Africanized honey bee
Africanized American honey bees are honey bees in the tropical and subtropical zones of the American double continent. The hybrids of Apis mellifera arise again and again by the mixing (crossing) imkerlich cultivated bee colonies occasionally added queens of European descent and drones dominant, wild bee populations of African descent. Both this hybrid and just the wild bees are often referred to as killer bees because of their aggressiveness .
The honey bee was not native to either North , Central and South America before the arrival of Europeans. Nevertheless, the indigenous people, z. B. the Maya , honey won. This came from stingless bees (Meliponini), which produce significantly less honey than honey bees. In the course of colonization , European honey bees, mostly German or Italian breeds , were introduced, but they did not cope well with the tropical climate. For this reason, attempts were made in the 1950s to increase productivity by crossing African honey bees.
history
The beekeeper Warwick Kerr traveled to Africa as part of his bee research in 1955 and therefore, at the request of the Brazilian Ministry of Agriculture, brought a total of 120 African queen bees of the subspecies Apis mellifera scutellata from Johannesburg to Rio Claro in Brazil , which is about 22 ° south latitude, in the following year Crossing with the local bees of European origin to obtain more efficient honey bees. In 1957, through negligence, 26 flocks with African queens escaped. Complicity in this disaster was a previously not right instruierter employee who had the grill of the hive from which the queens on the trip are to prevent would. Contrary to previous experience that honey bees could hardly establish themselves in the wild in the tropical regions of Brazil, the African honey bees proved to be able to cope well with the tropical climate. With densities of up to 100, albeit small, colonies per square kilometer, they spread rapidly across the entire continent at a speed of 300 to 500 km per year .
In doing so, they repeatedly crossed with the existing bees kept by beekeepers . Amazingly, this did not lead to the bees becoming more European, but rather the African parts completely displaced the European parts, as the queens with African genes hatch about a day earlier and thus have a greater chance of taking over the devoured colony. Among other differences, these African or Africanized bees are also much more aggressive towards humans than European bees, which also earned them the name "killer bees", since a very large number of bee stings can be fatal. It was only in the more moderate latitudes of South America, around the height of Buenos Aires , that a transition zone formed in which the bees became more and more European until they finally no longer displace the European honey bees there in cooler areas, around the height of the Bahía Blanca could. In less than 40 years they have arrived in the south of the USA , where they will probably only be inferior to the traditional European bees in the northern latitudes. In Europe, these Africanized bees should not have a chance to spread because the winters are too cold.
The difference between “killer bees” and other bee breeds is that when threatened, almost all of the bees in the colony attack, instead of the usual small number of animals. The "killer bees" also persistently pursue their victims. This makes it very easy to reach the threshold of around 500 stings at which a child can be killed, in adults it becomes critical from around 1,000 stings.
According to his own statements, Kerr was able to curb the aggressiveness in 1965 by crossing harmless species, but at the same time he emphasizes that it was the beekeepers who did not want more peaceful bees, since the Africanized honey bees per colony have 60 to 80 kilograms of honey Year, which corresponds to four times the production of the old species. In 2005, Kerr admitted that in the past, an average of 25 people were killed by bees in Brazil. After the bee breeding with the "Africanized bee", the number rose to 195. However, the number is said to have decreased somewhat due to the crossing of less aggressive animals. However, the bees also settle in the wild, where the aggressive genes are not switched off by breeding.
When asked if he would do the crossing again, Kerr replied that the researchers had to go to all bee conventions at the time and explain to people that they should put more emphasis on protective clothing (especially gloves); in the case of further breeding, the most aggressive lines could finally be sorted out. And it should not be forgotten that Brazil ranks third in the world for honey production thanks to its breeds, which is an important innovation for the poor northeast of Brazil. However, he then confirmed that he would no longer carry out breeding in this form today.
Kerr assumes that the problem that arises from breeding, similar to that of shark accidents , is being exaggerated: “In Brazil we have almost 200 deaths every year from our bees. There are five times as many road deaths on a certain street in São Paulo . "
Beekeeping use
The beekeepers of South America have, of necessity, but also for economic reasons, adjusted to the Africanized honeybees. It brings very good honey yields , not least due to the genetic make-up of the Italian bee . Again and again, queens of this highly populous bee breed are used (insisted) into the colonies , which have then mated (crossed) with drones of the wild breed in the second generation at the latest .
To make it easier to process the bee colonies, certain times of the day are used when a particularly large number of the defensive foragers are out and about. This is mainly the early morning. In contrast to most other bee breeds kept by beekeepers, complete protective clothing (veil, suit, gloves) is still required.
Possible ecological influences
The naturalization and rapid spread of the Africanized honeybees in America soon aroused fears that, in addition to the direct effects on humans, there could also be long-term ecological damage, since America did not have an autochthonous honeybee species. A strong influence on the natural pollinator community has been speculated in many publications. In particular, a displacement of the American stingless bees was expected. According to recent studies, such consequences have not materialized: in the choice of nesting site and in the choice of flowers, the species are too specific in their demands for displacement to occur. In direct interactions on the flowers, even the American stingless Meliponini tend to be more aggressive and competitive.
See also
- The deadly bees with a list of horror films on the subject
- In the satirical documentary Bowling for Columbine by the American director Michael Moore , the American reporting on the topic of "Africanized killer bees" is listed as an example of mass hysteria .
Web links
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- ↑ MK O'Malley, JD Ellis, CM Zettel Nalen: Differences Between European and African Honey Bees , University of Florida.
- ^ Robin FA Moritz, Stephan Härtel, Peter Neumann (2005): Global invasions of the western honeybee (Apis mellifera) and the consequences for biodiversity . Ecoscience 12 (3): 289-301. doi : 10.2980 / i1195-6860-12-3-289.1