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These styles generally have either two f-shaped soundholes like a violin (F-5 and A-5), or an oval sound hole (F-4 and A-4 and lower models) directly under the strings. Much variation exists between makers working from these archetypes, and other variants have become increasingly common. Generally, in the United States, Gibson F-hole F-5 mandolins and mandolins influenced by that design are strongly associated with bluegrass, while the A-style is associated other types of music, although it too is most often used for and associated with bluegrass. The F-5's more complicated woodwork also translates into a more expensive instrument. |
Numerous modern mandolin makers build instruments that largely replicate the Gibson F-5 Artist models built in the early 1920s under the supervision of Gibson acoustician Lloyd Loar. Original Loar-signed instruments are sought after and extremely valuable. Other makers from the Loar period and earlier include Lyon and Healy, Vega and Larson Brothers. Some notable modern American carved mandolin manufacturers include, in addition to Kay, Gibson, Weber, Monteleone and Collings. Mandolins from other countries include The Loar (China), Santa, Rosa (China), Michael Kelly (Korea), Eastman (China), Kentucky (China), Heiden (Canada), Gilchrist (Australia) and Morgan Monroe (China). |
The international repertoire of music for mandolin is almost unlimited, and musicians use it to play various types of music. This is especially true of violin music, since the mandolin has the same tuning of the violin. Following its invention and early development in Italy the mandolin spread throughout the European continent. The instrument was primarily used in a classical tradition with Mandolin orchestras, so called Estudiantinas or in Germany Zupforchestern appearing in many cities. Following this continental popularity of the mandolin family local traditions appeared outside of Europe in the Americas and in Japan. Travelling mandolin virtuosi like Giuseppe Pettine, Raffaele Calace and Silvio Ranieri contributed to the mandolin becoming a "fad" instrument in the early 20th century. This "mandolin craze" was fading by the 1930s, but just as this practice was falling into disuse, the mandolin found a new niche in American country, old-time music, bluegrass and folk music. More recently, the Baroque and Classical mandolin repertory and styles have benefited from the raised awareness of and interest in Early music, with media attention to classical players such as Israeli Avi Avital, Italian Carlo Aonzo and American Joseph Brent. |
Phil Skinner played a key role in 20th century development of the mandolin movement in Australia, and was awarded an MBE in 1979 for services to music and the community. He was born Harry Skinner in Sydney in 1903 and started learning music at age 10 when his uncle tutored him on the banjo. Skinner began teaching part-time at age 18, until the Great Depression forced him to begin teaching full-time and learn a broader range of instruments. Skinner founded the Sydney Mandolin Orchestra, the oldest surviving mandolin orchestra in Australia. |
The Sydney Mandolins (Artistic Director: Adrian Hooper) have contributed greatly to the repertoire through commissioning over 200 works by Australian and International composers. Most of these works have been released on Compact Disks and can regularly be heard on radio stations on the ABC and MBS networks. One of their members, mandolin virtuoso Paul Hooper, has had a number of Concertos written for him by composers such as Eric Gross. He has performed and recorded these works with the Sydney Symphony Orchestra and the Tasmanian Symphony Orchestra. As well, Paul Hooper has had many solo works dedicated to him by Australian composers e.g., Caroline Szeto, Ian Shanahan, Larry Sitsky and Michael Smetanin. |
In the early 20th century several mandolin orchestras (Estudiantinas) were active in Belgium. Today only a few groups remain: Royal Estudiantina la Napolitaine (founded in 1904) in Antwerp, Brasschaats mandoline orkest in Brasschaat and an orchestra in Mons (Bergen). Gerda Abts is a well known mandolin virtuoso in Belgium. She is also mandolin teacher and gives lessons in the music academies of Lier, Wijnegem and Brasschaat. She is now also professor mandolin at the music high school “Koninklijk Conservatorium Artesis Hogeschool Antwerpen”. She also gives various concerts each year in different ensembles. She is in close contact to the Brasschaat mandolin Orchestra. Her site is www.gevoeligesnaar.be |
Prior to the Golden Age of Mandolins, France had a history with the mandolin, with mandolinists playing in Paris until the Napoleonic Wars. The players, teachers and composers included Giovanni Fouchetti, Eduardo Mezzacapo, Gabriele Leon, and Gervasio. During the Golden age itself (1880s-1920s), the mandolin had a strong presence in France. Prominent mandolin players or composers included Jules Cottin and his sister Madeleine Cottin, Jean Pietrapertosa, and Edgar Bara. Paris had dozens of "estudiantina" mandolin orchestras in the early 1900s. Mandolin magazines included L'Estudiantina, Le Plectre, École de la mandolie. |
On the island of Crete, along with the lyra and the laouto (lute), the mandolin is one of the main instruments used in Cretan Music. It appeared on Crete around the time of the Venetian rule of the island. Different variants of the mandolin, such as the "mantola," were used to accompany the lyra, the violin, and the laouto. Stelios Foustalierakis reported that the mandolin and the mpoulgari were used to accompany the lyra in the beginning of the 20th century in the city of Rethimno. There are also reports that the mandolin was mostly a woman's musical instrument. Nowadays it is played mainly as a solo instrument in personal and family events on the Ionian islands and Crete. |
Many adaptations of the instrument have been done to cater to the special needs of Indian Carnatic music. In Indian classical music and Indian light music, the mandolin, which bears little resemblance to the European mandolin, is usually tuned E-B-E-B. As there is no concept of absolute pitch in Indian classical music, any convenient tuning maintaining these relative pitch intervals between the strings can be used. Another prevalent tuning with these intervals is C-G-C-G, which corresponds to Sa-Pa-Sa-Pa in the Indian carnatic classical music style. This tuning corresponds to the way violins are tuned for carnatic classical music. This type of mandolin is also used in Bhangra, dance music popular in Punjabi culture. |
Though almost any variety of acoustic mandolin might be adequate for Irish traditional music, virtually all Irish players prefer flat-backed instruments with oval sound holes to the Italian-style bowl-back mandolins or the carved-top mandolins with f-holes favoured by bluegrass mandolinists. The former are often too soft-toned to hold their own in a session (as well as having a tendency to not stay in place on the player's lap), whilst the latter tend to sound harsh and overbearing to the traditional ear. The f-hole mandolin, however, does come into its own in a traditional session, where its brighter tone cuts through the sonic clutter of a pub. Greatly preferred for formal performance and recording are flat-topped "Irish-style" mandolins (reminiscent of the WWI-era Martin Army-Navy mandolin) and carved (arch) top mandolins with oval soundholes, such as the Gibson A-style of the 1920s. |
Noteworthy Irish mandolinists include Andy Irvine (who, like Johnny Moynihan, almost always tunes the top E down to D, to achieve an open tuning of GDAD), Paul Brady, Mick Moloney, Paul Kelly and Claudine Langille. John Sheahan and the late Barney McKenna, respectively fiddle player and tenor banjo player with The Dubliners, are also accomplished Irish mandolin players. The instruments used are either flat-backed, oval hole examples as described above (made by UK luthier Roger Bucknall of Fylde Guitars), or carved-top, oval hole instruments with arched back (made by Stefan Sobell in Northumberland). The Irish guitarist Rory Gallagher often played the mandolin on stage, and he most famously used it in the song "Going To My Hometown." |
Antonio Vivaldi composed a mandolin concerto (Concerto in C major Op.3 6) and two concertos for two mandolins and orchestra. Wolfgang Amadeus Mozart placed it in his 1787 work Don Giovanni and Beethoven created four variations of it. Antonio Maria Bononcini composed La conquista delle Spagne di Scipione Africano il giovane in 1707 and George Frideric Handel composed Alexander Balus in 1748. Others include Giovani Battista Gervasio (Sonata in D major for Mandolin and Basso Continuo), Giuseppe Giuliano (Sonata in D major for Mandolin and Basso Continuo), Emanuele Barbella (Sonata in D major for Mandolin and Basso Continuo), Domenico Scarlatti (Sonata n.54 (K.89) in D minor for Mandolin and Basso Continuo), and Addiego Guerra (Sonata in G major for Mandolin and Basso Continuo). |
The expansion of mandolin use continued after World War II through the late 1960s, and Japan still maintains a strong classical music tradition using mandolins, with active orchestras and university music programs. New orchestras were founded and new orchestral compositions composed. Japanese mandolin orchestras today may consist of up to 40 or 50 members, and can include woodwind, percussion, and brass sections. Japan also maintains an extensive collection of 20th Century mandolin music from Europe and one of the most complete collections of mandolin magazines from mandolin's golden age, purchased by Morishige Takei. |
The bandolim (Portuguese for "mandolin") was a favourite instrument within the Portuguese bourgeoisie of the 19th century, but its rapid spread took it to other places, joining other instruments. Today you can see mandolins as part of the traditional and folk culture of Portuguese singing groups and the majority of the mandolin scene in Portugal is in Madeira Island. Madeira has over 17 active mandolin Orchestras and Tunas. The mandolin virtuoso Fabio Machado is one of Portugal's most accomplished mandolin players. The Portuguese influence brought the mandolin to Brazil. |
