Africanized bee
The Africanized bee, also known as the Africanized honey bee and colloquially as the "killer bee", is a hybrid of the western honey bee, produced originally by crossbreeding of the African honey bee with various European honey bee subspecies such as the Italian honey bee and the Iberian honey bee.
The African honey bee was first introduced to Brazil in 1956 in an effort to increase honey production, but 26 swarms escaped quarantine in 1957. Since then, the hybrid has spread throughout South America and arrived in North America in 1985. Hives were found in south Texas in the United States in 1990.
Africanized honey bees are typically much more defensive, react to disturbances faster, and chase people farther than other varieties of honey bees, up to. They have killed some 1,000 humans, with victims receiving 10 times more stings than from European honey bees. They have also killed horses and other animals.
History
There are 29 recognized subspecies of Apis mellifera based largely on geographic variations. All subspecies are cross-fertile. Geographic isolation led to numerous local adaptations. These adaptations include brood cycles synchronized with the bloom period of local flora, forming a winter cluster in colder climates, migratory swarming in Africa, enhanced foraging behavior in desert areas, and numerous other inherited traits.The Africanized honey bees in the Western Hemisphere are descended from hives operated by biologist Warwick E. Kerr, who had interbred honey bees from Europe and southern Africa. Kerr was attempting to breed a strain of bees that would produce more honey in tropical conditions than the European strain of honey bee then in use throughout North, Central and South America. The hives containing this particular African subspecies were housed at an apiary near Rio Claro, São Paulo, in the southeast of Brazil, and were noted to be especially defensive. These hives had been fitted with special excluder screens to prevent the larger queen bees and drones from getting out and mating with the local population of European bees. According to Kerr, in October 1957 a visiting beekeeper, noticing that the queen excluders were interfering with the worker bees' movement, removed them, resulting in the accidental release of 26 Tanganyikan swarms of A. m. scutellata. Following this accidental release, the Africanized honey bee swarms spread out and crossbred with local European honey bee colonies.
The descendants of these colonies have since spread throughout the Americas, moving through the Amazon basin in the 1970s, crossing into Central America in 1982, and reaching Mexico in 1985. Because their movement through these regions was rapid and largely unassisted by humans, Africanized honey bees have earned the reputation of being a notorious invasive species. The prospect of killer bees arriving in the United States caused a media sensation in the late 1970s, inspired several horror movies, and sparked debate about the wisdom of humans altering entire ecosystems.
The first Africanized honey bees in the U.S. were discovered in 1985 at an oil field in the San Joaquin Valley of California. Bee experts theorized the colony had not traveled overland but instead "arrived hidden in a load of oil-drilling pipe shipped from South America." The first permanent colonies arrived in Texas from Mexico in 1990. In the Tucson region of Arizona, a study of trapped swarms in 1994 found that only 15 percent had been Africanized; this number had grown to 90 percent by 1997.
Characteristics
Though Africanized honey bees display certain behavioral traits that make them less than desirable for commercial beekeeping, excessive defensiveness and swarming foremost, they have now become the dominant type of honey bee for beekeeping in Central and South America due to their genetic dominance as well as ability to out-compete their European counterpart, with some beekeepers asserting that they are superior honey producers and pollinators.Africanized honey bees, as opposed to other Western bee types:
- Tend to swarm more frequently and go farther than other types of honey bees.
- Are more likely to migrate as part of a seasonal response to lowered food supply.
- Are more likely to "abscond"—the entire colony leaves the hive and relocates—in response to stress.
- Have greater defensiveness when in a resting swarm, compared to other honey bee types.
- Live more often in ground cavities than the European types.
- Guard the hive aggressively, with a larger alarm zone around the hive.
- Have a higher proportion of "guard" bees within the hive.
- Deploy in greater numbers for defense and pursue perceived threats over much longer distances from the hive.
- Cannot survive extended periods of forage deprivation, preventing introduction into areas with harsh winters or extremely dry late summers.
- Live in dramatically higher population densities.
North American distribution
On 11 September 2007, Commissioner Bob Odom of the Louisiana Department of Agriculture and Forestry said that Africanized honey bees had established themselves in the New Orleans area. In February 2009, Africanized honey bees were found in southern Utah. The bees had spread into eight counties in Utah, as far north as Grand and Emery Counties by May 2017.
In October 2010, a 73-year-old man was killed by a swarm of Africanized honey bees while clearing brush on his south Georgia property, as determined by Georgia's Department of Agriculture. In 2012, Tennessee state officials reported that a colony was found for the first time in a beekeeper's colony in Monroe County in the eastern part of the state. In June 2013, 62-year-old Larry Goodwin of Moody, Texas, was killed by a swarm of Africanized honey bees.
In May 2014, Colorado State University confirmed that bees from a swarm which had aggressively attacked an orchardist near Palisade, in west-central Colorado, were from an Africanized honey bee hive. The hive was subsequently destroyed.
In tropical climates they effectively out-compete European honey bees and, at their peak rate of expansion, they spread north at almost two kilometers 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, but various national and international agricultural departments could not prevent the bees' expansion. Current knowledge of the genetics of these bees suggests that such a strategy, had it been tried, would not have been successful.
As the Africanized honey bee migrates further north, colonies continue to interbreed with European honey bees. In a study conducted in Arizona in 2004 it was observed that swarms of Africanized honey bees could take over weakened European honey bee hives by invading the hive, then killing the European queen and establishing their own queen. There are now relatively stable geographic zones in which either Africanized honey bees dominate, a mix of Africanized and European honey bees is present, or only non-Africanized honey bees are found, as in the southern portions of South America or northern North America.
African honey bees abscond 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 not enough stores to survive the winter. Thus Africanized honey bees are expected to be a hazard mostly in the southern states of the United States, reaching as far north as the Chesapeake Bay in the east. The cold-weather limits of the Africanized honey bee have driven some professional bee breeders from Southern California into the harsher wintering locales of the northern Sierra Nevada and southern Cascade Range. This is a more difficult area to prepare bees for early pollination placement in, such as is required for the production of almonds. The reduced available winter forage in northern California means that bees must be fed for early spring buildup.
The arrival of the Africanized honey bee in Central America is threatening the traditional craft of keeping Melipona stingless bees in log gums, although they do not interbreed or directly compete with each other. The honey production from an individual hive of Africanized honey bees can be as high as. This value exceeds the much smaller of the various Melipona stingless bee species. Thus economic pressures are forcing beekeepers to switch from the traditional stingless bees to the new reality of the Africanized honey bee. Whether this will lead to the extinction of the former is unknown, but they are well adapted to exist in the wild, and there are a number of indigenous plants that the Africanized honey bees do not visit, so the fate of the Melipona bees remains to be seen.
File:Creation-Via-Pollination.jpg|thumb|250px|right|Gathering pollen, Engelmann's prickly pear, Mojave Desert