''Bruchus'' 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 ...

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 ...

s in the leaf beetle family,

Chrysomelidae The beetle family Chrysomelidae, commonly known as leaf beetles, includes over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making it one of the largest and most commonly encountered of all beetle families. Numerous s ...

. They are distributed mainly in the

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 ...

,Kergoat, G. J., et al. (2007)
Defining the limits of taxonomic conservatism in host–plant use for phytophagous insects: Molecular systematics and evolution of host–plant associations in the seed-beetle genus ''Bruchus'' Linnaeus (Coleoptera: Chrysomelidae: Bruchinae).
''Molecular Phylogenetics and Evolution'' 43(1), 251-69. especially in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

.Kergoat, G. J., et al. (2004)
Phylogeny and host-specificity of European seed beetles (Coleoptera, Bruchidae), new insights from molecular and ecological data.
''Molecular Phylogenetics and Evolution'' 32(3), 855-65. Several occur in other parts of the world, such as North America, Africa, and Australia, as

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

. Several species are notorious agricultural

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 ...

. The genus is part of the subfamily

Bruchinae The bean weevils or seed beetles are a subfamily (Bruchinae) of weevils, which in turn are a subset of beetles. The Bruchinae now placed in the family Chrysomelidae, though they have historically been treated as a separate family. The subfamily ...

. Members of the subfamily are known commonly as bean weevils. Many authors prefer to call them seed-beetles or bean beetles, because they are not true

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, and because in most species, 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 ...

e develop inside

seed In botany, a seed is a plant structure containing an embryo and stored nutrients in a protective coat called a ''testa''. More generally, the term "seed" means anything that can be Sowing, sown, which may include seed and husk or tuber. Seeds ...

s, particularly

bean A bean is the seed of some plants in the legume family (Fabaceae) used as a vegetable for human consumption or animal feed. The seeds are often preserved through drying (a ''pulse''), but fresh beans are also sold. Dried beans are traditi ...

s.Kergoat, G. J. and N. Alvarez. (2008)
Assessing the phylogenetic usefulness of a previously neglected morphological structure through elliptic Fourier analyses: a case study in ''Bruchus'' seed-beetles (Coleoptera: Chrysomelidae: Bruchinae).
''Systematic Entomology'' 33(2), 289-300.Tuda, M. (2007)
Applied evolutionary ecology of insects of the subfamily Bruchinae (Coleoptera: Chrysomelidae).
''Applied Entomology and Zoology'' 42(3), 337-46. Because Bruchinae was known as the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Bruchidae until the 1990s, they are sometimes still called bruchid beetles.

Description

The genus ''Bruchus'' is well-defined by a number of characters, such as the shape of the

pronotum 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 e ...

, an arrangement of spines or plates on the tibia of the middle

leg A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element cap ...

of the male, and the unique morphology of the male

genitalia A sex organ, also known as a reproductive organ, is a part of an organism that is involved in sexual reproduction. Sex organs constitute the primary sex characteristics of an organism. Sex organs are responsible for producing and transporting ...

. The latter are slender and elongated,Kingsolver, J. M
''Handbook of the Bruchidae of the United States and Canada (Insecta, Coleoptera)'', Volume I.
Technical Bulletin 1912. USDA ARS. 2004. pg. 69. and the eighth abdominal sternite in particular is large and

sclerotized Sclerosis (also sclerosus in the Latin names of a few disorders) is a hardening of tissue and other anatomical features. It may refer to: * Sclerosis (medicine), a hardening of tissue * in zoology, a process which forms sclerites, a hardened exo ...

, "with a characteristic

boomerang A boomerang () is a thrown tool typically constructed with airfoil sections and designed to spin about an axis perpendicular to the direction of its flight, designed to return to the thrower. The origin of the word is from Australian Aborigin ...

shape". This part of the genitalia has been called the "urosternite", but other authors suggest the term "ventral plate" is more appropriate. The robust ventral plate of ''Bruchus'' helps distinguish the genus from other seed-beetles, which tend to have

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

or lobe-like ventral plates. The ventral plate is useful in identification because each species seems to have a distinctive shape to it, and it does not vary among individuals of one species. In general, these beetles have black bodies with patterns of white or yellow

seta In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...

e. Some species have red or red-orange legs. The

elytra An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...

are marked with straight lines.

