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Africanized bee

Africanized bee

Overview
Africanized honey bees, known colloquially as "killer bees", are a hybrid variety of the European honeybee (Apis mellifera), generated by a man-made breeding of the African honey bee
African bee
The African honey bee is a subspecies of the Western honey bee. It is native to central and southern Africa, though at the southern extreme it is replaced by the Cape honey bee, Apis mellifera capensis....

, A. m. scutellata, with various European honey bees such as the Italian bee A. m. ligustica
Italian bee
Apis mellifera ligustica is the Italian bee which is a sub-species of the western honey bee .- Origin :The Italian honey bee is thought to originate from the continental part of Italy, South of the Alps, and North of Sicily...

and A. m. iberiensis. These bees are far more aggressive than the European subspecies. Small swarms of Africanized bees are capable of taking over European honey bee hives by invading the hive and establishing their own queen after killing the European queen.

The Africanized honey bees in the Western Hemisphere
Western Hemisphere
The Western Hemisphere or western hemisphere is mainly used as a geographical term for the half of the Earth that lies west of the Prime Meridian and east of the Antimeridian , the other half being called the Eastern Hemisphere.In this sense, the western hemisphere consists of the western portions...

 are descended from 26 Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

n queen bee
Queen bee
The term queen bee is typically used to refer to an adult, mated female that lives in a honey bee colony or hive; she is usually the mother of most, if not all, the bees in the hive. The queens are developed from larvae selected by worker bees and specially fed in order to become sexually mature...

s (A.
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Encyclopedia
Africanized honey bees, known colloquially as "killer bees", are a hybrid variety of the European honeybee (Apis mellifera), generated by a man-made breeding of the African honey bee
African bee
The African honey bee is a subspecies of the Western honey bee. It is native to central and southern Africa, though at the southern extreme it is replaced by the Cape honey bee, Apis mellifera capensis....

, A. m. scutellata, with various European honey bees such as the Italian bee A. m. ligustica
Italian bee
Apis mellifera ligustica is the Italian bee which is a sub-species of the western honey bee .- Origin :The Italian honey bee is thought to originate from the continental part of Italy, South of the Alps, and North of Sicily...

and A. m. iberiensis. These bees are far more aggressive than the European subspecies. Small swarms of Africanized bees are capable of taking over European honey bee hives by invading the hive and establishing their own queen after killing the European queen.

History


The Africanized honey bees in the Western Hemisphere
Western Hemisphere
The Western Hemisphere or western hemisphere is mainly used as a geographical term for the half of the Earth that lies west of the Prime Meridian and east of the Antimeridian , the other half being called the Eastern Hemisphere.In this sense, the western hemisphere consists of the western portions...

 are descended from 26 Tanzania
Tanzania
The United Republic of Tanzania is a country in East Africa bordered by Kenya and Uganda to the north, Rwanda, Burundi, and the Democratic Republic of the Congo to the west, and Zambia, Malawi, and Mozambique to the south. The country's eastern borders lie on the Indian Ocean.Tanzania is a state...

n queen bee
Queen bee
The term queen bee is typically used to refer to an adult, mated female that lives in a honey bee colony or hive; she is usually the mother of most, if not all, the bees in the hive. The queens are developed from larvae selected by worker bees and specially fed in order to become sexually mature...

s (A. m. scutellata) accidentally released by a replacement bee-keeper in 1957 near Rio Claro
Rio Claro
Rio Claro may refer to:-Cities:*Rio Claro, Trinidad and Tobago, the largest town in southeastern Trinidad and Tobago...

, São Paulo
São Paulo (state)
São Paulo is a state in Brazil. It is the major industrial and economic powerhouse of the Brazilian economy. Named after Saint Paul, São Paulo has the largest population, industrial complex, and economic production in the country. It is the richest state in Brazil...

, in the southeast of Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, from hives operated by biologist
Biologist
A biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...

 Warwick E. Kerr
Warwick Estevam Kerr
Warwick Estevam Kerr is a Brazilian agricultural engineer, geneticist, entomologist, professor and scientific leader, notable for his discoveries in the genetics and sex determination of bees. The Africanized bee in the western hemisphere is directly descended from 26 Tanzanian queen bees Warwick...

, who had interbred honey bees from Europe and southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...

