Bug FAQSawtoothed Grain Beetle
Oryzaephilus surinamensis · Order: Coleoptera · Family: Silvanidae
Also called: Saw-toothed Grain Beetle, merchant grain beetle
Source: Wikipedia
The sawtoothed grain beetle is a small, dark brown insect about 2.4 to 3 mm long with tiny tooth-like projections on its thorax. It lives in stored grain, pet food and seeds in homes, stores and factories, feeding on broken grain pieces and sometimes boring into kernels. Adults can survive many months, up to three years, and may occasionally nibble skin without causing injury.
Source: Wikipedia
How to recognize it
The beetle is slender, dark brown and shows tiny teeth along the side of its front segment.
Source: Wikipedia
Size
Adults measure between 2.4 and 3 mm, while larvae grow up to about 3 mm.
Source: Wikipedia
Does it bite or sting?
In heavy infestations adults have been observed to nibble human skin, though the bites cause no harm.
Source: Wikipedia
How to get rid of it
Keeping dried foods in sealed containers helps prevent infestations at home.
Source: Wikipedia
Where it lives
It is a common pest of stored products, found in food factories, warehouses, retail stores and home pantries.
Source: Wikipedia
What it eats
Adults crawl over food masses and eat broken grain or damaged kernels; larger larvae can bore into whole kernels.
Source: Wikipedia
Life cycle
Larvae shed their skin two to four times before turning into pupae.
Source: Wikipedia
When you see it
Adults typically live six to ten months, but some can survive up to three years.
Source: Wikipedia
Where it comes from
The species name means “rice-lover from Suriname,” reflecting its original description by Linnaeus.
Source: Wikipedia
Lookalikes
It looks almost identical to the merchant grain beetle, but has smaller eyes, a broader triangular head and cannot fly.
Source: Wikipedia
Where it is found in the US
Recorded in 37 of 51 states and DC. Most records: Kentucky, Alaska, Pennsylvania, Colorado, Illinois, Texas, Michigan, Florida.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Do sawtoothed grain beetles bite people?
They may nibble skin when numbers are high, but the bites are harmless.
Source: Wikipedia
How can I stop them in my pantry?
Store all dried foods in airtight containers to keep them out.
Source: Wikipedia
Can I tell them apart from merchant grain beetles?
Yes, they have smaller eyes, a broader triangular head and cannot fly, unlike the merchant beetle.
Source: Wikipedia
Same family (Silvanidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Oryzaephilus_surinamensis
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.