Grain weevil (Sitophilus granarius)
The grain weevil is a snout beetle 3 to 5 mm long, red-brown to black-brown depending on age. This species is flightless and lives mostly in grain stores, where it feeds on grains of all kinds. The female eats a hole in a grain, lays the egg in the hole and secretes a substance to plug the opening. The entire developmental process from egg to larva to pupa then takes place inside the grain, unseen from the outside. The grain is consumed nearly completely from the inside.
The grain weevil is the most important stored grain pest in temperate climate zones. The enormous reproductive capacity of these beetles results in larval feeding damage that can be so extensive that stored crops cannot be sold and must be destroyed. Infested grain heats up, becomes musty and is additionally infested by follow-up pests such as bacteria, fungi and mites.