The mandolin has been used extensively in the traditional music of England and Scotland for generations. Simon Mayor is a prominent British player who has produced six solo albums, instructional books and DVDs, as well as recordings with his mandolin quartet the Mandolinquents. The instrument has also found its way into British rock music. The mandolin was played by Mike Oldfield (and introduced by Vivian Stanshall) on Oldfield's album Tubular Bells, as well as on a number of his subsequent albums (particularly prominently on Hergest Ridge (1974) and Ommadawn (1975)). It was used extensively by the British folk-rock band Lindisfarne, who featured two members on the instrument, Ray Jackson and Simon Cowe, and whose "Fog on the Tyne" was the biggest selling UK album of 1971-1972. The instrument was also used extensively in the UK folk revival of the 1960s and 1970s with bands such as Fairport Convention and Steeleye Span taking it on as the lead instrument in many of their songs. Maggie May by Rod Stewart, which hit No. 1 on both the British charts and the Billboard Hot 100, also featured Jackson's playing. It has also been used by other British rock musicians. Led Zeppelin's bassist John Paul Jones is an accomplished mandolin player and has recorded numerous songs on mandolin including Going to California and That's the Way; the mandolin part on The Battle of Evermore is played by Jimmy Page, who composed the song. Other Led Zeppelin songs featuring mandolin are Hey Hey What Can I Do, and Black Country Woman. Pete Townshend of The Who played mandolin on the track Mike Post Theme, along with many other tracks on Endless Wire. McGuinness Flint, for whom Graham Lyle played the mandolin on their most successful single, When I'm Dead And Gone, is another example. Lyle was also briefly a member of Ronnie Lane's Slim Chance, and played mandolin on their hit How Come. One of the more prominent early mandolin players in popular music was Robin Williamson in The Incredible String Band. Ian Anderson of Jethro Tull is a highly accomplished mandolin player (beautiful track Pussy Willow), as is his guitarist Martin Barre. The popular song Please Please Please Let Me Get What I Want by The Smiths featured a mandolin solo played by Johnny Marr. More recently, the Glasgow-based band Sons and Daughters featured the mandolin, played by Ailidh Lennon, on tracks such as Fight, Start to End, and Medicine. British folk-punk icons the Levellers also regularly use the mandolin in their songs. Current bands are also beginning to use the Mandolin and its unique sound - such as South London's Indigo Moss who use it throughout their recordings and live gigs. The mandolin has also featured in the playing of Matthew Bellamy in the rock band Muse. It also forms the basis of Paul McCartney's 2007 hit "Dance Tonight." That was not the first time a Beatle played a mandolin, however; that distinction goes to George Harrison on Gone Troppo, the title cut from the 1982 album of the same name. The mandolin is taught in Lanarkshire by the Lanarkshire Guitar and Mandolin Association to over 100 people. Also more recently hard rock supergroup Them Crooked Vultures have been playing a song based primarily using a mandolin. This song was left off their debut album, and features former Led Zeppelin bassist John Paul Jones.[citation needed] |
The mandolin's popularity in the United States was spurred by the success of a group of touring young European musicians known as the Estudiantina Figaro, or in the United States, simply the "Spanish Students." The group landed in the U.S. on January 2, 1880 in New York City, and played in Boston and New York to wildly enthusiastic crowds. Ironically, this ensemble did not play mandolins but rather bandurrias, which are also small, double-strung instruments that resemble the mandolin. The success of the Figaro Spanish Students spawned other groups who imitated their musical style and costumes. An Italian musician, Carlo Curti, hastily started a musical ensemble after seeing the Figaro Spanish Students perform; his group of Italian born Americans called themselves the "Original Spanish Students," counting on the American public to not know the difference between the Spanish bandurrias and Italian mandolins. The imitators' use of mandolins helped to generate enormous public interest in an instrument previously relatively unknown in the United States. |
Mandolin awareness in the United States blossomed in the 1880s, as the instrument became part of a fad that continued into the mid-1920s. According to Clarence L. Partee, the first mandolin made in the United States was made in 1883 or 1884 by Joseph Bohmann, who was an established maker of violins in Chicago. Partee characterized the early instrument as being larger than the European instruments he was used to, with a "peculiar shape" and "crude construction," and said that the quality improved, until American instruments were "superior" to imported instruments. At the time, Partee was using an imported French-made mandolin. |
Instruments were marketed by teacher-dealers, much as the title character in the popular musical The Music Man. Often, these teacher-dealers conducted mandolin orchestras: groups of 4-50 musicians who played various mandolin family instruments. However, alongside the teacher-dealers were serious musicians, working to create a spot for the instrument in classical music, ragtime and jazz. Like the teacher-dealers, they traveled the U.S., recording records, giving performances and teaching individuals and mandolin orchestras. Samuel Siegel played mandolin in Vaudeville and became one of America's preeminent mandolinists. Seth Weeks was an African American who not only taught and performed in the United States, but also in Europe, where he recorded records. Another pioneering African American musician and director who made his start with a mandolin orchestra was composer James Reese Europe. W. Eugene Page toured the country with a group, and was well known for his mandolin and mandola performances. Other names include Valentine Abt, Samuel Adelstein, William Place, Jr., and Aubrey Stauffer. |
The instrument was primarily used in an ensemble setting well into the 1930s, and although the fad died out at the beginning of the 1930s, the instruments that were developed for the orchestra found a new home in bluegrass. The famous Lloyd Loar Master Model from Gibson (1923) was designed to boost the flagging interest in mandolin ensembles, with little success. However, The "Loar" became the defining instrument of bluegrass music when Bill Monroe purchased F-5 S/N 73987 in a Florida barbershop in 1943 and popularized it as his main instrument. |
The mandolin orchestras never completely went away, however. In fact, along with all the other musical forms the mandolin is involved with, the mandolin ensemble (groups usually arranged like the string section of a modern symphony orchestra, with first mandolins, second mandolins, mandolas, mandocellos, mando-basses, and guitars, and sometimes supplemented by other instruments) continues to grow in popularity. Since the mid-nineties, several public-school mandolin-based guitar programs have blossomed around the country, including Fretworks Mandolin and Guitar Orchestra, the first of its kind. The national organization, Classical Mandolin Society of America, founded by Norman Levine, represents these groups. Prominent modern mandolinists and composers for mandolin in the classical music tradition include Samuel Firstman, Howard Fry, Rudy Cipolla, Dave Apollon, Neil Gladd, Evan Marshall, Marilynn Mair and Mark Davis (the Mair-Davis Duo), Brian Israel, David Evans, Emanuil Shynkman, Radim Zenkl, David Del Tredici and Ernst Krenek. |
When Cowan Powers and his family recorded their old-time music from 1924-1926, his daughter Orpha Powers was one of the earliest known southern-music artists to record with the mandolin. By the 1930s, single mandolins were becoming more commonly used in southern string band music, most notably by brother duets such as the sedate Blue Sky Boys (Bill Bolick and Earl Bolick) and the more hard-driving Monroe Brothers (Bill Monroe and Charlie Monroe). However, the mandolin's modern popularity in country music can be directly traced to one man: Bill Monroe, the father of bluegrass music. After the Monroe Brothers broke up in 1939, Bill Monroe formed his own group, after a brief time called the Blue Grass Boys, and completed the transition of mandolin styles from a "parlor" sound typical of brother duets to the modern "bluegrass" style. He joined the Grand Ole Opry in 1939 and its powerful clear-channel broadcast signal on WSM-AM spread his style throughout the South, directly inspiring many musicians to take up the mandolin. Monroe famously played Gibson F-5 mandolin, signed and dated July 9, 1923, by Lloyd Loar, chief acoustic engineer at Gibson. The F-5 has since become the most imitated tonally and aesthetically by modern builders. |
Monroe's style involved playing lead melodies in the style of a fiddler, and also a percussive chording sound referred to as "the chop" for the sound made by the quickly struck and muted strings. He also perfected a sparse, percussive blues style, especially up the neck in keys that had not been used much in country music, notably B and E. He emphasized a powerful, syncopated right hand at the expense of left-hand virtuosity. Monroe's most influential follower of the second generation is Frank Wakefield and nowadays Mike Compton of the Nashville Bluegrass Band and David Long, who often tour as a duet. Tiny Moore of the Texas Playboys developed an electric five-string mandolin and helped popularize the instrument in Western Swing music. |
Other major bluegrass mandolinists who emerged in the early 1950s and are still active include Jesse McReynolds (of Jim and Jesse) who invented a syncopated banjo-roll-like style called crosspicking—and Bobby Osborne of the Osborne Brothers, who is a master of clarity and sparkling single-note runs. Highly respected and influential modern bluegrass players include Herschel Sizemore, Doyle Lawson, and the multi-genre Sam Bush, who is equally at home with old-time fiddle tunes, rock, reggae, and jazz. Ronnie McCoury of the Del McCoury Band has won numerous awards for his Monroe-influenced playing. The late John Duffey of the original Country Gentlemen and later the Seldom Scene did much to popularize the bluegrass mandolin among folk and urban audiences, especially on the east coast and in the Washington, D.C. area. |
Jethro Burns, best known as half of the comedy duo Homer and Jethro, was also the first important jazz mandolinist. Tiny Moore popularized the mandolin in Western swing music. He initially played an 8-string Gibson but switched after 1952 to a 5-string solidbody electric instrument built by Paul Bigsby. Modern players David Grisman, Sam Bush, and Mike Marshall, among others, have worked since the early 1970s to demonstrate the mandolin's versatility for all styles of music. Chris Thile of California is a well-known player, and has accomplished many feats of traditional bluegrass, classical, contemporary pop and rock; the band Nickel Creek featured his playing in its blend of traditional and pop styles, and he now plays in his band Punch Brothers. Most commonly associated with bluegrass, mandolin has been used a lot in country music over the years. Some well-known players include Marty Stuart, Vince Gill, and Ricky Skaggs. |
