Sawtoothed Grain Beetles

Behavior and Habitat of Sawtoothed Grain Beetles

The Sawtoothed Grain beetle is a scavenger and can not fly. Adults and larvae are external feeders, feeding on finely divided food particles and not whole grains. Large populations of this beetle can develop quickly, forcing adult beetles to seek new food sources. They have been known to invade every package or food stored near an infested food product. Sawtoothed Grain beetle adults usually live about 6 to 10 months, with some living as long as 3 years. Females usually emerge in April and lay an average of 300 eggs. Egg laying begins about 5 days after emergence and continues up to 3 to 4 weeks. Eggs hatch in about 8 days, larvae mature in 37 days, and pupa about 67 days. They prefer cereal-based products. The Sawtoothed Grain beetle is common in stored-food products such as cereal, cornmeal, cornstarch, popcorn, rice, dried fruits, raisins, flour, pet foods, bran, macaroni, sugar, and bread. They are capable of chewing into unopened paper or cardboard boxes, through cellophane, plastic, and foil wrapped packages. Once inside, populations build up rapidly often spreading to other stored foods and into food debris accumulated in the cupboard corners.