''Oryzaephilus surinamensis'', the sawtoothed grain beetle, is a

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

in the superfamily ''

Cucujoidea Cucujoidea is a superfamily of beetles. This group formerly included all of the families now included in the superfamily Coccinelloidea. They include some fungus beetles and a diversity of lineages of "bark beetles" unrelated to the "true" bark be ...

''. It is a common, worldwide pest of grain and grain products as well as

chocolate Chocolate is a food made from roasted and ground cacao seed kernels that is available as a liquid, solid, or paste, either on its own or as a flavoring agent in other foods. Cacao has been consumed in some form since at least the Olmec civ ...

, drugs, and

tobacco Tobacco is the common name of several plants in the genus '' Nicotiana'' of the family Solanaceae, and the general term for any product prepared from the cured leaves of these plants. More than 70 species of tobacco are known, but the ...

. The species's binomial name, meaning "rice-lover from Suriname," was coined by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...

, who received specimens of the beetle from Surinam. It is also known as the malt beetle and may be referenced in the poem This Is The House That Jack Built in the line "....the rat that ate the malt that lay in the house that Jack built" the malt referenced may not be actual malted grain but a sawtoothed grain beetle.

Description and Identification

''O. surinamensis'' is a slender, dark brown

2.4–3 mm in size, with characteristic "teeth" running down the side of the

prothorax The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum ( dorsal), the prosternum ( ventral), and the propleuron ( lateral) o ...

. It is nearly identical to '' Oryzaephilus mercator'', or the Merchant Grain Beetle, however, ''O. surinamensis'' has smaller eyes and a broader, more triangular head; ''O. surinamensis'' unlike ''O. mercator'' are unable to fly.

Distribution

''O. surinamensis'' can be found worldwide. The beetle is one of the most commonly encountered stored product pests and is widespread within the food industry and can be found in

food manufacturing Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Food processing includes many forms of processing foods, from grinding grain to make raw flour to home cooking to complex ind ...

, storage, and retail facilities, as well as in home pantries. ''O. surinamensis'' is less common in colder climates such as Canada and the Northern United States

Life Cycle

Eggs

A female can produce 43-285

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

s in their six to ten month average lifespan which are deposited on a food mass. The ideal temperature range for larvae development within eggs is about 27-29° C (80-85° F), under such conditions they hatch in three to five days.

Larvae

Larvae are yellow-white with brown heads and grow up to 3mm. They crawl freely around the food mass and feed on broken pieces of grain or grain kernels damaged by other insects, larger larvae may bore into kernels. Larvae account for the majority of damage done to grain. Larvae molt two to four times before pupation

Pupae

Larvae

pupa A pupa ( la, pupa, "doll"; plural: ''pupae'') is the life stage of some insects undergoing transformation between immature and mature stages. Insects that go through a pupal stage are holometabolous: they go through four distinct stages in thei ...

te by constructing cocoon-like coverings using broken pieces of grain. Emergence as adults occurs after about one week

Adults

Adults can live on average six to ten months, though they can live as long as three years. The total life cycle is 27 – 51 days at . Adults seek out new sources of food for breeding. In areas which have severe infestations of ''O. surinamensis'' adults have been reported to nibble on the skin of people, however, these bites are not harmful.

Role as a Stored Product Pest and Control of Infestations

''O. surinamensis'' is one of the most commonly encountered insects in grain, pet foods, and seeds. Feeding results in shrinkage of the dry mass of the infested product and in increased water content due to the metabolic activity of the insects which can result in mold growth. In grain, insect damage decreases value and can make it unfit for use; sufficient numbers of insect fragments or live insects can result in rejection by the purchaser. In the home, infestations can be avoided by storing dried food products in sealed containers. To control already present infestations, the infested material needs to be identified and disposed of, or frozen- as all life stages of the beetle can be killed by being frozen for six days. In food processing operations and warehouses other means of control may be necessary and fumigation is commonly used, in large-scale grain storage operations a pesticide application may be needed for storage over six months. Fumigation is commonly used to control stored product pests in food and grain, this involves the treatment of product with gasses which are able to diffuse throughout the treated area. The gasses used in fumigation (most often phosphine) are highly toxic to both

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s and mammals (including

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...

s) but when applied properly, no fumigant will remain in product after treatment is complete. Because of the high toxicity of fumigants, their use is restricted to qualified applicators and areas which can be tightly sealed.

References

External links

{{Taxonbar, from=Q779905 Silvanidae Beetles of South America Beetles described in 1758 Storage pests Taxa named by Carl Linnaeus