Glass Plates filled with packed Flour (GPF). This artificial system aims to mimic the compactness of the cereal grain. It consists of filling the space between two glass plates, separated with 1.5 mm-thick spacers, with wheat flour. Weevils are individually deposited between two layers of packed wheat flour and transferred to the incubator (27.5°C and 70% relative humidity). This protocol could be adapted to an Eppendorf vial system.