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

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

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 ...

. It is a common, worldwide pest of

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached husk, hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and ...

and grain products as well as

chocolate Chocolate is a food made from roasted and ground cocoa beans that can be a liquid, solid, or paste, either by itself or to flavoring, flavor other foods. Cocoa beans are the processed seeds of the cacao tree (''Theobroma cacao''); unprocesse ...

drug A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug i ...

s, 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' binomial name, meaning "rice-lover from

Suriname Suriname, officially the Republic of Suriname, is a country in northern South America, also considered as part of the Caribbean and the West Indies. It is a developing country with a Human Development Index, high level of human development; i ...

," was coined by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

, 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 "This Is the House That Jack Built" is a popular English nursery rhyme and cumulative tale. It has a Roud Folk Song Index number of 20854. It is Aarne–Thompson–Uther Index type 2035. Lyrics This is perhaps the most common set of modern lyr ...

in the line "....the rat that ate the malt that lay in the house that Jack built" the

malt Malt is any cereal grain that has been made to germinate by soaking in water and then stopped from germinating further by drying with hot air, a process known as "malting". Malted grain is used to make beer, whisky, malted milk, malt vinegar, ...

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) on ...

. It is nearly identical to '' Oryzaephilus mercator'', or the Merchant Grain Beetle, however, ''O. surinamensis'' has smaller

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

s and a broader, more triangular head; ''O. surinamensis'' unlike ''O. mercator'' are unable to

fly Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advanced ...

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 takes many forms, from grinding grain into raw flour, home cooking, and complex industrial methods used in the mak ...

, 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, though is still cold hardy enough to be one of the most common grain feeding insects in Canadian farms.

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 ...

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 A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect developmental biology, development such as insects, some arachnids, amphibians, or cnidarians typical ...

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 (; : 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 their life cycle, the stages th ...

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

''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.

Control of infestations

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 Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

application may be needed for storage over six months.

Fumigation Fumigation is a method of pest control or the removal of harmful microorganisms by completely filling an area with gaseous pesticides, or fumigants, to suffocate or poison the pests within. It is used to control pests in buildings (structural ...

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 Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

s and

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s (including

human Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...

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