There are a number of carpet beetles in the Destermid family, most are invasive, but there is one native species, the Australian carpet beetle, Anthrenocerus australis.
Another member of the demestids family is the khapra beetle, one of the most significant stored product pests globally. The larva and adult can easily be mistaken for carpet beetles. It is not currently in Australia, but there have been a couple of recent incursions.
Carpet beetles are found across Australia and worldwide.
As a fabric pest, carpet beetles are more tolerant of lower humidity and so can be found in both inland and coastal areas. (Clothes moths prefer a more humid environment and so are found mainly in coastal areas).
Carpet beetles are perhaps the most significant fabric pests eating a wide range of fabrics affecting clothes, carpets, curtain, upholstery and more. They can also be a significant pest of stuff animals in museums.
In Australia there are three key carpet beetles: the Australian carpet beetle (Anthrenocerus Australis), the similar, variegated carpet beetle (Anthrenus verbasci) and the larger black carpet beetle (Attagenus unicolor). The variegated carpet beetle is probably the most commonly encountered.
It is the larval stage, also called the ‘woolly bear’ as a result of its hairy appearance that does all the damage. The larvae can be up to 8mm long (bigger than the adults). They can be hard to spot as they tend to find in dark, undisturbed places. As the grow, they moult, leaving behind their hairy skins, which can cause irritation for some people.
The adults live outside and feed on the pollen from flowers. The variegated and Australian carpet beetles are up to 3mm long, with the black carpet beetle larger and more elongated, up to 5mm long.
Carpet beetles go through complete metamorphosis, with egg, larva, pupa and adult stages.
Females can lay up to 90 eggs, which hatch within 2 weeks. They may remain in the larval stages for a year or more depending on the conditions (generally the warmer the temperature the quicker the life-cycle), however a more typical duration is between 2-9 months.
The main pest species – the variegated and black carpet beetles tend to have one generation a year, with the larvae tending to pupate in late winter with the adults emerging in spring. However, some species can have more than one generation a year. Adults themselves tend to live for only 2 weeks or so.
Carpet beetle larvae feed on animal fibres such as wool, fur, silk, feathers and leather. They are one of the few insects that can produce enzymes to digest keratin, the protein found in animal hair. They will also feed on a range of dry foods.
In the natural environment, carpet beetles will eat dead animal carcasses. So often the source of an infestation inside the house may be from a dead rat or possum in the roof or sub-floor.
The adult beetles feed on pollen from flowers, which is why they are often found on window sill – trying to get out after pupating inside.
Damage: They will chew irregular holes in fabrics. In carpets the damage will be in the dark, undisturbed areas such as under heavy furniture and along the edges of carpets and rugs, as the larvae will often hide and feed from underneath.
The larvae may be hard to spot, but they shed, hairy skins can build up in areas of activity. These hairy skins can cause irritation in some people so shouldn’t be picked up. Their droppings, which are the size of coarse sand (and likely the colour of the fabric on which they are feeding), will also be found at the feeding sites.
Adult carpet beetles on the window sill trying to get out are a sure sign of an infestation somewhere inside the house. Although the adults appear in spring and throughout summer, the larvae will be active (and eating your fabrics!) all year round.
To successfully get rid of carpet beetles, it is necessary to find all the sources of infestation.
This can be a challenge for homeowners, so often it is better to engage a professional pest manager.
It is also suggested to avoid having wool insulation as this can also provide a food source for carpet beetles.
More information on carpet beetle treatments.