Mandolin has also been used in blues music, most notably by Ry Cooder, who performed outstanding covers on his very first recordings, Yank Rachell, Johnny "Man" Young, Carl Martin, and Gerry Hundt. Howard Armstrong, who is famous for blues violin, got his start with his father's mandolin and played in string bands similar to the other Tennessee string bands he came into contact with, with band makeup including "mandolins and fiddles and guitars and banjos. And once in a while they would ease a little ukulele in there and a bass fiddle." Other blues players from the era's string bands include Willie Black (Whistler And His Jug Band), Dink Brister, Jim Hill, Charles Johnson, Coley Jones (Dallas String Band), Bobby Leecan (Need More Band), Alfred Martin, Charlie McCoy (1909-1950), Al Miller, Matthew Prater, and Herb Quinn. |
The mandolin has been used occasionally in rock music, first appearing in the psychedelic era of the late 1960s. Levon Helm of The Band occasionally moved from his drum kit to play mandolin, most notably on Rag Mama Rag, Rockin' Chair, and Evangeline. Ian Anderson of Jethro Tull played mandolin on Fat Man, from their second album, Stand Up, and also occasionally on later releases. Rod Stewart's 1971 No. 1 hit Maggie May features a significant mandolin riff. David Grisman played mandolin on two Grateful Dead songs on the American Beauty album, Friend of the Devil and Ripple, which became instant favorites among amateur pickers at jam sessions and campground gatherings. John Paul Jones and Jimmy Page both played mandolin on Led Zeppelin songs. The popular alt rock group Imagine Dragons feature the mandolin on a few of their songs, most prominently being It's Time. Dash Crofts of the soft rock duo Seals and Crofts extensively used mandolin in their repertoire during the 1970s. Styx released the song Boat on the River in 1980, which featured Tommy Shaw on vocals and mandolin. The song didn't chart in the United States but was popular in much of Europe and the Philippines. |
Some rock musicians today use mandolins, often single-stringed electric models rather than double-stringed acoustic mandolins. One example is Tim Brennan of the Irish-American punk rock band Dropkick Murphys. In addition to electric guitar, bass, and drums, the band uses several instruments associated with traditional Celtic music, including mandolin, tin whistle, and Great Highland bagpipes. The band explains that these instruments accentuate the growling sound they favor. The 1991 R.E.M. hit "Losing My Religion" was driven by a few simple mandolin licks played by guitarist Peter Buck, who also played the mandolin in nearly a dozen other songs. The single peaked at No. 4 on the Billboard Hot 100 chart (#1 on the rock and alternative charts), Luther Dickinson of North Mississippi Allstars and The Black Crowes has made frequent use of the mandolin, most notably on the Black Crowes song "Locust Street." Armenian American rock group System of A Down makes extensive use of the mandolin on their 2005 double album Mezmerize/Hypnotize. Pop punk band Green Day has used a mandolin in several occasions, especially on their 2000 album, Warning. Boyd Tinsley, violin player of the Dave Matthews Band has been using an electric mandolin since 2005. Frontman Colin Meloy and guitarist Chris Funk of The Decemberists regularly employ the mandolin in the band's music. Nancy Wilson, rhythm guitarist of Heart, uses a mandolin in Heart's song "Dream of the Archer" from the album Little Queen, as well as in Heart's cover of Led Zeppelin's song "The Battle of Evermore." "Show Me Heaven" by Maria McKee, the theme song to the film Days of Thunder, prominently features a mandolin. |
As in Brazil, the mandolin has played an important role in the Music of Venezuela. It has enjoyed a privileged position as the main melodic instrument in several different regions of the country. Specifically, the eastern states of Sucre, Nueva Esparta, Anzoategui and Monagas have made the mandolin the main instrument in their versions of Joropo as well as Puntos, Jotas, Polos, Fulias, Merengues and Malagueñas. Also, in the west of the country the sound of the mandolin is intrinsically associated with the regional genres of the Venezuelan Andes: Bambucos, Pasillos, Pasodobles, and Waltzes. In the western city of Maracaibo the Mandolin has been played in Decimas, Danzas and Contradanzas Zulianas; in the capital, Caracas, the Merengue Rucaneao, Pasodobles and Waltzes have also been played with mandolin for almost a century. Today, Venezuelan mandolists include an important group of virtuoso players and ensembles such as Alberto Valderrama, Jesus Rengel, Ricardo Sandoval, Saul Vera, and Cristobal Soto. |
To fill this gap in the literature, mandolin orchestras have traditionally played many arrangements of music written for regular orchestras or other ensembles. Some players have sought out contemporary composers to solicit new works. Traditional mandolin orchestras remain especially popular in Japan and Germany, but also exist throughout the United States, Europe and the rest of the world. They perform works composed for mandolin family instruments, or re-orchestrations of traditional pieces. The structure of a contemporary traditional mandolin orchestra consists of: first and second mandolins, mandolas (either octave mandolas, tuned an octave below the mandolin, or tenor mandolas, tuned like the viola), mandocellos (tuned like the cello), and bass instruments (conventional string bass or, rarely, mandobasses). Smaller ensembles, such as quartets composed of two mandolins, mandola, and mandocello, may also be found. |
Insects (from Latin insectum, a calque of Greek ἔντομον [éntomon], "cut into sections") are a class of invertebrates within the arthropod phylum that have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae. They are the most diverse group of animals on the planet, including more than a million described species and representing more than half of all known living organisms. The number of extant species is estimated at between six and ten million, and potentially represent over 90% of the differing animal life forms on Earth. Insects may be found in nearly all environments, although only a small number of species reside in the oceans, a habitat dominated by another arthropod group, crustaceans. |
The life cycles of insects vary but most hatch from eggs. Insect growth is constrained by the inelastic exoskeleton and development involves a series of molts. The immature stages can differ from the adults in structure, habit and habitat, and can include a passive pupal stage in those groups that undergo 4-stage metamorphosis (see holometabolism). Insects that undergo 3-stage metamorphosis lack a pupal stage and adults develop through a series of nymphal stages. The higher level relationship of the Hexapoda is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm (22–28 in). The most diverse insect groups appear to have coevolved with flowering plants. |
Adult insects typically move about by walking, flying, or sometimes swimming (see below, Locomotion). As it allows for rapid yet stable movement, many insects adopt a tripedal gait in which they walk with their legs touching the ground in alternating triangles. Insects are the only invertebrates to have evolved flight. Many insects spend at least part of their lives under water, with larval adaptations that include gills, and some adult insects are aquatic and have adaptations for swimming. Some species, such as water striders, are capable of walking on the surface of water. Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies. Some insects, such as earwigs, show maternal care, guarding their eggs and young. Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over great distances. Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyridae in the beetle order Coleoptera communicate with light. |
Humans regard certain insects as pests, and attempt to control them using insecticides and a host of other techniques. Some insects damage crops by feeding on sap, leaves or fruits. A few parasitic species are pathogenic. Some insects perform complex ecological roles; blow-flies, for example, help consume carrion but also spread diseases. Insect pollinators are essential to the life-cycle of many flowering plant species on which most organisms, including humans, are at least partly dependent; without them, the terrestrial portion of the biosphere (including humans) would be devastated. Many other insects are considered ecologically beneficial as predators and a few provide direct economic benefit. Silkworms and bees have been used extensively by humans for the production of silk and honey, respectively. In some cultures, people eat the larvae or adults of certain insects. |
The word "insect" comes from the Latin word insectum, meaning "with a notched or divided body", or literally "cut into", from the neuter singular perfect passive participle of insectare, "to cut into, to cut up", from in- "into" and secare "to cut"; because insects appear "cut into" three sections. Pliny the Elder introduced the Latin designation as a loan-translation of the Greek word ἔντομος (éntomos) or "insect" (as in entomology), which was Aristotle's term for this class of life, also in reference to their "notched" bodies. "Insect" first appears documented in English in 1601 in Holland's translation of Pliny. Translations of Aristotle's term also form the usual word for "insect" in Welsh (trychfil, from trychu "to cut" and mil, "animal"), Serbo-Croatian (zareznik, from rezati, "to cut"), Russian (насекомое nasekomoje, from seč'/-sekat', "to cut"), etc. |
The higher-level phylogeny of the arthropods continues to be a matter of debate and research. In 2008, researchers at Tufts University uncovered what they believe is the world's oldest known full-body impression of a primitive flying insect, a 300 million-year-old specimen from the Carboniferous period. The oldest definitive insect fossil is the Devonian Rhyniognatha hirsti, from the 396-million-year-old Rhynie chert. It may have superficially resembled a modern-day silverfish insect. This species already possessed dicondylic mandibles (two articulations in the mandible), a feature associated with winged insects, suggesting that wings may already have evolved at this time. Thus, the first insects probably appeared earlier, in the Silurian period. |
Late Carboniferous and Early Permian insect orders include both extant groups, their stem groups, and a number of Paleozoic groups, now extinct. During this era, some giant dragonfly-like forms reached wingspans of 55 to 70 cm (22 to 28 in), making them far larger than any living insect. This gigantism may have been due to higher atmospheric oxygen levels that allowed increased respiratory efficiency relative to today. The lack of flying vertebrates could have been another factor. Most extinct orders of insects developed during the Permian period that began around 270 million years ago. Many of the early groups became extinct during the Permian-Triassic extinction event, the largest mass extinction in the history of the Earth, around 252 million years ago. |
