Meal Worms in Semolina Flour

Mealworms are the larvae of the darkling beetle, a dark brown or black insect about half an inch long that lives on or in cereal grains like semolina flour and frequently infests poultry houses where the birds are fed grain-based feeds. Mealworms are also grown purposely by individuals and pet food companies, since they are valuable as food for aquarium fish and exotic reptiles.

  1. Mealworms as Pests

    • Mealworms can infest semolina flour and other grain-based products in the home or in storage facilities. A single female darkling beetle that gains access to a container of flour can lay up to 275 eggs, which hatch into mealworms within two weeks. In the event of a mealworm infestation in the home, discard the infested flour, inspect and store uninfested flour in tightly sealed, insect-proof containers. Vacuum the kitchen cabinet to capture stray mealworm larvae and adult beetles.

    Growing Mealworms on Semolina

    • To grow mealworms on semolina flour for pet food, choose a box at least 8 inches deep and about 18-by-24 inches wide. Nail or glue a 2-inch-wide rim of smooth sheet metal around the inside walls near the top of the box to discourage worms and adult beetles from climbing up the walls and escaping. Fill the box with several inches of semolina flour or any other finely milled grain.

    Preventing Bedding from Packing

    • The semolina flour in the box acts as both bedding and food for the beetles and their larvae. Since flour, by itself, has a tendency to pack tightly, it's best to add some wheat bran or middling along with some crinkled-up paper or cloth to keep the bedding loose. Otherwise, the mealworms have difficulty making use of the flour underneath the surface, slowing growth and increasing competition for the available food.

    Providing Moisture and Ventilation

    • Like most animals, mealworms need a bit of moisture to grow. The easiest way to provide water in a usable form for the larvae is to throw a few slices of apple or potato into the box, and change them whenever they dry out or start to spoil. Tie cheesecloth over the top of the box rather than using a lid; this will allow for good ventilation while still keeping adult beetles contained.