Technical Abstract: Although the sawtoothed grain beetle, Oryzaephilus surinamensis (L.), is an extremely destructive pest of processed consumer food products, there are few studies involving its behavior. The beetle is typically not believed to chew directly through packaging materials, though it might utilize openings or flaws in damaged or improperly sealed packages to gain entry. The behavioral mechanisms by which the sawtoothed grain beetle infests packages with flaws were investigated. Significantly more sawtoothed grain beetles infested consumer food packages that had been punctured with 0.4 mm diam. holes, to simulate packaging flaws that preclude adults, than when packages had no flaws. In a test arena, females laid more eggs into or near the hole in a plastic packaging film, when they were able to contact the food through the hole than when they could not contact the food. First instar larvae placed at either 1 mm or 1 cm away entered holes when food was present, indicating that packages could become infested if eggs were laid near holes. In the absence of food, neither adults nor larvae responded to holes. This study has shown the importance of sound packaging in preventing insect infestation.