Insects were among the earliest terrestrial herbivores and acted as major selection agents on plants. Plants evolved chemical defenses against this herbivory and the insects, in turn, evolved mechanisms to deal with plant toxins. Many insects make use of these toxins to protect themselves from their predators. Such insects often advertise their toxicity using warning colors. This successful evolutionary pattern has also been used by mimics. Over time, this has led to complex groups of coevolved species. Conversely, some interactions between plants and insects, like pollination, are beneficial to both organisms. Coevolution has led to the development of very specific mutualisms in such systems. |
Insects can be divided into two groups historically treated as subclasses: wingless insects, known as Apterygota, and winged insects, known as Pterygota. The Apterygota consist of the primitively wingless order of the silverfish (Thysanura). Archaeognatha make up the Monocondylia based on the shape of their mandibles, while Thysanura and Pterygota are grouped together as Dicondylia. The Thysanura themselves possibly are not monophyletic, with the family Lepidotrichidae being a sister group to the Dicondylia (Pterygota and the remaining Thysanura). |
Traditional morphology-based or appearance-based systematics have usually given the Hexapoda the rank of superclass,:180 and identified four groups within it: insects (Ectognatha), springtails (Collembola), Protura, and Diplura, the latter three being grouped together as the Entognatha on the basis of internalized mouth parts. Supraordinal relationships have undergone numerous changes with the advent of methods based on evolutionary history and genetic data. A recent theory is that the Hexapoda are polyphyletic (where the last common ancestor was not a member of the group), with the entognath classes having separate evolutionary histories from the Insecta. Many of the traditional appearance-based taxa have been shown to be paraphyletic, so rather than using ranks like subclass, superorder, and infraorder, it has proved better to use monophyletic groupings (in which the last common ancestor is a member of the group). The following represents the best-supported monophyletic groupings for the Insecta. |
Paleoptera and Neoptera are the winged orders of insects differentiated by the presence of hardened body parts called sclerites, and in the Neoptera, muscles that allow their wings to fold flatly over the abdomen. Neoptera can further be divided into incomplete metamorphosis-based (Polyneoptera and Paraneoptera) and complete metamorphosis-based groups. It has proved difficult to clarify the relationships between the orders in Polyneoptera because of constant new findings calling for revision of the taxa. For example, the Paraneoptera have turned out to be more closely related to the Endopterygota than to the rest of the Exopterygota. The recent molecular finding that the traditional louse orders Mallophaga and Anoplura are derived from within Psocoptera has led to the new taxon Psocodea. Phasmatodea and Embiidina have been suggested to form the Eukinolabia. Mantodea, Blattodea, and Isoptera are thought to form a monophyletic group termed Dictyoptera. |
The Exopterygota likely are paraphyletic in regard to the Endopterygota. Matters that have incurred controversy include Strepsiptera and Diptera grouped together as Halteria based on a reduction of one of the wing pairs – a position not well-supported in the entomological community. The Neuropterida are often lumped or split on the whims of the taxonomist. Fleas are now thought to be closely related to boreid mecopterans. Many questions remain in the basal relationships amongst endopterygote orders, particularly the Hymenoptera. |
Though the true dimensions of species diversity remain uncertain, estimates range from 2.6–7.8 million species with a mean of 5.5 million. This probably represents less than 20% of all species on Earth[citation needed], and with only about 20,000 new species of all organisms being described each year, most species likely will remain undescribed for many years unless species descriptions increase in rate. About 850,000–1,000,000 of all described species are insects. Of the 24 orders of insects, four dominate in terms of numbers of described species, with at least 3 million species included in Coleoptera, Diptera, Hymenoptera and Lepidoptera. A recent study estimated the number of beetles at 0.9–2.1 million with a mean of 1.5 million. |
Insects have segmented bodies supported by exoskeletons, the hard outer covering made mostly of chitin. The segments of the body are organized into three distinctive but interconnected units, or tagmata: a head, a thorax and an abdomen. The head supports a pair of sensory antennae, a pair of compound eyes, and, if present, one to three simple eyes (or ocelli) and three sets of variously modified appendages that form the mouthparts. The thorax has six segmented legs—one pair each for the prothorax, mesothorax and the metathorax segments making up the thorax—and, none, two or four wings. The abdomen consists of eleven segments, though in a few species of insects, these segments may be fused together or reduced in size. The abdomen also contains most of the digestive, respiratory, excretory and reproductive internal structures.:22–48 Considerable variation and many adaptations in the body parts of insects occur, especially wings, legs, antenna and mouthparts. |
The head is enclosed in a hard, heavily sclerotized, unsegmented, exoskeletal head capsule, or epicranium, which contains most of the sensing organs, including the antennae, ocellus or eyes, and the mouthparts. Of all the insect orders, Orthoptera displays the most features found in other insects, including the sutures and sclerites. Here, the vertex, or the apex (dorsal region), is situated between the compound eyes for insects with a hypognathous and opisthognathous head. In prognathous insects, the vertex is not found between the compound eyes, but rather, where the ocelli are normally. This is because the primary axis of the head is rotated 90° to become parallel to the primary axis of the body. In some species, this region is modified and assumes a different name.:13 |
The thorax is a tagma composed of three sections, the prothorax, mesothorax and the metathorax. The anterior segment, closest to the head, is the prothorax, with the major features being the first pair of legs and the pronotum. The middle segment is the mesothorax, with the major features being the second pair of legs and the anterior wings. The third and most posterior segment, abutting the abdomen, is the metathorax, which features the third pair of legs and the posterior wings. Each segment is dilineated by an intersegmental suture. Each segment has four basic regions. The dorsal surface is called the tergum (or notum) to distinguish it from the abdominal terga. The two lateral regions are called the pleura (singular: pleuron) and the ventral aspect is called the sternum. In turn, the notum of the prothorax is called the pronotum, the notum for the mesothorax is called the mesonotum and the notum for the metathorax is called the metanotum. Continuing with this logic, the mesopleura and metapleura, as well as the mesosternum and metasternum, are used. |
The abdomen is the largest tagma of the insect, which typically consists of 11–12 segments and is less strongly sclerotized than the head or thorax. Each segment of the abdomen is represented by a sclerotized tergum and sternum. Terga are separated from each other and from the adjacent sterna or pleura by membranes. Spiracles are located in the pleural area. Variation of this ground plan includes the fusion of terga or terga and sterna to form continuous dorsal or ventral shields or a conical tube. Some insects bear a sclerite in the pleural area called a laterotergite. Ventral sclerites are sometimes called laterosternites. During the embryonic stage of many insects and the postembryonic stage of primitive insects, 11 abdominal segments are present. In modern insects there is a tendency toward reduction in the number of the abdominal segments, but the primitive number of 11 is maintained during embryogenesis. Variation in abdominal segment number is considerable. If the Apterygota are considered to be indicative of the ground plan for pterygotes, confusion reigns: adult Protura have 12 segments, Collembola have 6. The orthopteran family Acrididae has 11 segments, and a fossil specimen of Zoraptera has a 10-segmented abdomen. |
The insect outer skeleton, the cuticle, is made up of two layers: the epicuticle, which is a thin and waxy water resistant outer layer and contains no chitin, and a lower layer called the procuticle. The procuticle is chitinous and much thicker than the epicuticle and has two layers: an outer layer known as the exocuticle and an inner layer known as the endocuticle. The tough and flexible endocuticle is built from numerous layers of fibrous chitin and proteins, criss-crossing each other in a sandwich pattern, while the exocuticle is rigid and hardened.:22–24 The exocuticle is greatly reduced in many soft-bodied insects (e.g., caterpillars), especially during their larval stages. |
Insects are the only invertebrates to have developed active flight capability, and this has played an important role in their success.:186 Their muscles are able to contract multiple times for each single nerve impulse, allowing the wings to beat faster than would ordinarily be possible. Having their muscles attached to their exoskeletons is more efficient and allows more muscle connections; crustaceans also use the same method, though all spiders use hydraulic pressure to extend their legs, a system inherited from their pre-arthropod ancestors. Unlike insects, though, most aquatic crustaceans are biomineralized with calcium carbonate extracted from the water. |
The thoracic segments have one ganglion on each side, which are connected into a pair, one pair per segment. This arrangement is also seen in the abdomen but only in the first eight segments. Many species of insects have reduced numbers of ganglia due to fusion or reduction. Some cockroaches have just six ganglia in the abdomen, whereas the wasp Vespa crabro has only two in the thorax and three in the abdomen. Some insects, like the house fly Musca domestica, have all the body ganglia fused into a single large thoracic ganglion. |
