''Bruchus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 ...

s in the leaf beetle family,

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

. They are distributed mainly in the

Palearctic The Palearctic or Palaearctic is the largest of the eight biogeographic realms of the Earth. It stretches across all of Eurasia north of the foothills of the Himalayas, and North Africa. The realm consists of several bioregions: the Euro-Sibe ...

,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 large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

.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 there ...

. 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. 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 Taxonomic rank, superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and Herbivore, herbivorous. Approximately 97,000 species of weevils are known. They b ...

s, and because in most species, 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. The ...

e develop inside

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

s, particularly

bean A bean is the seed of several plants in the family Fabaceae, which are used as vegetables for human or animal food. They can be cooked in many different ways, including boiling, frying, and baking, and are used in many traditional dishes th ...

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 la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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, an arrangement of spines or plates on the tibia of the middle leg of the male, and the unique morphology of the male genitalia. 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, "with a characteristic boomerang 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 (singular seta ; from the Latin word for "bristle") are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Annelid setae are stiff bristles present on the body. Th ...

e. Some species have red or red-orange legs. The elytra are marked with straight lines.

Biology

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

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

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'' Mil ...

(Vicieae), which includes

pea 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 ...

s, sweet peas, lentils, 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 othe ...

. 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 likely native to North Africa, Western Asia and Europe, but is now naturalized in temperate and ...

(''Vicia sativa''), which is host to five recorded species, and

meadow vetchling ''Lathyrus pratensis'' or meadow vetchling, yellow pea, meadow pea and meadow pea-vine, is a perennial legume that grows to 1.2 m in height. The hermaphrodite flowers are pollinated by bees. As a perennial, this plant reproduces itself over man ...

(''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 that may have evolved in response to ''Bruchus'' and other seed-beetles. The fruit pods develop a callus when attacked, by the beetle, and this growth is mediated by bruchins, compounds so far known only from seed-beetles. These beetles are univoltine, 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 (''Lens culinaris'' or ''Lens esculenta'') is an edible legume. It is an annual plant known for its lens-shaped seeds. It is about tall, and the seeds grow in pods, usually with two seeds in each. As a food crop, the largest pro ...

s, ''B. pisorum'' on

s, and '' B. rufimanus'' on fava beans. ''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'') seeds in the ruins of Akrotiri, a settlement on the island of

Santorini Santorini ( el, Σαντορίνη, ), officially Thira (Greek: Θήρα ) and classical Greek Thera (English pronunciation ), is an island in the southern Aegean Sea, about 200 km (120 mi) southeast from the Greek mainland. It is the ...

destroyed in the

Minoan eruption The Minoan eruption was a catastrophic Types of volcanic eruptions, volcanic eruption that devastated the Aegean Islands, Aegean island of Thera (also called Santorini) circa 1600 BCE. It destroyed the Minoan civilization, Minoan settlement at ...

of its

volcano A volcano is a rupture 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 often found where tectonic plates are ...

.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 ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

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

Systematics

Linnaeus 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 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 have shown that the genus as it is now defined is

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

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

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

". 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 brachialis'', the vetch bruchid, is a species of leaf beetle in the family Chrysomelidae. It is found in Europe & Northern Asia (excluding China) and North America. References Further reading * * External links

* Bruc ...

'' *'' 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 pisorum'', known generally as pea weevil, is a species of leaf beetle in the family Chrysomelidae. Other common names include the pea beetle and pea seed beetle. It is found in Europe and Northern Asia (excluding China), North America, an ...

'' *'' Bruchus rufimanus'' *'' Bruchus rufipes'' *'' Bruchus sibiricus'' *'' Bruchus signaticornis'' *'' Bruchus tetragonus'' *'' Bruchus tristiculus'' *'' Bruchus tristis'' *'' Bruchus ulicis'' *'' Bruchus venustus'' *'' Bruchus viciae''