Pest fact sheet 1: Varied carpet beetle

This fact sheet can be used for identification of the varied carpet beetle should your collection become affected by pests. Included below are photographs of the adult and larva and information on the life cycle, how to spot signs of damage and the materials likely to be affected and similar species of pest.

Latin name: Anthrenus verbasci

Identification:

The adults are small round beetles covered with grey and gold scales. They have a prominent head with clubbed antennae. Adult size: 2 mm-3 mm long.

Magnified image of an adult carpet beetle and an illustration next to it
The adult carpet beetle

The larva are short and fat with bands of darker hairs. Often called ‘woolly bears’. Larvae size: 0.5 mm-5 mm long.

Magnified image of a carpet beetle larva and an illustration
The larva of a carpet beetle

Life cycle

Adult beetles fly well in warm weather and may frequently be found on window sills. In the UK they are often found outside in late spring and early summer where they mate on flowers, such as hogweed and spirea.

Females lay batches of eggs secreted in cracks and crevices. When the larvae first hatch they are extremely small, less than 0.5 mm, and they can gain entry to cupboards and drawers through very small cracks. When they are larger, they will wander around and may attack more than one object.

The larvae may take 1 or 2 years to complete their growth and each new cycle starts after they pupate and change into adults in the Spring.

Signs of damage

As the larvae grow, they leave empty hairy cast skins, or husks, which may be the first signs of beetle attack.

Three carpet beetle husks that have been shed by the larvae
Carpet beetle husks

They produce pellets of excreta, called frass, which may be found under or near infested objects.

A small pile of frass from carpet beetle excreta
Frass from carpet beetle excreta

Materials damaged

The larvae are voracious feeders and will rapidly make neat holes in woolen textiles, animal specimens, fur and feathers.

A piece of red woolen material showing damage holes from being eaten by a carpet beetle
Damage to textiles by a carpet beetle

They will also graze on animal glue in book bindings and picture frames. Clean cotton materials are not normally attacked, although larvae may bore through this on their way out of a feather cushion.

Special points

Carpet beetles are often found in natural situations such as birds’ nests, wasp nests and animal burrows. Once established, they can be difficult to eradicate because the larvae can forage widely and may take some years to complete development.

Similar species: Guernsey carpet beetle Anthrenus sarnicus, Carpet beetle Anthrenus fuscus (See pest fact sheet No 12)

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Date created: 2010

Author: David Pinniger

Publisher: Collections Trust