At least a few insects have nociceptors, cells that detect and transmit sensations of pain. This was discovered in 2003 by studying the variation in reactions of larvae of the common fruitfly Drosophila to the touch of a heated probe and an unheated one. The larvae reacted to the touch of the heated probe with a stereotypical rolling behavior that was not exhibited when the larvae were touched by the unheated probe. Although nociception has been demonstrated in insects, there is no consensus that insects feel pain consciously |
The salivary glands (element 30 in numbered diagram) in an insect's mouth produce saliva. The salivary ducts lead from the glands to the reservoirs and then forward through the head to an opening called the salivarium, located behind the hypopharynx. By moving its mouthparts (element 32 in numbered diagram) the insect can mix its food with saliva. The mixture of saliva and food then travels through the salivary tubes into the mouth, where it begins to break down. Some insects, like flies, have extra-oral digestion. Insects using extra-oral digestion expel digestive enzymes onto their food to break it down. This strategy allows insects to extract a significant proportion of the available nutrients from the food source.:31 The gut is where almost all of insects' digestion takes place. It can be divided into the foregut, midgut and hindgut. |
Once food leaves the crop, it passes to the midgut (element 13 in numbered diagram), also known as the mesenteron, where the majority of digestion takes place. Microscopic projections from the midgut wall, called microvilli, increase the surface area of the wall and allow more nutrients to be absorbed; they tend to be close to the origin of the midgut. In some insects, the role of the microvilli and where they are located may vary. For example, specialized microvilli producing digestive enzymes may more likely be near the end of the midgut, and absorption near the origin or beginning of the midgut.:32 |
In the hindgut (element 16 in numbered diagram), or proctodaeum, undigested food particles are joined by uric acid to form fecal pellets. The rectum absorbs 90% of the water in these fecal pellets, and the dry pellet is then eliminated through the anus (element 17), completing the process of digestion. The uric acid is formed using hemolymph waste products diffused from the Malpighian tubules (element 20). It is then emptied directly into the alimentary canal, at the junction between the midgut and hindgut. The number of Malpighian tubules possessed by a given insect varies between species, ranging from only two tubules in some insects to over 100 tubules in others.:71–72, 78–80 |
The reproductive system of female insects consist of a pair of ovaries, accessory glands, one or more spermathecae, and ducts connecting these parts. The ovaries are made up of a number of egg tubes, called ovarioles, which vary in size and number by species. The number of eggs that the insect is able to make vary by the number of ovarioles with the rate that eggs can be develop being also influenced by ovariole design. Female insects are able make eggs, receive and store sperm, manipulate sperm from different males, and lay eggs. Accessory glands or glandular parts of the oviducts produce a variety of substances for sperm maintenance, transport and fertilization, as well as for protection of eggs. They can produce glue and protective substances for coating eggs or tough coverings for a batch of eggs called oothecae. Spermathecae are tubes or sacs in which sperm can be stored between the time of mating and the time an egg is fertilized.:880 |
For males, the reproductive system is the testis, suspended in the body cavity by tracheae and the fat body. Most male insects have a pair of testes, inside of which are sperm tubes or follicles that are enclosed within a membranous sac. The follicles connect to the vas deferens by the vas efferens, and the two tubular vasa deferentia connect to a median ejaculatory duct that leads to the outside. A portion of the vas deferens is often enlarged to form the seminal vesicle, which stores the sperm before they are discharged into the female. The seminal vesicles have glandular linings that secrete nutrients for nourishment and maintenance of the sperm. The ejaculatory duct is derived from an invagination of the epidermal cells during development and, as a result, has a cuticular lining. The terminal portion of the ejaculatory duct may be sclerotized to form the intromittent organ, the aedeagus. The remainder of the male reproductive system is derived from embryonic mesoderm, except for the germ cells, or spermatogonia, which descend from the primordial pole cells very early during embryogenesis.:885 |
Insect respiration is accomplished without lungs. Instead, the insect respiratory system uses a system of internal tubes and sacs through which gases either diffuse or are actively pumped, delivering oxygen directly to tissues that need it via their trachea (element 8 in numbered diagram). Since oxygen is delivered directly, the circulatory system is not used to carry oxygen, and is therefore greatly reduced. The insect circulatory system has no veins or arteries, and instead consists of little more than a single, perforated dorsal tube which pulses peristaltically. Toward the thorax, the dorsal tube (element 14) divides into chambers and acts like the insect's heart. The opposite end of the dorsal tube is like the aorta of the insect circulating the hemolymph, arthropods' fluid analog of blood, inside the body cavity.:61–65 Air is taken in through openings on the sides of the abdomen called spiracles. |
There are many different patterns of gas exchange demonstrated by different groups of insects. Gas exchange patterns in insects can range from continuous and diffusive ventilation, to discontinuous gas exchange.:65–68 During continuous gas exchange, oxygen is taken in and carbon dioxide is released in a continuous cycle. In discontinuous gas exchange, however, the insect takes in oxygen while it is active and small amounts of carbon dioxide are released when the insect is at rest. Diffusive ventilation is simply a form of continuous gas exchange that occurs by diffusion rather than physically taking in the oxygen. Some species of insect that are submerged also have adaptations to aid in respiration. As larvae, many insects have gills that can extract oxygen dissolved in water, while others need to rise to the water surface to replenish air supplies which may be held or trapped in special structures. |
The majority of insects hatch from eggs. The fertilization and development takes place inside the egg, enclosed by a shell (chorion) that consists of maternal tissue. In contrast to eggs of other arthropods, most insect eggs are drought resistant. This is because inside the chorion two additional membranes develop from embryonic tissue, the amnion and the serosa. This serosa secretes a cuticle rich in chitin that protects the embryo against desiccation. In Schizophora however the serosa does not develop, but these flies lay their eggs in damp places, such as rotting matter. Some species of insects, like the cockroach Blaptica dubia, as well as juvenile aphids and tsetse flies, are ovoviviparous. The eggs of ovoviviparous animals develop entirely inside the female, and then hatch immediately upon being laid. Some other species, such as those in the genus of cockroaches known as Diploptera, are viviparous, and thus gestate inside the mother and are born alive.:129, 131, 134–135 Some insects, like parasitic wasps, show polyembryony, where a single fertilized egg divides into many and in some cases thousands of separate embryos.:136–137 Insects may be univoltine, bivoltine or multivoltine, i.e. they may have one, two or many broods (generations) in a year. |
Other developmental and reproductive variations include haplodiploidy, polymorphism, paedomorphosis or peramorphosis, sexual dimorphism, parthenogenesis and more rarely hermaphroditism.:143 In haplodiploidy, which is a type of sex-determination system, the offspring's sex is determined by the number of sets of chromosomes an individual receives. This system is typical in bees and wasps. Polymorphism is where a species may have different morphs or forms, as in the oblong winged katydid, which has four different varieties: green, pink and yellow or tan. Some insects may retain phenotypes that are normally only seen in juveniles; this is called paedomorphosis. In peramorphosis, an opposite sort of phenomenon, insects take on previously unseen traits after they have matured into adults. Many insects display sexual dimorphism, in which males and females have notably different appearances, such as the moth Orgyia recens as an exemplar of sexual dimorphism in insects. |
Some insects use parthenogenesis, a process in which the female can reproduce and give birth without having the eggs fertilized by a male. Many aphids undergo a form of parthenogenesis, called cyclical parthenogenesis, in which they alternate between one or many generations of asexual and sexual reproduction. In summer, aphids are generally female and parthenogenetic; in the autumn, males may be produced for sexual reproduction. Other insects produced by parthenogenesis are bees, wasps and ants, in which they spawn males. However, overall, most individuals are female, which are produced by fertilization. The males are haploid and the females are diploid. More rarely, some insects display hermaphroditism, in which a given individual has both male and female reproductive organs. |
Hemimetabolous insects, those with incomplete metamorphosis, change gradually by undergoing a series of molts. An insect molts when it outgrows its exoskeleton, which does not stretch and would otherwise restrict the insect's growth. The molting process begins as the insect's epidermis secretes a new epicuticle inside the old one. After this new epicuticle is secreted, the epidermis releases a mixture of enzymes that digests the endocuticle and thus detaches the old cuticle. When this stage is complete, the insect makes its body swell by taking in a large quantity of water or air, which makes the old cuticle split along predefined weaknesses where the old exocuticle was thinnest.:142 |
Holometabolism, or complete metamorphosis, is where the insect changes in four stages, an egg or embryo, a larva, a pupa and the adult or imago. In these species, an egg hatches to produce a larva, which is generally worm-like in form. This worm-like form can be one of several varieties: eruciform (caterpillar-like), scarabaeiform (grub-like), campodeiform (elongated, flattened and active), elateriform (wireworm-like) or vermiform (maggot-like). The larva grows and eventually becomes a pupa, a stage marked by reduced movement and often sealed within a cocoon. There are three types of pupae: obtect, exarate or coarctate. Obtect pupae are compact, with the legs and other appendages enclosed. Exarate pupae have their legs and other appendages free and extended. Coarctate pupae develop inside the larval skin.:151 Insects undergo considerable change in form during the pupal stage, and emerge as adults. Butterflies are a well-known example of insects that undergo complete metamorphosis, although most insects use this life cycle. Some insects have evolved this system to hypermetamorphosis. |
