American black flour beetle
Tribolium audax Halstead

Order: Coleoptera
Family: Tenebrionidae
Acronym: TAU

Ecology

The American black flour beetle is found in temperate regions. It is widely distributed through Canada where it is occasionally found in empty granaries in the Prairies. It feeds on cereal grains, flour, meal, seeds and cereal products. It is most similar in appearance to the European black flour beetle, Tribolium madens. The American black flour beetle is found more often than the European black flour beetle. This species does not normally infest stored grain. It can survive in unheated storage in milder-climatic regions.

Damage

The American black flour beetle is a minor pest. The adult and larva are general feeders. Damage is not distinct. It is sometimes found in packaged foods. Occasionally it has been found infesting flour mills in the northwest of the United States. A sign of infestation is a disagreeable odour in the commodity.

Life history

The adult is dark brown to black. It is 2.8 to 4.5 mm long. It is oval and elongated. The adult has dense pits on the surface of its head which meet between its eyes. It has a rounder eye than the European black flour beetle. Adults live on average for 2 – 3 months, although they are reported to live up to 3 years in temperate conditions.

The female lays eggs up to 1000 eggs at random, loosely in the food source.

The larva is cylindrical and dark brown in color. It is active. It may eat smaller insects and other larvae. The optimal temperature for development is 32°C, and a relative humidity ranging from 50% to 72%. Under these conditions the development time ranges from 41 to 80 days. The larva pupates in the food source.

Control

Controlling insect infestations

Images

Adult American black flour beetle