''Sitophilus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 fa ...

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 use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

Litosomini. 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 The rice weevil (''Sitophilus oryzae'') is a stored product Pest (organism), pest which attacks seeds of several crops, including wheat, rice, and maize. Description The adults are usually between long, with a long snout. The body color appears ...

(''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 drast ...

(''S. granarius''), and

maize weevil The maize weevil (''Sitophilus zeamais''), known in the United States as the greater rice weevil, is a species of beetle in the family Curculionidae. It can be found in numerous tropical areas around the world, and in the United States, and is a m ...

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

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...

sorghum ''Sorghum bicolor'', commonly called sorghum () and also known as great millet, broomcorn, guinea corn, durra, imphee, jowar, or milo, is a species in the Poaceae, grass genus ''Sorghum (genus), Sorghum'' cultivated for its grain. The grain i ...

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). Oats appear to have been domesticated as a secondary crop, as their seed ...

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

rye Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is grown principally in an area from Eastern and Northern Europe into Russia. It is much more tolerant of cold weather and poor soil than o ...

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. Buckwheat originated around the 6th millennium BCE in the region of what ...

peas Pea (''pisum'' in Latin) is a pulse or fodder crop, but the word often refers to the seed or sometimes the pod of this flowering plant species. Peas are eaten as a vegetable. Carl Linnaeus gave the species the scientific name ''Pisum sativum ...

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 A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...

products such as

pasta Pasta (, ; ) is a type of food typically made from an Leavening agent, unleavened dough of wheat flour mixed with water or Eggs as food, eggs, and formed into sheets or other shapes, then cooked by boiling or baking. Pasta was originally on ...

cassava ''Manihot esculenta'', common name, commonly called cassava, manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America, from Brazil, Paraguay and parts of the Andes. Although ...

, and fruits such as

apples An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

Distribution

The rice and maize weevils have a nearly

cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

, occurring throughout the warmer parts of the world. In Europe they are replaced by the temperate

Palearctic The Palearctic or Palaearctic is a biogeographic realm of the Earth, the largest of eight. Confined almost entirely to the Eastern Hemisphere, it stretches across Europe and Asia, north of the foothills of the Himalayas, and North Africa. Th ...

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 (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

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

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 ...

tes. It usually leaves the grain completely hollow when it exits as an adult. The wheat weevil can live on

acorn The acorn is the nut (fruit), nut of the oaks and their close relatives (genera ''Quercus'', ''Notholithocarpus'' and ''Lithocarpus'', in the family Fagaceae). It usually contains a seedling surrounded by two cotyledons (seedling leaves), en ...

s, 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 approximately 8,0 ...

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

oak An oak is a hardwood tree or shrub in the genus ''Quercus'' of the beech family. They have spirally arranged leaves, often with lobed edges, and a nut called an acorn, borne within a cup. The genus is widely distributed in the Northern Hemisp ...

s such as bluejack oak (''Quercus incana'') and moru oak (''Q. floribunda''). Some use the seeds of trees in the

Dipterocarpaceae Dipterocarpaceae is a family (biology), family of flowering plants with 22 genera and about 695 known species of mainly lowland tropical forest trees. Their distribution is pantropical, from northern South America to Africa, the Seychelles, India ...

and the

legume Legumes are plants in the pea family Fabaceae (or Leguminosae), or the fruit or seeds of such plants. When used as a dry grain for human consumption, the seeds are also called pulses. Legumes are grown agriculturally, primarily for human consum ...

family,

Fabaceae Fabaceae () or Leguminosae,International Code of Nomen ...

. The tamarind weevil (''S. linearis'') is only known from the seeds of

tamarind Tamarind (''Tamarindus indica'') is a Legume, leguminous tree bearing edible fruit that is indigenous to tropical Africa and naturalized in Asia. The genus ''Tamarindus'' is monotypic taxon, monotypic, meaning that it contains only this spe ...

. Several ''Sitophilus'' species are hosts to an intracellular γ-Proteobacterium. Weevil and bacterium have a

symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

relationship in which the bacterium produces nutrients such as amino acids and vitamins for the host, supplementing its cereal diet.

Diversity

As of 1993, there are about 14 species of ''Sitophilus''. Species include: *'' Sitophilus conicollis'' *'' Sitophilus cribrosus'' *'' Sitophilus erosa'' *'' Sitophilus glandium'' *''

Sitophilus granarius 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 drast ...

'' – wheat weevil, granary weevil *'' Sitophilus linearis'' – tamarind weevil *''

Sitophilus oryzae The rice weevil (''Sitophilus oryzae'') is a stored product pest which attacks seeds of several crops, including wheat, rice, and maize. Description The adults are usually between long, with a long snout. The body color appears to be brown/bla ...

'' – 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 preserve ...

taxa include: *''

Sitophilus punctatissimus ''Sitophilus'' is a genus of weevils in the Tribe (biology), tribe Litosomini. Some species are familiar as pest (organism), pests of stored grain, nut, or seed. Notable pest species include the rice weevil (''S. oryzae''), wheat weevil (''S. gra ...

References

External links

* {{Authority control Dryophthorinae Insect pests of millets Storage pests Taxa named by Carl Johan Schönherr Curculionidae genera