Substantial numbers of grain-infesting insects can reduce the value of grain or render it unfit for processing or feeding. Results of feeding by sawtoothed and merchant grain beetles can reduced grain weight and quality. The presence of live insects can result in dockage or rejection of the grain. The habits and development of the two species are similar. The adults of the sawtoothed grain beetle, on the other hand, cannot fly and must be introduced from contaminated grain.
Adults live an average of six to ten months, but can live as long as three years.
The females lay between 43 and 285 eggs during their lifetime. Eggs are dropped loosely among grain kernels or tucked into a crevice in a kernel. The larvae emerge and crawl freely about the grain to feed on broken kernels. Larger larvae may tunnel into kernels to feed. Larvae mature in about two weeks, and construct cocoon-like coverings by joining together small grains or pieces of grain.