Many insects possess very sensitive and, or specialized organs of perception. Some insects such as bees can perceive ultraviolet wavelengths, or detect polarized light, while the antennae of male moths can detect the pheromones of female moths over distances of many kilometers. The yellow paper wasp (Polistes versicolor) is known for its wagging movements as a form of communication within the colony; it can waggle with a frequency of 10.6±2.1 Hz (n=190). These wagging movements can signal the arrival of new material into the nest and aggression between workers can be used to stimulate others to increase foraging expeditions. There is a pronounced tendency for there to be a trade-off between visual acuity and chemical or tactile acuity, such that most insects with well-developed eyes have reduced or simple antennae, and vice versa. There are a variety of different mechanisms by which insects perceive sound, while the patterns are not universal, insects can generally hear sound if they can produce it. Different insect species can have varying hearing, though most insects can hear only a narrow range of frequencies related to the frequency of the sounds they can produce. Mosquitoes have been found to hear up to 2 kHz., and some grasshoppers can hear up to 50 kHz. Certain predatory and parasitic insects can detect the characteristic sounds made by their prey or hosts, respectively. For instance, some nocturnal moths can perceive the ultrasonic emissions of bats, which helps them avoid predation.:87–94 Insects that feed on blood have special sensory structures that can detect infrared emissions, and use them to home in on their hosts. |
Some insects display a rudimentary sense of numbers, such as the solitary wasps that prey upon a single species. The mother wasp lays her eggs in individual cells and provides each egg with a number of live caterpillars on which the young feed when hatched. Some species of wasp always provide five, others twelve, and others as high as twenty-four caterpillars per cell. The number of caterpillars is different among species, but always the same for each sex of larva. The male solitary wasp in the genus Eumenes is smaller than the female, so the mother of one species supplies him with only five caterpillars; the larger female receives ten caterpillars in her cell. |
A few insects, such as members of the families Poduridae and Onychiuridae (Collembola), Mycetophilidae (Diptera) and the beetle families Lampyridae, Phengodidae, Elateridae and Staphylinidae are bioluminescent. The most familiar group are the fireflies, beetles of the family Lampyridae. Some species are able to control this light generation to produce flashes. The function varies with some species using them to attract mates, while others use them to lure prey. Cave dwelling larvae of Arachnocampa (Mycetophilidae, Fungus gnats) glow to lure small flying insects into sticky strands of silk. Some fireflies of the genus Photuris mimic the flashing of female Photinus species to attract males of that species, which are then captured and devoured. The colors of emitted light vary from dull blue (Orfelia fultoni, Mycetophilidae) to the familiar greens and the rare reds (Phrixothrix tiemanni, Phengodidae). |
Most insects, except some species of cave crickets, are able to perceive light and dark. Many species have acute vision capable of detecting minute movements. The eyes may include simple eyes or ocelli as well as compound eyes of varying sizes. Many species are able to detect light in the infrared, ultraviolet and the visible light wavelengths. Color vision has been demonstrated in many species and phylogenetic analysis suggests that UV-green-blue trichromacy existed from at least the Devonian period between 416 and 359 million years ago. |
Insects were the earliest organisms to produce and sense sounds. Insects make sounds mostly by mechanical action of appendages. In grasshoppers and crickets, this is achieved by stridulation. Cicadas make the loudest sounds among the insects by producing and amplifying sounds with special modifications to their body and musculature. The African cicada Brevisana brevis has been measured at 106.7 decibels at a distance of 50 cm (20 in). Some insects, such as the Helicoverpa zeamoths, hawk moths and Hedylid butterflies, can hear ultrasound and take evasive action when they sense that they have been detected by bats. Some moths produce ultrasonic clicks that were once thought to have a role in jamming bat echolocation. The ultrasonic clicks were subsequently found to be produced mostly by unpalatable moths to warn bats, just as warning colorations are used against predators that hunt by sight. Some otherwise palatable moths have evolved to mimic these calls. More recently, the claim that some moths can jam bat sonar has been revisited. Ultrasonic recording and high-speed infrared videography of bat-moth interactions suggest the palatable tiger moth really does defend against attacking big brown bats using ultrasonic clicks that jam bat sonar. |
Very low sounds are also produced in various species of Coleoptera, Hymenoptera, Lepidoptera, Mantodea and Neuroptera. These low sounds are simply the sounds made by the insect's movement. Through microscopic stridulatory structures located on the insect's muscles and joints, the normal sounds of the insect moving are amplified and can be used to warn or communicate with other insects. Most sound-making insects also have tympanal organs that can perceive airborne sounds. Some species in Hemiptera, such as the corixids (water boatmen), are known to communicate via underwater sounds. Most insects are also able to sense vibrations transmitted through surfaces. |
Some species use vibrations for communicating within members of the same species, such as to attract mates as in the songs of the shield bug Nezara viridula. Vibrations can also be used to communicate between entirely different species; lycaenid (gossamer-winged butterfly) caterpillars which are myrmecophilous (living in a mutualistic association with ants) communicate with ants in this way. The Madagascar hissing cockroach has the ability to press air through its spiracles to make a hissing noise as a sign of aggression; the Death's-head Hawkmoth makes a squeaking noise by forcing air out of their pharynx when agitated, which may also reduce aggressive worker honey bee behavior when the two are in close proximity. |
Chemical communications in animals rely on a variety of aspects including taste and smell. Chemoreception is the physiological response of a sense organ (i.e. taste or smell) to a chemical stimulus where the chemicals act as signals to regulate the state or activity of a cell. A semiochemical is a message-carrying chemical that is meant to attract, repel, and convey information. Types of semiochemicals include pheromones and kairomones. One example is the butterfly Phengaris arion which uses chemical signals as a form of mimicry to aid in predation. |
In addition to the use of sound for communication, a wide range of insects have evolved chemical means for communication. These chemicals, termed semiochemicals, are often derived from plant metabolites include those meant to attract, repel and provide other kinds of information. Pheromones, a type of semiochemical, are used for attracting mates of the opposite sex, for aggregating conspecific individuals of both sexes, for deterring other individuals from approaching, to mark a trail, and to trigger aggression in nearby individuals. Allomonea benefit their producer by the effect they have upon the receiver. Kairomones benefit their receiver instead of their producer. Synomones benefit the producer and the receiver. While some chemicals are targeted at individuals of the same species, others are used for communication across species. The use of scents is especially well known to have developed in social insects.:96–105 |
Social insects, such as termites, ants and many bees and wasps, are the most familiar species of eusocial animal. They live together in large well-organized colonies that may be so tightly integrated and genetically similar that the colonies of some species are sometimes considered superorganisms. It is sometimes argued that the various species of honey bee are the only invertebrates (and indeed one of the few non-human groups) to have evolved a system of abstract symbolic communication where a behavior is used to represent and convey specific information about something in the environment. In this communication system, called dance language, the angle at which a bee dances represents a direction relative to the sun, and the length of the dance represents the distance to be flown.:309–311 Though perhaps not as advanced as honey bees, bumblebees also potentially have some social communication behaviors. Bombus terrestris, for example, exhibit a faster learning curve for visiting unfamiliar, yet rewarding flowers, when they can see a conspecific foraging on the same species. |
Only insects which live in nests or colonies demonstrate any true capacity for fine-scale spatial orientation or homing. This can allow an insect to return unerringly to a single hole a few millimeters in diameter among thousands of apparently identical holes clustered together, after a trip of up to several kilometers' distance. In a phenomenon known as philopatry, insects that hibernate have shown the ability to recall a specific location up to a year after last viewing the area of interest. A few insects seasonally migrate large distances between different geographic regions (e.g., the overwintering areas of the Monarch butterfly).:14 |
The eusocial insects build nest, guard eggs, and provide food for offspring full-time (see Eusociality). Most insects, however, lead short lives as adults, and rarely interact with one another except to mate or compete for mates. A small number exhibit some form of parental care, where they will at least guard their eggs, and sometimes continue guarding their offspring until adulthood, and possibly even feeding them. Another simple form of parental care is to construct a nest (a burrow or an actual construction, either of which may be simple or complex), store provisions in it, and lay an egg upon those provisions. The adult does not contact the growing offspring, but it nonetheless does provide food. This sort of care is typical for most species of bees and various types of wasps. |