. Hives containing these particular queens were noted to be especially defensive. Kerr was attempting to breed a strain of bees that would produce more honey and be better adapted to tropical
Tropics
The tropics is a region of the Earth surrounding the Equator. It is limited in latitude by the Tropic of Cancer in the northern hemisphere at approximately  N and the Tropic of Capricorn in the southern hemisphere at  S; these latitudes correspond to the axial tilt of the Earth...

 conditions (i.e., more productive) than the European bees used in South America and southern North America. The hives the bees were released from had special excluder grates to prevent the larger queen bees and drones from getting out and mating with local (non-African) queens and drones. However, following the accidental release, the African queens and drones mated with local queens and drones, and their descendants have since spread throughout the Americas.

The African hybrid bees have become the preferred types of bee for beekeeping
Beekeeping
Beekeeping is the maintenance of honey bee colonies, commonly in hives, by humans. A beekeeper keeps bees in order to collect honey and other products of the hive , to pollinate crops, or to produce bees for sale to other beekeepers...

 in Central America and in tropical areas of South America because of improved productivity. However, in most areas the African hybrid is initially feared because it tends to retain certain behavioral traits from its African ancestors that make it less desirable for domestic beekeeping. Specifically (as compared with the European bee types), the African bee:
  • Tends to swarm more frequently and go farther than other types of honeybees.
  • Is more likely to migrate as part of a seasonal response to lowered food supply.
  • Is more likely to "abscond"—the entire colony leaves the hive and relocates—in response to stress.
  • Has greater defensiveness when in a resting swarm, compared to other honey bee types.
  • Lives more often in ground cavities than the European types.
  • Guards the hive aggressively, with a larger alarm zone around the hive.
  • Has a higher proportion of "guard" bees within the hive.
  • Deploys in greater numbers for defense and pursues perceived threats over much longer distances from the hive.
  • Cannot survive extended periods of forage
    Forage
    Forage is plant material eaten by grazing livestock.Historically the term forage has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially...

     deprivation, preventing introduction into areas with harsh winters or extremely dry late summers.

Geographic spread



As of 2002, the Africanized honeybees had spread from Brazil south to northern Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

 and north to Central America, Trinidad (West Indies), Mexico, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

, New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...

, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, and southern California. Their expansion stopped for a time at eastern Texas, possibly due to the large number of European-bee beekeepers in the area. However, discoveries of the bees in southern Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...

 indicate this species of bee has penetrated this barrier, or has come as a swarm aboard a ship. In June 2005, it was discovered that the bees had penetrated the border of Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 and had spread into southwest Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...

. On September 11, 2007, Commissioner Bob Odom of the Department of Agriculture and Forestry said that Africanized honey bees established themselves in the New Orleans area. In February 2009, Africanized honeybees were found in southern Utah. In October 2010, a 73-year-old man was killed by a swarm of Africanized honey bees while clearing brush on his south Georgia
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...

 property, as determined by Georgia's Department of Agriculture. It is the first time state officials have recorded that such bees exist in Georgia.

In tropical climates they compete effectively against European bees and, at their peak rate of expansion, they spread north at a rate of almost two kilometers (about one mile) a day. There were discussions about slowing the spread by placing large numbers of docile European-strain hives in strategic locations, particularly at the Isthmus of Panama
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country of Panama and the Panama Canal...

, but various national and international agricultural departments were unable to prevent the bees' expansion. Current knowledge of the genetics of these bees suggests that such a strategy, had it been attempted, would not have been successful.

As the Africanized honeybee migrates further north, colonies are interbreeding with European honeybees. There are now relatively stable geographic zones in which either African bees dominate, a mix of African and European bees is present, or only non-African bees are found (as in southern South America or northern North America).

African honeybees abscond (abandon the hive and any food store to start over in a new location) more readily than European honeybees. This is not necessarily a severe loss in tropical climates where plants bloom all year but in more temperate climates it can leave the colony with insufficient stores to survive the winter. Thus Africanized bees are expected to be a hazard mostly in the Southern States
Southern United States
The Southern United States—commonly referred to as the American South, Dixie, or simply the South—constitutes a large distinctive area in the southeastern and south-central United States...

 of the United States, reaching as far north as the Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...

 in the east. The cold-weather limits of the African bee have driven some professional bee breeders from Southern California into the harsher wintering locales of the northern Sierra Nevada and southern Cascade Range
Cascade Range
The Cascade Range is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, and the notable volcanoes known as the High Cascades...

. This is a more difficult area to prepare bees for early pollination
Pollination management
Pollination Management is the label for horticultural practices that accomplish or enhance pollination of a crop, to improve yield or quality, by understanding of the particular crop's pollination needs, and by knowledgeable management of pollenizers, pollinators, and pollination...

 placement in, such as is required for the production of almond
Almond
The almond , is a species of tree native to the Middle East and South Asia. Almond is also the name of the edible and widely cultivated seed of this tree...

s. The reduced available winter forage in northern California means that bees must be fed for early spring buildup.

