Mealworms overwinter as partially grown larvae. 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.
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.