The brown carpet beetle, also known as the vodka beetle, was introduced to Britain in the 1970s and is becoming more common as a pest of natural history collections and a minor household pest.
Identification
Adults have oval bodies 2-5 mm long and 2-2.5 mm wide, with a black base colour and dense hairs giving brown to reddish-yellow elytra (wing cases). The head and top part of the thorax (the beetle's middle section) are dark red-brown to black. The antennae and legs are reddish to yellow. Males have a very long last (11th) antennal segment, four times the length of the previous two segments together. The females are larger than males, with shorter antennae. There is one ocellus (simple eye) visible in the middle of the head.
The larva of the brown carpet beetle is up to 8mm long when fully developed, torpedo-shaped, tapering from head to the end of abdomen, which continues with two brush-shaped tufts of hair. It superficially resembles a very dark silverfish. The segments are very visible, which give the larva a banded appearance, with darker stripes wider than the lighter ones. Its colour is bronze-brown upperside and yellowish-brown underside, with golden yellow hairiness and a scaly pubescence of the same colour on thorax and abdomen segments. The larva avoids light. Larvae of other Attagenus species are very similar.
Distribution and habitat
The beetle originates from East Africa, from where it was accidentally imported to Russia where it was first observed in 1961. From there, it spread to different parts of Europe, including Britain. It was found here first in a small area around London, but it is now becoming more common in England.
It is a pest of natural history collections and a household pest. In nature it lives in birds’ nests and bats’ roosts, but it has became a synanthropic species, meaning it prefers to live in and around human dwellings. It has been recorded living on carpets, fluff on floor and on dead dry insects. It has also been found living in stored products in Africa and Europe. The larvae feed on a variety of materials containing keratin, such as wool, fur, hide, feather, etc. It is a warmth-loving species, so it depends on central heating for survival in Northern Europe.
Life cycle
The adults can live without feeding, but the larvae depend on dry substances of animal origin to develop.
The optimal conditions for the development of Vodka beetles are: 24°C temperature, 70-80% relative air humidity and plentiful food supply. In these ideal conditions, the female lays 30-50 eggs in small holes or other hiding places, the eggs hatch in 10 days, the larvae complete their development in 3 months after which they pupate and then emerge as adults in 8-13 days.
In real situations, the development may be much slower, the life cycle varying from 6 to 18 months. The larva molts its skin 12 times during the whole cycle. In permanently heated premises in Europe both adults and larvae can be found year round, but adults are more common from March to September.
Damage and control
The adult beetles are mostly diurnal (active during the day) and mobile, being able to fly and colonize new areas. They are often found on windowsills, seeking light, and also seeking food sources for the larvae, where females will lay their eggs.
The signs of brown carpet beetle infestation are damage to museum specimens, carpets, clothing, etc. and the frass (the larvae's extrement) resulting from feeding. The skins caste off by larvae after many molting events are another sign.
The damage is done by the larvae, which attack various organic materials containing keratin. Serious damage occurs when there is a massive, undetected infestation which can destroy entire museum collections or stored clothing and carpets. Stored food may be contaminated by excrement.
Preventing an infestation is the best way to avoid damage. Brown carpet beetles can be monitored with sticky traps, pheromone lures and larval food monitors. Quarantine is an important preventative measure when moving objects between collections or houses. Maintaining a strict hygiene by cleaning and removing potential food sources like fluff, feathers, etc. from inaccessible places such as between floorboards will prevent an infestation. In museum collections and storage facilities, maintaining low temperature and air humidity will prevent or slow down larval development.
If an infestation has occurred, it can be controlled by physical measures such as discarding infested items, vacuuming and brushing. When possible, deep freezing specimens or infested objects should be carried out to kill larvae and eggs.
Chemical control involves application of insecticide, fumigating, gas treatment, etc.
More information
Download this information as PDFs:
Elsewhere on the internet:
- Royal Entomological Society Handbooks for the Identification of British Insects Vol. 5 Part 3. Adults and Larvae of Hide, Larder and Carpet Beetles and their relatives (PDF 1.69MB)
- Info sheets from MuseumPests.net:
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