Biology

''Bruchus'' are specialists, feeding and developing almost exclusively on plants of 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 ...

tribe

Fabeae The tribe Fabeae (sometimes referred to as "Vicieae") is one of the subdivisions of the plant family Fabaceae. It is included within the Inverted repeat-lacking clade (IRLC). Five genera are included: * ''Lathyrus'' L. (vetchlings) * ''Lens'' Mi ...

(Vicieae), which includes

pea 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' ...

s, sweet peas,

lentils The lentil (''Vicia lens'' or ''Lens culinaris'') is an annual plant, annual legume grown for its Lens (geometry), lens-shaped edible seeds or ''pulses'', also called ''lentils''. It is about tall, and the seeds grow in Legume, pods, usually w ...

, and

vetches ''Vicia'' is a genus of over 240 species of flowering plants that are part of the legume family (Fabaceae), and which are commonly known as vetches. Member species are native to Europe, North America, South America, Asia and Africa. Some other g ...

. Examples include cow vetch (''Vicia cracca''), which is attacked by at least nine ''Bruchus'' species,

common vetch ''Vicia sativa'', known as the common vetch, garden vetch, tare or simply vetch, is a nitrogen-fixing leguminous plant in the family Fabaceae. It is now naturalised throughout the world occurring on every continent, except Antarctica and the Arc ...

(''Vicia sativa''), which is host to five recorded species, and meadow vetchling (''Lathyrus pratensis'') and tuberous pea (''Lathyrus tuberosus''), which are each attacked by four species. Some ''Bruchus'' species are monophagous, living on just one host plant species. Some species of ''Lathyrus'' have an

antipredator adaptation Anti-predator adaptations are mechanisms developed through evolution that assist Predation, prey organisms in their constant struggle against predators. Throughout the animal kingdom, adaptations have evolved for every stage of this struggle, na ...

that may have evolved in response to ''Bruchus'' and other seed-beetles. The fruit pods develop a

callus A callus (: calluses) is an area of thickened and sometimes hardened skin that forms as a response to repeated friction, pressure, or other irritation. Since repeated contact is required, calluses are most often found on the feet and hands, b ...

when attacked, by the beetle, and this growth is mediated by bruchins, compounds so far known only from seed-beetles. These beetles are

univoltine Voltinism is a term used in biology to indicate the number of broods or generations of an organism in a year. The term is most often applied to insects, and is particularly in use in sericulture, where silkworm varieties vary in their voltinism. ...

, producing one generation per year. The female lays eggs on the fruit pod of its host legume in spring and summer, and the larva enters a seed to develop. The adult emerges, but remains in

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

through fall and winter, waiting until spring to reproduce.

Impacts

Among the major agricultural pests in the genus are ''B. lentis'' on

lentil The lentil (''Vicia lens'' or ''Lens culinaris'') is an annual plant, annual legume grown for its Lens (geometry), lens-shaped edible seeds or ''pulses'', also called ''lentils''. It is about tall, and the seeds grow in Legume, pods, usually w ...

s, ''B. pisorum'' on

s, and '' B. rufimanus'' on

fava beans ''Vicia faba'', commonly known as the broad bean, fava bean, or faba bean, is a species of vetch, a flowering plant in the pea and bean family Fabaceae. It is widely cultivated as a crop for human consumption, and also as a cover crop. Vari ...

. ''Bruchus'' species are among the worst pests of lentils, in one study causing a 30% loss of a crop.Laserna-Ruiz, I., et al. (2012)
Screening and selection of lentil (''Lens'' Miller) germplasm resistant to seed bruchids (''Bruchus'' spp.).
''Euphytica'' 188(2), 153-62. While many seed-beetles are pests of stored bean supplies, ''Bruchus'' species do not reproduce in postharvest dry bean stores, just in beans on the plant in the field. One species has proved more useful. ''B. rufipes'' was found inside jars of

Spanish vetchling ''Lathyrus clymenum'', also called Spanish vetchling, is a flowering plant in the family Fabaceae, native to the Mediterranean. The seeds are used to prepare a Greek dish called fava santorinis. The plant is cultivated on the island of Santorin ...

