Merchant Grain Beetle

Oryzaephilus mercator

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Superfamily: Cucujoidea
Family: Silvanidae
Subfamily: Silvaninae
Genus: Oryzaephilus
Species: mercator

Pronunciation

How to pronounce Oryzaephilus mercator: /ɔːˌraɪzəˈfɪləs mɜrˈkeɪtɔr/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Silvanus mercator Jacobson by Georgiy Jacobson. Used under a Public domain license.

Oryzaephilus.mercator by Sarefo. Used under a CC BY-SA 3.0 license.

Oryzaephilus mercator larva by Caroline Harding, MAF. Used under a CC BY 3.0 au license.

Oryzaephilus mercator by Caroline Harding, MAF. Used under a CC BY 3.0 au license.

Oryzaephilus mercator (Fauvel, 1889) (14239527277) by Udo Schmidt from Deutschland. Used under a CC BY-SA 2.0 license.

Oryzaephilus mercator 161694781 by Nicolas Bédard. Used under a CC0 license.

Summary

Oryzaephilus mercator, known as the merchant grain beetle, is a widely distributed pest of grain and grain products, as well as other foodstuffs like fruit and chocolate. It can be distinguished from its close relative, O. surinamensis, by specific morphological traits and is recognized for its impact on stored grain.

Physical Characteristics

A small, flattened beetle about 2.5mm in length; characterized by narrow area just behind the eyes compared to O. surinamensis, which has a broader, more triangular head and larger eyes. Adults are capable of flight.

Identification Tips

Distinguished from O. surinamensis by the shape of the head and the projection behind the eye, which is narrow and protruding in O. mercator.

Habitat

Commonly found in cosmopolitan regions; in Canada, it is more frequently found in apartments and multiple dwellings than in houses.

Distribution

Adventive in North America; of tropical origin.

Diet

Adults and larvae primarily feed on cereal products, particularly oatmeal, bran, shelled sunflower seeds, rolled oats, and brown rice. Also associated with seed-borne fungi.

Life Cycle

Females produce 500 to 1000 eggs in a year, deposited within a food source. Larvae are yellowish-white with a brown head and can reach about 3mm in length. The total life cycle takes approximately 27–50 days.

Reproduction

Females deposit eggs within food sources. Larvae move about as they feed and molt two to four times before pupating.

Ecosystem Role

A common household pest that contributes to the destruction of stored grain and potential mold growth due to increased grain moisture.

Economic Impact

One of the most commonly encountered pests in grain and grain products, causing crop shrinkage and quality degradation.

Similar Taxa

Oryzaephilus surinamensis