture with which humans have contact. On the skin, a dark spot appears.

It is the larder beetle larvae hair or a part of it. First, a red, irritated area will appear around the hair. Next, is a small, clear blister will appear. The blister may turn yellow after a few days (inflammation). Inflammation can sometimes be avoided, if the hair is pulled out using a needle and tweezers, however, it is not always possible.

Eradication. First, try to find out where the larder beetle larvae are coming from and either fight with poison or keep them out. Then, attempt to remove the larder beetle larva, their empty skins and loose hairs. Repeated vacuuming can do the job.

Beetles

Skin beetle and larva

Skin beetle and larva

Both adult beetles and their larvae have biting mouth parts. They can bite if you get them under your clothes or squeeze them. However, this rarely happens. The only Danish species, which bite humans on its own initiative, is the seven-spot ladybird, Coccinella septempunctata. Usually, this only happens, when the ladybirds are quite numerous and their natural food supply of aphids and scale insects run out. Some of the hungry beetles may want to try a sample of humans. Beetle bites usually do not have any after-effect because no poison, etc. is injected to the wound.

Butterflies and beetles

Butterfly

Butterfly

Butterflies (Lepidoptera) and beetles (Coleoptera) are the animal orders which are richest in species. 140,000 different kinds of butterflies and 350,000 kinds of beetles are known, and a huge number of new species from the tropical rain forests are waiting to be discovered and described. Despite there being so man are no known blood-sucking butterflies or beetles. The skin symptoms, one can get from these animals is partly caused by defense mechanisms against their natural enemies.

The masked hunter

Masked hunter

Fig. 23. Masked hunter are mostly common during the summer season.

The masked hunter

The masked hunter

The masked hunter, Reduvius personatus, is primarily found on attics, in outbuildings and similar places. The nymphs secrete a sticky substance which causes dust and dirt to stick to them. The adult masked hunter, on the other hand, is shiny, brownish animals. They are 1.5 cm long. Masked hunters are predatory insects and feed on other insects, which intestines they suck out. There are examples of people being bitten while sleeping or the bugs have bitten in self-defense. The bite is painful and the skin reaction is rather strong.

In housing with bedbugs, there are sometimes a lot of masked hunters, which feed on the bed bugs. However, usually the masked hunters that are occasionally found inside are individuals who have strayed from their natural hunting grounds

Masked hunter

Masked hunter

It is rarely necessary to perform an actual eradication. If large numbers of masked hunters are found, for example, out from the cracks to a roof slope, the bugs can be eradicated with an insect powder.

Masked hunters are present in all seasons, however, they are mostly seen in the period from June to August.