Bruchus

Bruchus
	Bruchus brachialis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Coleoptera
Infraorder:	Cucujiformia
Family:	Chrysomelidae
Subfamily:	Bruchinae
Tribe:	Bruchini
Genus:	Bruchus ; Linnaeus, 1767
Species
	see text

Last updated October 16, 2023

Bruchus is a genus of beetles in the leaf beetle family, Chrysomelidae. They are distributed mainly in the Palearctic,^[1] especially in Europe.^[2] Several occur in other parts of the world, such as North America, Africa, and Australia, as introduced species.^[1] Several species are notorious agricultural pests.

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 weevils, and because in most species, the larvae develop inside seeds, particularly beans.^[3]^[4] Because Bruchinae was known as the family Bruchidae until the 1990s,^[1] 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.^[1] The latter are slender and elongated,^[5] and the eighth abdominal sternite in particular is large and sclerotized, "with a characteristic boomerang shape".^[3] This part of the genitalia has been called the "urosternite", but other authors suggest the term "ventral plate" is more appropriate.^[3] The robust ventral plate of Bruchus helps distinguish the genus from other seed-beetles, which tend to have vestigial or lobe-like ventral plates.^[3] 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.^[3]

In general, these beetles have black bodies with patterns of white or yellow setae. Some species have red or red-orange legs. The elytra are marked with straight lines.^[5]

Biology

Bruchus are specialists, feeding and developing almost exclusively on plants of the legume tribe Fabeae (Vicieae),^[1] which includes peas, sweet peas, lentils, and vetches. Examples include cow vetch (Vicia cracca), which is attacked by at least nine Bruchus species, common vetch (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.^[1] Some Bruchus species are monophagous, living on just one host plant species.^[2]

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.^[1]

These beetles are univoltine, producing one generation per year.^[1] 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 through fall and winter, waiting until spring to reproduce.^[1]

Impacts

Among the major agricultural pests in the genus are B. lentis on lentils, B. pisorum on peas, and B. rufimanus on fava beans.^[1]Bruchus species are among the worst pests of lentils, in one study causing a 30% loss of a crop.^[6] 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.^[4]

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 destroyed in the Minoan eruption of its volcano.^[7] The inhabitants used the vetchling seeds for food.^[8] Charred remains of B. rufipes, a pest of the plant, were recovered from the jars and the chitin was successfully radiocarbon dated, providing evidence that the date of the eruption was between 1744 and 1538 BC.^[7]

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.^[9]

Phylogenetic analyses have shown that the genus as it is now defined is monophyletic,^[2] but also that two of the seven groups in the genus are "potentially paraphyletic".^[3]

As of 2008, about 36^[1]^[3] species are in the genus.

Species include:^[1]^[3]

Related Research Articles

Lathyrus is a genus of flowering plants in the legume family Fabaceae, and contains approximately 160 species. Commonly known as peavines or vetchlings, they are native to temperate areas, with a breakdown of 52 species in Europe, 30 species in North America, 78 in Asia, 24 in tropical East Africa, and 24 in temperate South America. There are annual and perennial species which may be climbing or bushy. This genus has numerous sections, including Orobus, which was once a separate genus. The genus has numerous synonyms, including Pisum, the ancient Latin name for the pea.

The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle families. Numerous subfamilies are recognized, but the precise taxonomy and systematics are likely to change with ongoing research.

The bean weevils or seed beetles are a subfamily (Bruchinae) of beetles, now placed in the family Chrysomelidae, though they have historically been treated as a separate family. They are granivores, and typically infest various kinds of seeds or beans, living most of their lives inside a single seed. The subfamily includes about 1,650 species and are found worldwide.

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 genera of their subfamily Faboideae also have names containing "vetch", for example the vetchlings (Lathyrus) or the milk-vetches (Astragalus). The lentils are included in genus Vicia, and were formerly classified in genus Lens. The broad bean is sometimes separated in a monotypic genus Faba; although not often used today, it is of historical importance in plant taxonomy as the namesake of the order Fabales, the Fabaceae and the Faboideae. The tribe Vicieae in which the vetches are placed is named after the genus' current name. The true peas (Pisum) are among the closest living relatives of vetches.

