Mottled dermestid beetle
Trogoderma inclusum LeConte

Order: Coleoptera
Family: Dermestidae
Acronym: TIN

Ecology

The mottled dermestid beetle is found throughout the northern hemisphere in North America, Europe and North and Central Asia. In Canada, it is widely distributed and it is one of the most common species of Trogoderma found. It infests processed dry foods and animal feeds. It is a pest in flour mills, dried milk factories, processing plants and storage facilities. It is found in stored seed, grain, wheat, corn, sorghum and nuts. The mottled dermestid beetle looks very similar to other Trogoderma species.

Damage

The mottled dermestid beetle is a generalist feeder. The damage is not distinctive and is caused by larvae feeding. The larva causes damage by eating the germ and will consume whole kernels. A sign of infestation is contamination of the commodity with cast larval skins.

Life history

The adult is bicoloured. The elytra have an irregular pattern of light and dark coloration. It is covered with light and dark brown hairs. It is oval and has clubbed antennae. It is 3.5 mm long. It can be distinguished from other Trogoderma species by the distinctive notch in the inner margin of its eye. It is short-lived and lives, on average, between 10-40 days. The adults can fly and it feeds on nectar and pollen from flowers.

Adults mate immediately after pupation. Ideal breeding conditions are temperatures between 20°C and 40°C. The female is larger than the male. She lays her eggs singly near the food source.

The larva is oval shaped and covered in dense hairs. It is whitish yellow when young and reddish brown when mature. There are tufts of short dense hairs located on the last abdominal segments. With an ideal temperature of 30°C, the larva can develop in 60 days. The larva moults many times during development. Under adverse conditions, it will moult even more. It can enter a state of diapause if the environment is unsuitable for development. The larva pupates in the last larval skin.

Control

Controlling insect infestations

Images

Mottled dermestid beetle