(''Lathyrus clymenum'') seeds in the ruins of Akrotiri, a settlement on the island of

Santorini Santorini (, ), officially Thira (, ) or Thera, is a Greek island in the southern Aegean Sea, about southeast from the mainland. It is the largest island of a small, circular archipelago formed by the Santorini caldera. It is the southern ...

destroyed in the

Minoan eruption The Minoan eruption was a catastrophic volcanic eruption that devastated the Aegean island of Thera (also called Santorini) circa 1600 BCE. It destroyed the Minoan settlement at Akrotiri, as well as communities and agricultural areas on near ...

of its

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

.Panagiotakopulu, E., et al. (2013)
Ancient pests: the season of the Santorini Minoan volcanic eruption and a date from insect chitin.
''Naturwissenschaften'' 100 683-89. The inhabitants used the vetchling seeds for food.Melamed, Y., et al. (2009)
''Lathyrus clymenum'' L. in Israel: A "revival" of an ancient species.
''Israel Journal of Plant Sciences'' 57(1-2), 125-30. Charred remains of ''B. rufipes'', a pest of the plant, were recovered from the jars and the

chitin Chitin (carbon, C8hydrogen, H13oxygen, O5nitrogen, N)n ( ) is a long-chain polymer of N-Acetylglucosamine, ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is the second most abundant polysaccharide in nature (behind only cell ...

was successfully

radiocarbon dated Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was de ...

, providing evidence that the date of the eruption was between 1744 and 1538 BC.

Systematics

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 ...

erected the genus, and initially it contained almost all the known species of seed-beetles. The genus was divided over time and many species were distributed into new genera. Some authors, though, continued to classify new seed-beetles in ''Bruchus'', creating a disorganized taxon full of species quite obviously unrelated to one another. Today, after revisions, the

circumscription Circumscription may refer to: * Circumscribed circle * Circumscription (logic) *Circumscription (taxonomy) * Circumscription theory, a theory about the origins of the political state in the history of human evolution proposed by the American anthr ...

of ''Bruchus'' is relatively clear.Kergoat, G. J., et al. (2011)
Phylogenetics, species boundaries and timing of resource tracking in a highly specialized group of seed beetles (Coleoptera: Chrysomelidae: Bruchinae).
''Molecular Phylogenetics and Evolution'' 59, 746-60.

Phylogenetic analyses In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as Computational phylogenetics, phylogenetic inference. It infers the relationship among organ ...

have shown that the genus as it is now defined is

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

, but also that two of the seven groups in the genus are "potentially

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

". As of 2008, about 36 species are in the genus. Species include: Bruchus atomarius1

*'' Bruchus affinis'' *'' Bruchus altaicus'' *'' Bruchus anatolicus''Anton, K.-W. (1999)
Two new species of the ''Bruchus brachialis'' group from the Mediterranean region (Coleoptera: Bruchidae: Bruchinae).
''Linzer Biologische Beiträge'' 31(2), 655-60. *'' Bruchus atomarius'' *''

Bruchus brachialis ''Bruchus'' is a genus of beetles in the leaf beetle family, Chrysomelidae. They are distributed mainly in the Palearctic,Kergoat, G. J., et al. (2007)Defining the limits of taxonomic conservatism in host–plant use for phytophagous insects: Mol ...

'' *'' Bruchus brisouti'' *'' Bruchus canariensis'' *'' Bruchus dentipes'' *'' Bruchus emarginatus'' *'' Bruchus ervi'' *'' Bruchus griseomaculatus'' *'' Bruchus hamatus'' *'' Bruchus hierroensis'' *'' Bruchus ibericus'' *'' Bruchus laticollis'' *'' Bruchus lends'' *'' Bruchus libanensis'' *'' Bruchus loti'' *'' Bruchus lugubris'' *'' Bruchus luteicornis'' *'' Bruchus mirabilicollis'' *'' Bruchus mulkaki'' *'' Bruchus occidentalis'' *'' Bruchus pavlovskii'' *'' Bruchus perezi'' *'' Bruchus pisorum'' *'' Bruchus rufimanus'' *'' Bruchus rufipes'' *'' Bruchus sibiricus'' *'' Bruchus signaticornis'' *'' Bruchus tetragonus'' *'' Bruchus tristiculus'' *'' Bruchus tristis'' *'' Bruchus ulicis'' *'' Bruchus venustus'' *'' Bruchus viciae''

Description

Biology

Impacts

Systematics

References

Further reading