Callosobruchus maculatus is a species of beetles known commonly as the cowpea weevil or cowpea seed beetle. It is a member of the leaf beetle family, Chrysomelidae, and not a true weevil. This common pest of stored legumes has a cosmopolitan distribution, occurring on every continent except Antarctica. The beetle most likely originated in West Africa and moved around the globe with the trade of legumes and other crops. As only a small number of individuals were likely present in legumes carried by people to distant places, the populations that have invaded various parts of the globe have likely gone through multiple bottlenecks. Despite these bottlenecks and the subsequent rounds of inbreeding, these populations persist. This ability to withstand a high degree of inbreeding has likely contributed to this species’ prevalence as a pest.

Caryobruchus gleditsiae is a species of beetle in the family Chrysomelidae. It lives in North and Central America and develops inside the seeds of palm trees. Adults grow to a maximum length of 11 mm (0.43 in), the size depending on the size of the seed it grew up in. The species was first described by Carl Linnaeus in his 1763 Centuria Insectorum.

Spermophagus is a genus of beetles belonging to the family Chrysomelidae subfamily Bruchinae.

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 Santorini in Greece and was recently added to the European Union's products with a Protected Designation of Origin.

Acanthoscelides is a genus of bean weevils of the subfamily Bruchinae. They are native to the New World. About one third of them can be found in Mexico.

Bruchidius is a genus of beetles in the bean weevil subfamily (Bruchinae) of the leaf beetle family, Chrysomelidae. Most are native to the Old World.

Callosobruchus chinensis is a common species of beetle found in the bean weevil subfamily, and is known to be a pest to many stored legumes. Although it is commonly known as the adzuki bean weevil it is in fact not a true weevil, belonging instead to the leaf beetle family, Chrysomelidae. Other common names include the pulse beetle, Chinese bruchid and cowpea bruchid. This species has a very similar lifestyle and habitat to Callosobruchus maculatus and their identities are often mistaken for each other. This beetle is a common pest targeting many different species of stored legumes and it is distributed across the tropical and subtropical regions of the world. C. chinensis is one of the most damaging crop pests to the stored legume industry due to their generalized legume diets and wide distribution.

Acanthoscelides obtectus, the bean weevil, is a species of bruchid beetle. The species was described in 1831 by Thomas Say.

Callosobruchus is a genus of beetles in the family Chrysomelidae, the leaf beetles. It is in the subfamily Bruchinae, the bean weevils. Many beetles in the genus are well known as economically important pests that infest stored foodstuffs.

Bruchidius siliquastri is a species of bean weevil. It was first found in pods of Cercis siliquastrum in China, and has thence been found in several continents. Its length ranges from 2.8 to 3.7 millimetres. Its body is short and ovate, with a black integument. The apex of its femora and the ventral part of its hind tarsi are reddish. Its vestiture is made of thin and short setae; dorsally setae are a whitish colour, denser on the scutellum. Its pygidium is also covered with setae. Its name is derived from its host plant.

Bruchus brachialis, the vetch bruchid, is a species of leaf beetle in the family Chrysomelidae. It is found in Europe & Northern Asia and North America.

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, North America, and temperate Asia.

Caryedon is a genus of pea and bean weevils in the beetle family Chrysomelidae. There are about 11 described species in Caryedon.

Bruchidius brincki, is a species of leaf beetle found in Sri Lanka and Vietnam.

Bruchidius mendosus, is a species of leaf beetle found in India, Sri Lanka, Bhutan, Iran, Myanmar, Nepal, Thailand, Vietnam, and Yemen.

Bruchidius nalandus, is a species of leaf beetle found in Congo, India, Indonesia, Iran, Kenya, South Africa, Sri Lanka, United Arab Emirates, Vietnam and Socotra Island.

References

1 2 3 4 5 6 7 8 9 10 11 12 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.
1 2 3 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.
1 2 3 4 5 6 7 8 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.
1 2 Tuda, M. (2007). Applied evolutionary ecology of insects of the subfamily Bruchinae (Coleoptera: Chrysomelidae). Applied Entomology and Zoology 42(3), 337-46.
1 2 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.
↑ 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.
1 2 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.
↑ Melamed, Y., et al. (2009). Lathyrus clymenum L. in Israel: A "revival" of an ancient species. Archived October 7, 2013, at the Wayback Machine Israel Journal of Plant Sciences 57(1-2), 125-30.
↑ 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.
1 2 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.