Class: Insects
Size: 10 to 18mm
Weight: Variable
Age: Larvae: 6 to 12 months, beetles 6 weeks
Appearance: Reddish brown to black colouration
Food: Cereals
Distribution: Worldwide (crop follower)
Sleep-wake rhythm: Nocturnal
Original location: Europe, West Asia
Habitat: Bark of rotten trees, bird nests, grain silos, storage rooms
Natural enemies: None
Threatened with extinction: No

• The larvae of the mealworm beetle are called mealworms because of their worm-like appearance. Beetles and larvae are storage pests, larvae are also bred as food for terrarium animals.
• The mealworm beetle, especially its offspring, the mealworms, are very unpopular as grain pests. Beetles invade houses and mills and lay their eggs in granaries, flour and cereal-containing foods. Mealworms can cause great damage, they eat large quantities and their excrement makes the food inedible.
• Mealworm beetles are widespread throughout the world and are one of the most commonly carried pests. Outdoors, they and their larvae inhabit mud, rotting wood and birds’ nests. They inhabit flour and other grain products near humans and like to stay in dark and warm places.
• The nocturnal mealworm beetles feed on cereals, flour, bakery products and other starchy substances. They are therefore often found in bakeries, but this does not necessarily indicate a lack of hygiene.
• They also eat other insects and sometimes their own larvae. During the day, they prefer to hide in dark crevices. The beetles can fly, but rarely do. Larvae, like beetles, feed mainly on starchy substances, but also eat conspecifics in the larval and pupal stages, and their remains left behind by moulting.
• In Europe, mainly in the Netherlands and Belgium, mealworm larvae are bred as edible insects for human consumption. In Switzerland, mealworms in the larval stage have also been permitted as food since 1 May 2017, in addition to crickets (Achetadomesticus) and migratory locusts (Locusta migratoria).