Africanized bee: Encyclopedia - Africanized bee

Africanized bee

Africanized bees, also known as killer bees, are hybrids of the African honeybee, Apis mellifera adansonii (or by other reports A. m. scutellata), with various European honeybees such as the Italian bee Apis mellifera ligustica. They have come to be the preferred type of bee for beekeeping in tropical areas of South America and in Central America because of improved productivity.

In most areas the Africanize hybrid is initially feared, because it tends to retain certain behavioral traits from its African ancestors that make it seem less desirable for domestic beekeeping, specifically (as compared with the European types):

1. To have a tendency to frequently swarm.
2. To be more likely to abscond as part of a seasonal migratory pattern in response to lowered food supply.
3. To have greater defensiveness when in a resting swarm
4. To live more often in ground cavities than the European types.
5. To be highly defensive in guarding the hive, with a larger alarm zone around the hive.
6. To have a high proportion of "soldier" bees within the hive prepared for exit and defense.
7. To recruit additional bees from within the hive for defense.
8. To pursue and sting perceived threats in far greater numbers and over much longer distances.

While the African source bees are significantly smaller than the European bees, the hybrids are similar to the European bees in size, with only a slightly shorter wing that may be determined only by examination of a large sample. They are descended from 26 Tanzanian queen bees accidentally released in 1957 in Southern Brazil from hives operated by biologist Warwick E. Kerr, who had interbred European honeybees and bees from southern Africa. Hives containing these particular queens were noted to be especially defensive. Kerr was attempting to breed a strain of bees that would be better adapted to tropical conditions (i.e., more productive) than the European bee used in North America and southern South America.

Africanized bee - Aggressiveness

Africanized bees are characterized by their aggressiveness in establishing new hives and in their vigorous defensive behavior, attacking perceived threats to their hive, including people. Over the decades, hundreds of deaths in the Americas have been attributed to Africanized bees, many deaths resulting from multiple bee stings. This defensiveness has earned them the nickname "killer bees", the aptness of which is debated. Allergic reactions to bee venom from European honeybees also kills people, and it is difficult to estimate how many more people may have died due to the presence of Africanized bees.

Most human incidents with Africanized bees occur within two or three years of its arrival and then subside. Beekeepers can help greatly in this process by culling the queens of mean strains and breeding gentler stock. Beekeepers keep Apis mellifera scutellata in South Africa using common beekeeping practices without excessive problems.

Africanized bee - Geographic spread

As of 2002, Africanized honeybees had spread from Brazil south to northern Argentina and north to South and Central America, México, Texas, Arizona, New Mexico, 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 indicate this species of bees has penetrated this barrier, or have come as a swarm aboard a ship. In June 2005, it was discovered that the bees had penetrated the border of Texas and had spread into Southwest Arkansas. In the summer of 2005, Africanized bees were discovered in six counties of Florida where they had apparently been present long enough to spread widely without detection.

At their peak rate of expansion, they spread north at a rate of almost two kilometers (about one mile) a day. In tropical climates they compete effectively against European bees. There have been many opportunities to slow the spread by introducing non-defensive relatives, particularly at the Isthmus of Panama, but various national and international agricultural departments proved themselves incapable of action, and remain so to this day.

Curiously, their arrival in Central America is a threat to the ancient art of keeping stingless bees, because of the orders of magnitude of increased production possible, causing beekeepers to switch.

Note though that beekeepers keep Apis mellifera scutellata in South Africa using common beekeeping practices without excessive problems.

