''Sitophilus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

weevil Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and herbivorous. Approximately 97,000 species of weevils are known. They belong to several families, ...

s in the

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to confli ...

Litosomini The LitosominiLacordaire JT (1866) ''Histoire naturelle des insectes. Genera des coléoptères ou exposé méthodique et critique de tous les genres proposés jusqu’ici dans cet ordre d’insectes. Les familles des Curculionides (suite), Scolyt ...

. Some species are familiar as

pests PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...

of stored grain, nut, or seed. Notable pest species include the

rice weevil Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera ''Zizania'' and '' Porteresia'', both wild and domesticated, ...

(''S. oryzae''),

wheat weevil The wheat weevil (''Sitophilus granarius''), also known as the grain weevil or granary weevil, is an insect that feeds on cereal grains, and is a common pest in many places. It can cause significant damage to harvested stored grains and may drasti ...

(''S. granarius''), and

maize weevil Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The ...

(''S. zeamais''). Among the ''Stiophilus'' are species which destroy stored

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domesticat ...

, sorghum,Control of Sitophilus zeamais Mots., 1958 and Sitophilus oryzae (L., 1763) weevils (Coleoptera, Curculionidae) in stored rice grain (Oryza sativa l.) with insecticide pirimiphos methyl (Actellic 500 CE)
B. Alleoni1, W. Ferreira 9th International Working Conference on Stored Product Protection

oats The oat (''Avena sativa''), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other cereals and pseudocereals). While oats are suitable for human co ...

barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...

, rye,

buckwheat Buckwheat (''Fagopyrum esculentum''), or common buckwheat, is a flowering plant in the knotweed family Polygonaceae cultivated for its grain-like seeds and as a cover crop. The name "buckwheat" is used for several other species, such as ''Fagopy ...

peas The pea is most commonly the small spherical seed or the seed-pod of the flowering plant species ''Pisum sativum''. Each pod contains several peas, which can be green or yellow. Botanically, pea pods are fruit, since they contain seeds and d ...

cottonseed Cottonseed is the seed of the cotton plant. Composition The mature seeds are brown ovoids weighing about a tenth of a gram. By weight, they are 60% cotyledon, 32% coat and 8% embryonic root and shoot. These are 20% protein, 20% oil and 3.5% sta ...

, processed cereal products such as

pasta Pasta (, ; ) is a type of food typically made from an unleavened dough of wheat flour mixed with water or eggs, and formed into sheets or other shapes, then cooked by boiling or baking. Rice flour, or legumes such as beans or lentils, ar ...

cassava ''Manihot esculenta'', commonly called cassava (), manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America. Although a perennial plant, cassava is extensively cultivated ...

, and fruits such as

apples An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple trees are cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, where its wild ancestor, ' ...

Distribution

The rice and maize weevils have a nearly cosmopolitan distribution, occurring throughout the warmer parts of the world. In Europe they are replaced by the temperate Palearctic

Biology

The adult female weevil bores a hole in a grain, nut, or seed, and deposits an egg, usually one egg per individual grain. She seals the hole with a secretion. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. ...

develops while feeding on the interior of the grain, and then

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 ...

tes. It usually leaves the grain completely hollow when it exits as an adult.Plarre, R. (2010)
An attempt to reconstruct the natural and cultural history of the granary weevil, ''Sitophilus granarius'' (Coleoptera: Curculionidae).
''Eur J Entomol'' 107, 1-11. The wheat weevil can live on acorns, and may have used them as a host before agriculture made grain plentiful. The rice weevil can live on beans, nuts, grains, and some types of fruit, such as

grape A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus '' Vitis''. Grapes are a non- climacteric type of fruit, generally occurring in clusters. The cultivation of grapes began perhaps 8,000 years a ...

s. Several other ''Sitophilus'' use the acorns of

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

s such as

bluejack oak ''Quercus incana'' is a species of oak known by the common names bluejack oak, upland willow oak, sandjack oak, and cinnamon oak. It is native to the Atlantic coastal plain, Atlantic and Gulf coastal plains of the United States, from Virginia arou ...

(''Quercus incana'') and moru oak (''Q. floribunda''). Some use the seeds of trees in the Dipterocarpaceae and the legume family, Fabaceae. The tamarind weevil (''S. linearis'') is only known from the seeds of

tamarind Tamarind (''Tamarindus indica'') is a leguminous tree bearing edible fruit that is probably indigenous to tropical Africa. The genus ''Tamarindus'' is monotypic, meaning that it contains only this species. It belongs to the family Fabaceae ...

. Several ''Sitophilus'' species are hosts to an intracellular γ-Proteobacterium. Weevil and bacterium have a symbiotic relationship in which the bacterium produces nutrients such as amino acids and vitamins for the host, supplementing its cereal diet.Vallier, A., et al. (2009)
RNAi in the cereal weevil ''Sitophilus'' spp: systemic gene knockdown in the bacteriome tissue.
''BMC Biotechnology'' 9(1), 44.

Diversity

As of 1993, there are about 14 species of ''Sitophilus''. Species include: *'' Sitophilus conicollis'' *'' Sitophilus cribrosus'' *'' Sitophilus erosa'' *'' Sitophilus glandium'' *'' Sitophilus granarius'' – wheat weevil, granary weevil *'' Sitophilus linearis'' – tamarind weevil *'' Sitophilus oryzae'' – rice weevil *'' Sitophilus quadrinotatus'' *'' Sitophilus rugicollis'' *'' Sitophilus rugosus'' *'' Sitophilus sculpturatus'' *'' Sitophilus vateriae'' *'' Sitophilus zeamais'' – maize weevil

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

taxa include: *'' Sitophilus punctatissimus''

References

External links

* Obata, H., et al. (2011)
A new light on the evolution and propagation of prehistoric grain pests: The world's oldest maize weevils found in Jomon Potteries, Japan.
'' PLoS ONE'' 6(3) e14785. . {{Taxonbar, from=Q1431435 Dryophthorinae Insect pests of millets Storage pests