The arrival of African honeybees in Central America is a threat to the ancient art of keeping stingless bee
Stingless bee
Stingless bees, sometimes called stingless honey bees or simply meliponines, are a large group of bees, comprising the tribe Meliponini . They belong in the family Apidae, and are closely related to common honey bees, carpenter bees, orchid bees and bumblebees...

s in log gums even though they do not interbreed or directly compete with the stingless bees. The honey productivity of the African bees so far exceeds the productivity of the native stingless bees that economic pressures force beekeepers to switch. African honeybees are considered an invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

 in many regions.

Morphology and genetics


The popular term 'Killer bee' has only limited scientific meaning today because there is no generally accepted fraction of genetic contribution used to establish a cut-off. While the native African bees are smaller, and build smaller comb cells than the European bee, their hybrids are not smaller. They do have slightly shorter wings, which can be reliably recognized only by performing a statistical analysis on micro-measurements of a substantial sample. One problem with this test is that there is also an Egyptian bee
Apis mellifera lamarckii
Lamarck's honey bee or the Egyptian honey bee is a subspecies of honey bee native to the Nile valley of Egypt and Sudan, named after Jean-Baptiste Lamarck. It is considered defensive, low in honey yield and exhibiting good hygienic behavior. It is a dark honey bee with yellow abdomen, and is a...

, present in the southeastern United States, that has the same morphology. Currently testing techniques have moved away from external measurements to DNA analysis, but this means the test can only be done by a sophisticated laboratory. Molecular diagnostics using the mitochondrial DNA
Mitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...

 (mtDNA) cytochrome b gene can differentiate A. m. scutellata from other A. mellifera lineages, though mtDNA only allows one to detect an Africanized colony that has an Africanized queen, and not colonies where a European queen has mated with Africanized drones.

There are two lineages of African bees in the Americas: actual matrilinial descendants of the original escaped queens and a much smaller number that are African through hybridization. The matrilinial descendants carry African mtDNA, but partially European nuclear DNA, while the bees that are African through hybridization carry European mtDNA, and partially African nuclear DNA. The matrilinial descendants are in the vast majority. This is supported by DNA analyses performed on the bees as they spread northwards; those that were at the "vanguard" were over 90% African mtDNA, indicating an unbroken matriline (Smith et al., 1989), but after several years in residence in an area interbreeding with the local European strains, as in Brazil, the overall representation of African mtDNA drops to some degree. However, these latter hybrid lines (with European mtDNA) do not appear to propagate themselves well or persist. Population genetics analysis of Africanized honey bees in the United States, using a materially inherited genetic marker, found 12 distinct mitotypes, and the amount of genetic variation observed supports the idea that there has been multiple introductions of AHB into the United States.

Consequences of selection


The chief difference between the European races or subspecies of bees kept by American beekeepers and the African stock is attributable to selective breeding. The most common race used in North America today is the Italian bee, Apis mellifera ligustica, which has been used for several thousand years in some parts of the world and in the Americas since the arrival of the early European colonists. Beekeepers have tended to eliminate the fierce strains, and the entire race of bees has thus been gentled by selective breeding
Selective breeding
Selective breeding is the process of breeding plants and animals for particular genetic traits. Typically, strains that are selectively bred are domesticated, and the breeding is sometimes done by a professional breeder. Bred animals are known as breeds, while bred plants are known as varieties,...

.

In central and southern Africa, bees have had to defend themselves against other aggressive insects, as well as honey badgers, an animal that also will destroy hives if the bees are not sufficiently defensive. In addition, there was formerly no tradition of beekeeping, only bee robbing. When one wanted honey, one would seek out a bee tree and kill the colony, or at least steal its honey. The colony most likely to survive either animal or human attacks was the fiercest one. These hardy bees had to adapt to the hostile environment of sub-saharan Africa—surviving prolonged droughts and fighting for nectar. Thus the African bee has been naturally selected
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

 for ferocity.