Africanized bee - Geographic limits

Recent evidence suggests that Africanized honeybees are less able to survive a cold winter. This is seen in the southern limit of the spread of Africanized bees in eastern South America. There are now stable geographic zones in which Africanized bees dominate, a mix of Africanized and European bees are present, and in the southern reaches only non-Africanized bees are found. As the Africanized honeybee migrates further north through Mexico, colonies are interbreeding with European honeybees. This appears to be resulting in a dilution of the genetic contribution of the African stock and a gradual reduction of the aggressive behaviors. Thus Africanized bees are expected to be a hazard mostly in the Southern States of the United States. In California they have been seen on the Pacific Coast as far north as Santa Barbara and are expected to eventually occupy the San Francisco Bay Area. Within the Central Valley in 2004 Africanized bees were involved in an attack in Modesto, having previously (2003) been seen in Bakersfield. The cold weather limits of the Africanized bee have driven professional bee breeders from Southern California into the harsher wintering locals of the northern Sierra Nevada (US) and southern Cascade range. This is a more difficult area in which to prepare bees for early pollination placement, such as is required for the production of almonds as the reduced available forage means bees must be fed for early spring buildup.

Africanized bee - Difficulty in determination

The popular term 'Africanized 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, also present in the southeastern United States, that has the same morphology.

Africanized bee - Effects of selective breeding

Africanized bee - In the European Bee intentional selection

The chief difference between the European races or subspecies of bees kept by American beekeepers and the Africanized 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. Beekeepers have tended to eliminate the fierce strains as they did, and the entire race of bees has thus been gentled by selective breeding.

Africanized bee - In the African Bee natural selection

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. Thus the African bee has been naturally selected for ferocity.

Africanized bee - The Assassin Bee?

Africanized bee - The lore

In Brazil, the Afrucab bee and its hybrid are known as the Assassin Bee, for its supposed habits in taking over an existing colony of European bees. According to this lore, their queen waits outside while several worker bees infiltrate the hive by bringing in food, where they will then locate and kill the queen. The new queen will then enter and take over the hive.

Africanized bee - The danger to apiculture

It has been established that in a partially Africanized hive these aggressive bees can even "recruit" more gentle bees in attacks upon intruders. If true, this habit can make Africanized bees dangerous in areas where European bees are kept for agricultural purposes, since an existing queen may be replaced without the usual out-swarming or supersession, conditions more readily observable by the beekeeper.

Africanized bee - Genetic evidence

Evidence for the accuracy of this report can be found in the fact that of Africanized bees in Brazil, about one third have mitochondrial DNA indicating a female ancestor of African origin. If the Africanization was attributable only (or even mostly) to the well known superior breeding efficiency of Africanized (male) drones, such "mother" DNA would be much less prevalent. Although some bee species (such as the Cape Bee Apis mellifera capensis of South Africa) are known to be able to propagate additional females via egg laying female workers, this is not believed to occur in either A. m. adansonii or A. m. scutellata.

Africanized bee - Behavioral evidence

Apis mellifera scutellata is well known for sending from the hive numerous tiny swarms - a queen and only a few attendants. Such a small swarm should be incapable of starting a colony on its own, lacking enough workers for all the tasks required to support a queen and in particular incapable of beginning a new colony. For this behavior to have survived through natural selection it may be arguably inferred that it likely has some utility to the survival and propagation of the species. The supposed assassin behavior is not inconsistent with this argument and is actually reinforced by it.

Africanized bee - Gentle Africanized bees

Not all Africanized hives are defensive; some are quite gentle, 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 during the first wave of the Africanized bees' colonization. Now that the Africanized bee has been gentled, it is considered the bee of choice for beekeeping in Brazil. It is better adapted to the tropics and so is healthier and more industrious than European bees.

Africanized bee - Queen management in Africanized bee areas

In Mexico, where Africanized bees are well established, pollination beekeepers have found that a purchased and pre-bred non-Africanized 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 Africanized drones. These first generation Africanized queens produce worker bees that are manageable, not exhibiting the intense and massive defense reactions of subseqent generations. This offers a relatively economical method of safe local beekeeping conditions that would otherwise quickly lead to hazardous conditions.

Africanized bee - How to avoid bees

Africanized bee - Use caution with power mowers

Bees are sensitive to low frequency vibrations and so an engine driven lawn mower may elicit a defense response from a hive or swarm.

