Killer Bees: The Case That Shook America
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The Case That Shook America

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History of Killer Bees
in America


In the ‘60s, American media picked up a case that shook up countries all over the world: hybridization of two types of honeybee gave rise to an aggressive, unstoppable and lethal new organism. The killer bee had arrived.

This little insect appeared on the front cover of numerous famous magazines and newspapers during a long time and it even assumed the main role in some terror films (such as “The Swarm”, 1978). However, when did fiction surpass reality? What’s true in this story? Keep reading to get the answers.

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IN THE 50’S, THE IMPORTATION of European honeybees to America was a frequent practise. However, while beekeeping had good results in the USA, it didn’t seem to work in South America because honeybees from Europe didn’t adapted well to tropical climate. Thus, in 1956, the Brazilian scientist Warwick Kerr suggested to import African honeybees to Brazil instead of the European ones in an effort to increase honey production. Then, the unique main problem he needed to solve was the aggressive nature of this subspecies. The main objective of Dr. Kerr was to obtain a docile variety of bees that was also productive in tropical climates by artificial selection and cross-breeding of the African honey bee (A. m. scutellata) with various European honeybees.

The experimental bees rapidly formed new colonies and began to hybridize with both wild and domestic European honeybees, giving rise to the Africanised honeybees which were more aggressive and less productive than Dr. Kerr expected. These bees are currently located in almost all over the American continent. In the USA, they didn’t spread further north due to their tropical origins, so their range of distribution in North America is limited to the southern states of the USA

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African honeybees show some behavioural traits that make them
potentially more dangerous than their European relatives:

They are more aggressive, they accomplish massive attacks. Unlike European honeybees, which attack in groups of 10-20 individuals, African honeybees can do it in groups of 100-1000 individuals.

Even though reproductive biology and development are very similar among
honeybee races, African honeybees show some biological traits that lend
them adaptive advantages with respect the European ones.

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African honeybees show some biological traits that lend them
adaptive advantages with respect the European ones.

African and European Genes

Greater production of drones (male bees) by parthenogenesis. African colonies produce proportionally more male bees than European honeybees, which gather during the nuptial flight forming cloud of hundreds of individuals. So, the probability that a European queen mates with an African drone increases, and thus the probability to perpetuate African genes. Fast development. African colonies grow and spread faster than the European ones. Greater resistance to pathogens and parasites. For example, to Varroa destructor, to the small hive beetle Aethina tumida or even to bacteria of the genus Paenabacilis, which have finished with a lot of European honeybee populations in America.

The way all these traits express on hybrid bees varies depending on the proportion of African and European genes they present, which depends at the same time on the distance to the original spreading focus. So, the hybrid bees from the USA tend to be genetically closer to European honeybees and thus are less aggressive than the Africanised honeybees from other parts of America.

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Are they a public health concern?

There are reasons enough to consider both African and Africanised honeybees a public health concern.

However, the most stunning cases of massive attacks are not as frequent as
we could think. So, the real concern falls to risk groups (such as children, elderly,
sick or disabled people) and to domestic animals, which would have more difficult
to scape an attack.

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Despite the potential risk they pose, the situation is currently well managed because a great number of exhaustive studies have allowed to carry out different measures to control their populations (and even to take advantage of them). For many years, beekeepers have been breeding African and Africanised bees to produce honey and pollinize crops in Centre and South America, becoming one of the most important honey producers worldwide. To that effect, they apply special management measures, such as letting only one colony to develop inside the hive. 

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