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Michigan State University Extension
Home Maintenance And Repair - 01500532
06/24/03

Mealworms



Two species of mealworms, the dark mealworm and the yellow mealworm occur in Michigan. The dark mealworm occurs throughout the U.S., while the yellow mealworm is absent from the southern states.

Mealworm adults are robust, slightly flattened, 3/4 - 1" long beetles. The dark mealworm adult is a dull, black color, while the yellow mealworm adult is a shiny, polished dark brown or black. Mealworm larvae are shiny, smooth, hardened "worms." They have three pairs of segmented thoracic legs, and two short, horn-like appendages on the tip of the abdomen. Full grown larvae are 1 - 1 1/4" in length. Dark mealworms are dark brown; yellow mealworms are honey-yellow in color.

Mealworms overwinter as partially grown larvae. The overwintered larvae complete their development in the spring, pupate, and emerge as adults during the summer (mid July to early August in Michigan). Adults live for 2 to 3 months. After mating the females deposit 275 to 500 eggs, either singly or in small batches. The eggs are deposited in areas where the larvae will find ample food. The eggs hatch in about two weeks. The larvae feed and grow over a period of 6 to 9 months (as long as 20 months in some cases), molting a total of 14 or 15 times. Mature larvae are active and wander in search of pupation sites. Due to this habit they may be found in any area of the home. The complete life cycle, therefore, requires 6 months to 2 years for completion. One generation per year is normal.

Mealworms are scavengers and are most commonly found in damp, spoiled grain and grain products. Adults and larvae hide in refuse, sacks, bins, grain and similar undisturbed situations. Adults and larvae are also found in cereal products, macaroni, meal, bran, meat scraps, feathers and dead insects.

Mealworms are popular as fish bait and as food for many types of small pets. They are easy to raise and there is information available on this subject. Mealworms also show great potential as a source of protein for human nutrition.

Mealworms are seldom a serious problem in homes. Control should begin with a search for spoiled and infested grain and grain products. Remember to check bulk storage items (for example, dog food or bird seed). Also, it is necessary to locate any accumulations of crumbs and other food material behind appliances and in upholstered furniture. Keep in mind that both mature larvae and adults wander and may be found a considerable distance from the source of the infestation.

Integrated Mealworm Management

Location of the infestation, followed by destruction of any mealworms found, will generally control an infestation.

For a complete listing of suggested control options for all home, yard and garden insect pests contact your local Extension Service, found under local government in the phone book.

Read and follow instructions on the pesticide label. Heed all warnings. Check with your physician if you have any concerns regarding your personal health risk.

References

Revised by Tom Ellis, M.S., Department of Entomology

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MSU is an affirmative-action, equal-opportunity employer. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

This information.was reviewed as of June 2008.  For more information about the contents please contact costner@msu.edu for webpage problems strausc@msu.edu .