Africanized bee - Walk with care in clover and near picnic sites

Take care not to walk barefoot on lawns containing blooming clover, which attracts foraging bees. Meat eating wasps can be attracted to food scraps near a picnic site and usually forage close to the ground as they seek out downed insects such as dead and dying bees, especially near beehives.

Africanized bee - Avoid perfume cologne and scented cosmetics

Foraging bees will seek out floral scents. Such a bee will be harmless to you unless you swat at it, as it is only trying to find a flower. Yellowjackets can be much more aggressive, even to the point of biting.

Africanized bee - Beware of head-butting bees

Honeybees usually have a small number of sentry bees patrolling the perimeter of the hive's territory. In some if not most cases, these sentry bees will initially head butt (not sting) any animal that enters the hive's territory. If the animal continues closer to the hive, stinging will ensue.

If bees start head-butting you, use this behavior as a warning to retrace your steps and walk away from the hive. Choosing any other path could lead you deeper into the hive's territory.

Africanized bee - Wear light colors

Honeybees react to dark colors. Knowing this, beekeepers always wear white (or light colored) protective suits when working with bees during daylight. Bees have poor night vision and so beekeepers wear dark colors when collecting swarms after sunset. When traveling through areas with bees, wear light colors to avoid attracting bees. Bees are inactive at night and are unlikely to be encountered unless you bump into a resting swarm.

Africanized bee - Water meter chambers

While an occasional behaviour of European bees, African and Africanized bees are known to frequently nest in ground cavities. In suburban areas, a favored place is the in-ground concrete chamber that contains a water meter. The small lifting hole in the cover becomes the entrance to their hive. If the outside air temperature is over 60°F (15°C) you will probably see bees using this entrance if they are present, otherwise, use caution if you are in an area known to have Africanized bees.

Africanized bee - Open air hives

While all bees may build open air hives in mild climates, this is much more prevalent with Africanized bees (as well as certain "rafter bees" native to southeast Asia). African bees are also much more migratory and can move the colony to an entirely new location in pursuit of good foraging (leaving behind their combs at the old location, which may be reoccupied by other swarms in the appropriate season).

See also

• Africanized bee - a hybrid bee with characteristics unsuitable for beekeeping.
• Apiary - a yard where behives are kept
• Apitherapy - human therapy using bee venom
• Bee - a member of the family that includes ants, wasps, and termites
• Bee anatomy (mouth)
• Bee learning and communication
• Bee sting
• Bee venom therapy - also called apitherapy
• Beehive - a housing for cavity-dwelling bees that allows inspection and honey removal
• Beekeeping - bees are kept for their products (principally honey), and their utility in pollenating crops
• Beekeeping leading practices - newer techniques of beekeeping
• Brood (honeybee) - the egg, larval, and pupal form of the bee and the comb in which they develop
• Buckfast hybrid bee - a productive bee suitable for damp and cloudy climes.
• Characteristics of common wasps and bees
• Deseret - the beehive and its symbolism to the Church of Later-Day Saints (Mormons)
• Drone bee - the male bee
• Diseases of the honeybee
• Honeybee - bees particularly suitable for use in apiculture
• Honeybee life cycle - the physical stages in the development of a mature bee starting from the egg
• Laying worker bee - this worker will produce only drone bees
• Langstroth_hive - commonly seen in developed countries as stacks of white boxes at the edges of fields and orchards
• List of honeybee races
• Pesticide toxicity to bees
• Piping queen - queens will make audible sounds at certain times
• Stingless bees - Trigona and Melipona bees kept from ancient times in Central America and Australia
• Swarming - the means by which bee colonies propagate
• Supercedure - replacement of a reigning queen by her workers
• Queen bee - a single egg laying bee capable of producing workers, drones, and queens
• Top-bar hive - an alternative to the Langsthroth box hive, with some advantages for casual beekeeping
• Virgin queen - A queen that has not yet bred with drones
• Western honeybee European honeybees
• Worker bee - the many tasks performed by this class of bee during her short lifetime and her specialized single-use stinger

Adapted from the Wikipedia article "Africanized bee", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki