Black carpet beetle
Attagenus unicolor (Braham)

Order: Coleoptera
Family: Dermestidae
Acronym: AUN

Ecology

The black carpet beetle is found worldwide and it is one of the most commonly encountered minor stored product pests. In Canada, it is widely distributed. It is found in grain storage in grain dust, debris and in spilled grain. It is a scavenger and feeds on dried animal and vegetable material. It is also found in households feeding on wool articles, some synthetic fibres, cereal products and dried dog food. It can overwinter as an adult or larva.

Damage

The black carpet beetle is a minor pest of stored grain. The larva damages products by feeding and burrowing in infested materials. It feeds on cereal and processed products including barley, peanuts, bran, ground maize, and alfalfa meal. Signs of infestation include holes in the commodity and contamination of the product with cast skins. The black carpet beetle is also considered to be a pest in museums where it attacks organic artifacts, such as hides, furs, insect specimens, wool articles and oilseeds.

Life history

The adult black carpet beetle is uniformly black and covered in dark or gold brown hairs. It is oval and 2.8 to 3 mm long. It has a median ocellus on the top of its head, which looks like a small, hairless circular bump. The adult has a short lifespan, surviving for only a couple of weeks to a couple of months. Adults fly and also feed on nectar and pollen.

Ideal breeding conditions are temperatures between 15°C and 30°C. The female lays eggs in crevices in the material that it infests.

The larva is reddish-brown in color It is cylindrical with a well-defined head and legs. When full grown it is about 6 - 8 mm long. The larva is covered in dense brown-gold hairs. It has a tuft of long brown hairs at the end of the abdomen that resembles a tail. The larva pupates in the last larval skin. Developmental temperatures range from 22°C to 25°C. Under those conditions it may take a larva 9 – 24 months to develop. Under ideal conditions of 24°C and a relative humidity of 70%, development occurs in 8 months. When exposed to cooler temperatures, the larva can enter diapause.

Depending on food and temperature conditions the entire life cycle can take from 8 months to 3 years to complete.

Control

Controlling insect infestations

Images

Drawing of an adult black carpet beetle.

Clemson Univ./USDA CES, Bugwood.org
Adult black carpet beetle.

Clemson Univ./USDA CES, Bugwood.org
Black carpet beetle larva.