Species Oryzaephilus surinamensis - Sawtoothed Grain Beetle

Oryzaephilus surinamensis (Linnaeus 1758)

see(1)(2)

The two Oryazephilus common in the US can be distinguished by a projection or bump just behind the eye. In O. surinamensis, this area is broad and blunt, and in mercator it is narrow and more protruding.

Left: O. surinamensis, right: O. mercator.

cosmopolitan(1) (spread by trade), of unclear origin(3)

primarily, granaries, grain elevators, flour mills, but capable to survive winter in temperate climes outdoors(1); adults have not been seen in flight, but they have been collected in light traps(4)

eggs laid singly or in small clusters in crevices in the food material during a 2-5 month period and hatch in 3-17 days; larva passes through 3-5 instars and makes a pupal cell attached to some solid object to pupate; typical life cycle takes 30-50 days; up to 7 generations per year; adults typically live 6-10 months (sometimes >3 years) (details in(4))

serious pest of stored grain; presence in household products is incidental and causes little concern(1); does not attack unbroken grain, but uses small lesions on the surface to gain entrance(4)