Adults

Yellow mealworm adults look like typical beetles, and are not worm-like in appearance as their common name suggests. They are dark in color, have a hard shell and are about ½ inch long.

Larvae

The common name mealworm comes from the appearance of the larvae (caterpillars), which are cylinder-shaped and about an inch long when full grown. Their coloration is yellow with brownish rings on the body segments. The larval body turns progressively harder as they grow.

Diet: What Do Mealworms Eat?

Mealworms are categorized as secondary stored product pest. This means they primarily feed on materials that are damp, decomposing and moldy. Their preferred food sources are items such as leaves, dead insects, animal wastes and moist stored grains or grain products that are in the process of decaying. Homeowners may find mealworms in oatmeal, flour, or other dry goods stored in the pantry.

Habitat: Where Do Mealworms Live?

Their normal habitat is dark, cool and moist locations where there is suitable food and sheltered areas such as under rocks, logs, in animal waste accumulations and in moist, stored grain storage areas.

Reproduction & Life Cycle

Mealworms go through an egg, larval, pupal and adult stages (complete metamorphosis) and their life cycle usually is completed in about three to six months. Adult mealworm beetles only live about 30-70 days, depending on the temperature and suitability of their habitat. Read more .