Mealworms, Tenebrio molitor, Wikimedia file CC attribution, photo by Tiia Monto.
Common Name: Mealworm, Yellow Mealworm
Scientific Name: Order Coleoptera, family Tenebrionidae, Tenebrio molitor
Size: Adult—1/2" to 1", larva—1" to 1 1/2"
Identification: Male and female mealworms look alike. Adults are flattened black beetles. Larvae are white when hatched but become yellow and resemble wireworms.
Biology and Life Cycle: Female beetles deposit whitish oval eggs from 1 to 1,000 in food materials. Eggs hatch in four to eighteen days. Larvae live for six to nine months and usually overwinter in this stage. Pupal stage is white and is passed without any cocoon or protective covering.
Habitat: Damp grains, especially grains that have been undisturbed for some time.
Feeding Habits: Feed in and around grain bins, especially in dark places where the grain has not been disturbed in a long time. Mealworms like meal, bran, meat scraps, feathers, and dead insects.
Economic Importance: Destruction of food products.
Natural Control: Moving and disturbing the grain from time to time.
Organic Control: Diatomaceous earth in grain.
Insight: Mealworms are sold as a food source for insectivorous pets such as hedgehogs and reptiles.