Insects are the only group of invertebrates to have developed flight. The evolution of insect wings has been a subject of debate. Some entomologists suggest that the wings are from paranotal lobes, or extensions from the insect's exoskeleton called the nota, called the paranotal theory. Other theories are based on a pleural origin. These theories include suggestions that wings originated from modified gills, spiracular flaps or as from an appendage of the epicoxa. The epicoxal theory suggests the insect wings are modified epicoxal exites, a modified appendage at the base of the legs or coxa. In the Carboniferous age, some of the Meganeura dragonflies had as much as a 50 cm (20 in) wide wingspan. The appearance of gigantic insects has been found to be consistent with high atmospheric oxygen. The respiratory system of insects constrains their size, however the high oxygen in the atmosphere allowed larger sizes. The largest flying insects today are much smaller and include several moth species such as the Atlas moth and the White Witch (Thysania agrippina). |
Many adult insects use six legs for walking and have adopted a tripedal gait. The tripedal gait allows for rapid walking while always having a stable stance and has been studied extensively in cockroaches. The legs are used in alternate triangles touching the ground. For the first step, the middle right leg and the front and rear left legs are in contact with the ground and move the insect forward, while the front and rear right leg and the middle left leg are lifted and moved forward to a new position. When they touch the ground to form a new stable triangle the other legs can be lifted and brought forward in turn and so on. The purest form of the tripedal gait is seen in insects moving at high speeds. However, this type of locomotion is not rigid and insects can adapt a variety of gaits. For example, when moving slowly, turning, or avoiding obstacles, four or more feet may be touching the ground. Insects can also adapt their gait to cope with the loss of one or more limbs. |
Cockroaches are among the fastest insect runners and, at full speed, adopt a bipedal run to reach a high velocity in proportion to their body size. As cockroaches move very quickly, they need to be video recorded at several hundred frames per second to reveal their gait. More sedate locomotion is seen in the stick insects or walking sticks (Phasmatodea). A few insects have evolved to walk on the surface of the water, especially members of the Gerridae family, commonly known as water striders. A few species of ocean-skaters in the genus Halobates even live on the surface of open oceans, a habitat that has few insect species. |
Many of these species have adaptations to help in under-water locomotion. Water beetles and water bugs have legs adapted into paddle-like structures. Dragonfly naiads use jet propulsion, forcibly expelling water out of their rectal chamber. Some species like the water striders are capable of walking on the surface of water. They can do this because their claws are not at the tips of the legs as in most insects, but recessed in a special groove further up the leg; this prevents the claws from piercing the water's surface film. Other insects such as the Rove beetle Stenus are known to emit pygidial gland secretions that reduce surface tension making it possible for them to move on the surface of water by Marangoni propulsion (also known by the German term Entspannungsschwimmen). |
Insect ecology is the scientific study of how insects, individually or as a community, interact with the surrounding environment or ecosystem.:3 Insects play one of the most important roles in their ecosystems, which includes many roles, such as soil turning and aeration, dung burial, pest control, pollination and wildlife nutrition. An example is the beetles, which are scavengers that feed on dead animals and fallen trees and thereby recycle biological materials into forms found useful by other organisms. These insects, and others, are responsible for much of the process by which topsoil is created.:3, 218–228 |
Camouflage is an important defense strategy, which involves the use of coloration or shape to blend into the surrounding environment. This sort of protective coloration is common and widespread among beetle families, especially those that feed on wood or vegetation, such as many of the leaf beetles (family Chrysomelidae) or weevils. In some of these species, sculpturing or various colored scales or hairs cause the beetle to resemble bird dung or other inedible objects. Many of those that live in sandy environments blend in with the coloration of the substrate. Most phasmids are known for effectively replicating the forms of sticks and leaves, and the bodies of some species (such as O. macklotti and Palophus centaurus) are covered in mossy or lichenous outgrowths that supplement their disguise. Some species have the ability to change color as their surroundings shift (B. scabrinota, T. californica). In a further behavioral adaptation to supplement crypsis, a number of species have been noted to perform a rocking motion where the body is swayed from side to side that is thought to reflect the movement of leaves or twigs swaying in the breeze. Another method by which stick insects avoid predation and resemble twigs is by feigning death (catalepsy), where the insect enters a motionless state that can be maintained for a long period. The nocturnal feeding habits of adults also aids Phasmatodea in remaining concealed from predators. |
Another defense that often uses color or shape to deceive potential enemies is mimicry. A number of longhorn beetles (family Cerambycidae) bear a striking resemblance to wasps, which helps them avoid predation even though the beetles are in fact harmless. Batesian and Müllerian mimicry complexes are commonly found in Lepidoptera. Genetic polymorphism and natural selection give rise to otherwise edible species (the mimic) gaining a survival advantage by resembling inedible species (the model). Such a mimicry complex is referred to as Batesian and is most commonly known by the mimicry by the limenitidine Viceroy butterfly of the inedible danaine Monarch. Later research has discovered that the Viceroy is, in fact more toxic than the Monarch and this resemblance should be considered as a case of Müllerian mimicry. In Müllerian mimicry, inedible species, usually within a taxonomic order, find it advantageous to resemble each other so as to reduce the sampling rate by predators who need to learn about the insects' inedibility. Taxa from the toxic genus Heliconius form one of the most well known Müllerian complexes. |
Chemical defense is another important defense found amongst species of Coleoptera and Lepidoptera, usually being advertised by bright colors, such as the Monarch butterfly. They obtain their toxicity by sequestering the chemicals from the plants they eat into their own tissues. Some Lepidoptera manufacture their own toxins. Predators that eat poisonous butterflies and moths may become sick and vomit violently, learning not to eat those types of species; this is actually the basis of Müllerian mimicry. A predator who has previously eaten a poisonous lepidopteran may avoid other species with similar markings in the future, thus saving many other species as well. Some ground beetles of the Carabidae family can spray chemicals from their abdomen with great accuracy, to repel predators. |
Pollination is the process by which pollen is transferred in the reproduction of plants, thereby enabling fertilisation and sexual reproduction. Most flowering plants require an animal to do the transportation. While other animals are included as pollinators, the majority of pollination is done by insects. Because insects usually receive benefit for the pollination in the form of energy rich nectar it is a grand example of mutualism. The various flower traits (and combinations thereof) that differentially attract one type of pollinator or another are known as pollination syndromes. These arose through complex plant-animal adaptations. Pollinators find flowers through bright colorations, including ultraviolet, and attractant pheromones. The study of pollination by insects is known as anthecology. |
Many insects are considered pests by humans. Insects commonly regarded as pests include those that are parasitic (e.g. lice, bed bugs), transmit diseases (mosquitoes, flies), damage structures (termites), or destroy agricultural goods (locusts, weevils). Many entomologists are involved in various forms of pest control, as in research for companies to produce insecticides, but increasingly rely on methods of biological pest control, or biocontrol. Biocontrol uses one organism to reduce the population density of another organism — the pest — and is considered a key element of integrated pest management. |
Although pest insects attract the most attention, many insects are beneficial to the environment and to humans. Some insects, like wasps, bees, butterflies and ants, pollinate flowering plants. Pollination is a mutualistic relationship between plants and insects. As insects gather nectar from different plants of the same species, they also spread pollen from plants on which they have previously fed. This greatly increases plants' ability to cross-pollinate, which maintains and possibly even improves their evolutionary fitness. This ultimately affects humans since ensuring healthy crops is critical to agriculture. As well as pollination ants help with seed distribution of plants. This helps to spread the plants which increases plant diversity. This leads to an overall better environment. A serious environmental problem is the decline of populations of pollinator insects, and a number of species of insects are now cultured primarily for pollination management in order to have sufficient pollinators in the field, orchard or greenhouse at bloom time.:240–243 Another solution, as shown in Delaware, has been to raise native plants to help support native pollinators like L. vierecki. Insects also produce useful substances such as honey, wax, lacquer and silk. Honey bees have been cultured by humans for thousands of years for honey, although contracting for crop pollination is becoming more significant for beekeepers. The silkworm has greatly affected human history, as silk-driven trade established relationships between China and the rest of the world. |
Insectivorous insects, or insects which feed on other insects, are beneficial to humans because they eat insects that could cause damage to agriculture and human structures. For example, aphids feed on crops and cause problems for farmers, but ladybugs feed on aphids, and can be used as a means to get significantly reduce pest aphid populations. While birds are perhaps more visible predators of insects, insects themselves account for the vast majority of insect consumption. Ants also help control animal populations by consuming small vertebrates. Without predators to keep them in check, insects can undergo almost unstoppable population explosions.:328–348:400 |