Defensiveness


African bees are characterized by greater defensiveness in established hives than European honey bee
European honey bee
The Western honey bee or European honey bee is a species of honey bee. The genus Apis is Latin for "bee", and mellifera comes from Latin melli- "honey" and ferre "to bear"—hence the scientific name means "honey-bearing bee"...

s. They are more likely to attack a perceived threat and, when they do so, attack relentlessly in larger numbers. Also, they have been known to pursue their threat for over a mile. This aggressively protective behavior has been termed by scientists as hyper-defensive behavior. This defensiveness has earned them the nickname "killer bees," the aptness of which is debated. Over the decades, several deaths in the Americas have been attributed to African bees. The venom of an African bee is no more potent than that of a European honey bee, but since the former tends to sting in greater numbers, the number of deaths from them are greater than from the European honey bee. However, allergic reaction to bee venom
Apitoxin
Apitoxin, or honey bee venom, is a bitter colorless liquid. The active portion of the venom is a complex mixture of proteins, which causes local inflammation and acts as an anticoagulant. The venom is produced in the abdomen of worker bees from a mixture of acidic and basic secretions. Apitoxin...

 from any bee can kill a person, and it is difficult to estimate how many more people have died due to the presence of African bees.

Most human incidents with African bees occur within two or three years of the bees' arrival and then subside. Beekeepers can greatly reduce this problem by culling the queens of aggressive strains and breeding gentler stock. Beekeepers keep A. m. scutellata in South Africa using common beekeeping practices without excessive problems.

Fear factor


The African bee is widely feared by the public, a reaction that has been amplified by sensationalist movies (such as The Swarm and The Deadly Bees
The Deadly Bees
The Deadly Bees is a 1966 British horror–thriller film based on H.F. Heard's 1941 novel A Taste for Honey. It was directed by Freddie Francis, and stars Suzanna Leigh, Guy Doleman, and Frank Finlay. It was released theatrically in the United States in 1967...

) and some of the media reports. Stings from African bees kill 1–2 people per year in the United States.

As the bee spreads through Florida, a densely populated state, officials worry that public fear may force misguided efforts to combat them.
The much smaller and much more aggressive South American stingless bee Trigona spinipes
Trigona spinipes
Trigona spinipes is a species of stingless bee. It occurs in Brazil, where it is called arapuá, irapuá or abelha-cachorro . The species name means "spiny feet" in Latin.-Habits:...

 does not interbreed and is known to kill or chase Africanized bees.

Misconceptions


The sting of the Africanized Honey Bee is no more potent than a garden variety honey bee, and they have a similar appearance. What makes Africanized honey bees more dangerous is that they are more easily provoked, quick to swarm, attack in greater numbers, and pursue their victims for greater distances. An Africanized bee colony can remain agitated longer and may attack up to a quarter of a mile away from the hive.

Queen management in African bee areas


In Mexico, where African bees are well established, pollination beekeepers have found that a purchased and pre-bred non-African queen may be used to locally create a first generation of virgin queens that are then bred in an uncontrolled fashion with the local wild African drones. These first generation African queens produce worker bees that are manageable, not exhibiting the intense and massive defense reactions of subsequent generations. This offers a relatively economical method of safe local beekeeping conditions that would otherwise quickly lead to hazardous conditions.

Impact on existing apiculture


In areas of suitable temperate climate, the survival traits of African queens and colonies outperform western honey bee colonies. This competitive edge leads to the dominance of African traits.
In Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, the African hybrids are known as Assassin
Assassination
To carry out an assassination is "to murder by a sudden and/or secret attack, often for political reasons." Alternatively, assassination may be defined as "the act of deliberately killing someone, especially a public figure, usually for hire or for political reasons."An assassination may be...

 Bees
, for their habit of taking over an existing hive of European bees; this habit is most evident when the hive being attacked has a weakened queen, so not all hives are equally vulnerable, and overall rates of hive usurpation can reach 20%.

Gentle African bees


Not all African hives show overly defensive behavior; some colonies are quiet, which gives a beginning point for beekeepers to breed a gentler stock. This has been done in Brazil, where bee incidents are much less common than they were during the first wave of the African bees' colonization. Now that the African bee has been "re-domesticated", it is considered the bee of choice for beekeeping in Brazil.

Further reading

  • Collet, T., Ferreira, K.M., Arias, M.C., Soares, A.E.E. and Del Lama, M.A. (2006). Genetic structure of African honeybee populations (Apis mellifera L.) from Brazil and Uruguay viewed through mitochondrial DNA COI–COII patterns. Heredity 97, 329–335. doi:10.1038/sj.hdy.6800875
  • Smith, D.R., Taylor, O.R., Brown, W.M. (1989). Neotropical African honey bees have African mitochondrial DNA. Nature 339: 213–215.

External links