Merchant Grain Beetle (or closely related Sawtoothed Grain Beetle)
Scientific Name: Oryzaephilus mercator (or Oryzaephilus surinamensis)
Order & Family: Order: Coleoptera (Beetles), Family: Silvanidae (Flat Grain Beetles)
Size: Very small, typically 2.5 mm to 3 mm in length.
Natural Habitat
Often found indoors in pantries, kitchens, and food storage areas, particularly in grain products like cereal, flour, oatmeal, cookies, pasta, and dried fruits.
Diet & Feeding
They feed on processed cereals, oats, flour, cake mix, pasta, chocolate, and dried fruits. They are unable to feed on whole grains unless the kernels are already broken.
Behavior Patterns
These beetles are strong runners but some species (Sawtoothed) do not fly, while the Merchant Grain Beetle can fly. They are flattened insects, allowing them to crawl into tightly sealed cardboard packages. They tend to congregate in food packaging, leading to infestations.
Risks & Benefits
Risks: They are a common stored product pest that ruins food by contamination. While they do not bite, sting, or carry diseases dangerous to humans, their presence renders food unfit for consumption. Benefits: None in a household setting; ecologically, they help decompose plant matter.
Identified on: 2/7/2026