Insects play important roles in biological research. For example, because of its small size, short generation time and high fecundity, the common fruit fly Drosophila melanogaster is a model organism for studies in the genetics of higher eukaryotes. D. melanogaster has been an essential part of studies into principles like genetic linkage, interactions between genes, chromosomal genetics, development, behavior and evolution. Because genetic systems are well conserved among eukaryotes, understanding basic cellular processes like DNA replication or transcription in fruit flies can help to understand those processes in other eukaryotes, including humans. The genome of D. melanogaster was sequenced in 2000, reflecting the organism's important role in biological research. It was found that 70% of the fly genome is similar to the human genome, supporting the evolution theory. |
In some cultures, insects, especially deep-fried cicadas, are considered to be delicacies, while in other places they form part of the normal diet. Insects have a high protein content for their mass, and some authors suggest their potential as a major source of protein in human nutrition.:10–13 In most first-world countries, however, entomophagy (the eating of insects), is taboo. Since it is impossible to entirely eliminate pest insects from the human food chain, insects are inadvertently present in many foods, especially grains. Food safety laws in many countries do not prohibit insect parts in food, but rather limit their quantity. According to cultural materialist anthropologist Marvin Harris, the eating of insects is taboo in cultures that have other protein sources such as fish or livestock. |
Scarab beetles held religious and cultural symbolism in Old Egypt, Greece and some shamanistic Old World cultures. The ancient Chinese regarded cicadas as symbols of rebirth or immortality. In Mesopotamian literature, the epic poem of Gilgamesh has allusions to Odonata which signify the impossibility of immortality. Amongst the Aborigines of Australia of the Arrernte language groups, honey ants and witchety grubs served as personal clan totems. In the case of the 'San' bush-men of the Kalahari, it is the praying mantis which holds much cultural significance including creation and zen-like patience in waiting.:9 |
Even though there is a broad scientific agreement that essentialist and typological conceptualizations of race are untenable, scientists around the world continue to conceptualize race in widely differing ways, some of which have essentialist implications. While some researchers sometimes use the concept of race to make distinctions among fuzzy sets of traits, others in the scientific community suggest that the idea of race often is used in a naive or simplistic way,[page needed] and argue that, among humans, race has no taxonomic significance by pointing out that all living humans belong to the same species, Homo sapiens, and subspecies, Homo sapiens sapiens. |
There is a wide consensus that the racial categories that are common in everyday usage are socially constructed, and that racial groups cannot be biologically defined. Nonetheless, some scholars argue that racial categories obviously correlate with biological traits (e.g. phenotype) to some degree, and that certain genetic markers have varying frequencies among human populations, some of which correspond more or less to traditional racial groupings. For this reason, there is no current consensus about whether racial categories can be considered to have significance for understanding human genetic variation. |
When people define and talk about a particular conception of race, they create a social reality through which social categorization is achieved. In this sense, races are said to be social constructs. These constructs develop within various legal, economic, and sociopolitical contexts, and may be the effect, rather than the cause, of major social situations. While race is understood to be a social construct by many, most scholars agree that race has real material effects in the lives of people through institutionalized practices of preference and discrimination. |
Socioeconomic factors, in combination with early but enduring views of race, have led to considerable suffering within disadvantaged racial groups. Racial discrimination often coincides with racist mindsets, whereby the individuals and ideologies of one group come to perceive the members of an outgroup as both racially defined and morally inferior. As a result, racial groups possessing relatively little power often find themselves excluded or oppressed, while hegemonic individuals and institutions are charged with holding racist attitudes. Racism has led to many instances of tragedy, including slavery and genocide. |
In some countries, law enforcement uses race to profile suspects. This use of racial categories is frequently criticized for perpetuating an outmoded understanding of human biological variation, and promoting stereotypes. Because in some societies racial groupings correspond closely with patterns of social stratification, for social scientists studying social inequality, race can be a significant variable. As sociological factors, racial categories may in part reflect subjective attributions, self-identities, and social institutions. |
Groups of humans have always identified themselves as distinct from neighboring groups, but such differences have not always been understood to be natural, immutable and global. These features are the distinguishing features of how the concept of race is used today. In this way the idea of race as we understand it today came about during the historical process of exploration and conquest which brought Europeans into contact with groups from different continents, and of the ideology of classification and typology found in the natural sciences. |
The European concept of "race", along with many of the ideas now associated with the term, arose at the time of the scientific revolution, which introduced and privileged the study of natural kinds, and the age of European imperialism and colonization which established political relations between Europeans and peoples with distinct cultural and political traditions. As Europeans encountered people from different parts of the world, they speculated about the physical, social, and cultural differences among various human groups. The rise of the Atlantic slave trade, which gradually displaced an earlier trade in slaves from throughout the world, created a further incentive to categorize human groups in order to justify the subordination of African slaves. Drawing on Classical sources and upon their own internal interactions — for example, the hostility between the English and Irish powerfully influenced early European thinking about the differences between people — Europeans began to sort themselves and others into groups based on physical appearance, and to attribute to individuals belonging to these groups behaviors and capacities which were claimed to be deeply ingrained. A set of folk beliefs took hold that linked inherited physical differences between groups to inherited intellectual, behavioral, and moral qualities. Similar ideas can be found in other cultures, for example in China, where a concept often translated as "race" was associated with supposed common descent from the Yellow Emperor, and used to stress the unity of ethnic groups in China. Brutal conflicts between ethnic groups have existed throughout history and across the world. |
The first post-Classical published classification of humans into distinct races seems to be François Bernier's Nouvelle division de la terre par les différents espèces ou races qui l'habitent ("New division of Earth by the different species or races which inhabit it"), published in 1684. In the 18th century the differences among human groups became a focus of scientific investigation. But the scientific classification of phenotypic variation was frequently coupled with racist ideas about innate predispositions of different groups, always attributing the most desirable features to the White, European race and arranging the other races along a continuum of progressively undesirable attributes. The 1735 classification of Carl Linnaeus, inventor of zoological taxonomy, divided the human race Homo sapiens into continental varieties of europaeus, asiaticus, americanus, and afer, each associated with a different humour: sanguine, melancholic, choleric, and phlegmatic, respectively. Homo sapiens europaeus was described as active, acute, and adventurous, whereas Homo sapiens afer was said to be crafty, lazy, and careless. |
The 1775 treatise "The Natural Varieties of Mankind", by Johann Friedrich Blumenbach proposed five major divisions: the Caucasoid race, Mongoloid race, Ethiopian race (later termed Negroid, and not to be confused with the narrower Ethiopid race), American Indian race, and Malayan race, but he did not propose any hierarchy among the races. Blumenbach also noted the graded transition in appearances from one group to adjacent groups and suggested that "one variety of mankind does so sensibly pass into the other, that you cannot mark out the limits between them". |
From the 17th through 19th centuries, the merging of folk beliefs about group differences with scientific explanations of those differences produced what one scholar has called an "ideology of race". According to this ideology, races are primordial, natural, enduring and distinct. It was further argued that some groups may be the result of mixture between formerly distinct populations, but that careful study could distinguish the ancestral races that had combined to produce admixed groups. Subsequent influential classifications by Georges Buffon, Petrus Camper and Christoph Meiners all classified "Negros" as inferior to Europeans. In the United States the racial theories of Thomas Jefferson were influential. He saw Africans as inferior to Whites especially in regards to their intellect, and imbued with unnatural sexual appetites, but described Native Americans as equals to whites. |
In the last two decades of the 18th century, the theory of polygenism, the belief that different races had evolved separately in each continent and shared no common ancestor, was advocated in England by historian Edward Long and anatomist Charles White, in Germany by ethnographers Christoph Meiners and Georg Forster, and in France by Julien-Joseph Virey. In the US, Samuel George Morton, Josiah Nott and Louis Agassiz promoted this theory in the mid-nineteenth century. Polygenism was popular and most widespread in the 19th century, culminating in the founding of the Anthropological Society of London (1863) during the period of the American Civil War, in opposition to the Ethnological Society, which had abolitionist sympathies. |
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