Why are killer bees so angry? Study finds insects' aggression comes from genetics of European insects which mixed with African honey bees

  • Killer bees get their aggression from Western European bee genetics 
  • Researchers measured the defense response of 116 colonies with these bees
  • They found that the most defensive were related to South African honey bees
  • Genomes that influenced aggression were linked to those from Western Europe

Killer bees are known to chase people when agitated and experts have now found the root of this insect’s aggression.

A new study into the African hybrid honey bee reveals it was the mixing of European genetics that led to this invasive species’ hostility.

Researcher first bred South African honey bees with those in Europe during the 1950s with the hopes of created a better subtropical version, which escaped and mated with the local bees – bringing the dangerous insects to the Americas.

The team measured the defense response of 116 Brazilian colonies and found the most defensive were related to South African honey bees, except the genomes that influenced aggression were linked to those from Western Europe.

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Killer bees are known to chase people when agitated and experts have now found the root of this insect¿s aggression. A new study into the African hybrid honey bee reveals it was the mixing of European genetics that led to this invasive species¿ hostility

Killer bees are known to chase people when agitated and experts have now found the root of this insect’s aggression. A new study into the African hybrid honey bee reveals it was the mixing of European genetics that led to this invasive species’ hostility

The findings were collected by teams at York University and Purdue University, which set out to understand why this strain of honey bee is known for its aggression.

Amro Zayed, associate professor at York University, said: ‘The resulting bees were highly invasive and aggressive, much more than the European honey bees used by North and South American beekeepers at the time.’

‘The genetics causing this hyper defensiveness were not well known, but the prevailing wisdom was that killer bees are aggressive because South African bees are aggressive.’

When the bees escaped their cages in Brazil, they began to spread around South and Central America and by 1990, the insects had made their way up to the southern parts of the US.

Now, the African hybrid honey bees (AHB) have replaced the honey bees that came from Europe in Brazil and are the most common of its kind in Northern Argentina and the southern US.

To investigate the roots of AHB, the team study the defense response of 116 Brazilian AHB colonies using the Suede Ball test.

During this test, a ball was swung at the entrance of the colony as if it was an intruder.

Researcher first bred South African honey bees with those in Europe during the 1950s with the hopes of created a better subtropical version, which escaped and mated with the local bees ¿ bringing the dangerous insects to the Americas

Researcher first bred South African honey bees with those in Europe during the 1950s with the hopes of created a better subtropical version, which escaped and mated with the local bees – bringing the dangerous insects to the Americas

The team then examined the ball to see how much of it was destroyed to determine the colony’s defense response.

Brock Harpur, an assistant professor at Purdue University, said ‘We sequenced the genomes of the most aggressive colonies, which would sting the ball 90 times or more per minute, and the least aggressive colonies.’

‘We then compared the genomes of the most and least aggressive colonies to identify mutations that associate with these differences in behavior.’

The most defensive colonies were found to be more related to the South African insects, but after sequencing the genomes the team found the most aggressive bees came from Western Europe.

How do honeybees make a queen?

Queen bee brood cell is pictured above

Queen bee brood cell is pictured above

Honeybees make a queen by treating a normal youngster in a unique way, causing it to develop into a queen rather than a worker.

They start by building a special, larger cell, and filling it with a substance called 'royal jelly'.

This is a combination of water, sugars and proteins that appears milky in colour, secreted from glands in the heads of worker bees.

A youngster is then plucked from its cell and placed into the unique cell with the royal jelly, which it consumes.

To aide its development, a study published in Science Advances in 2015 suggested, it is also denied pollen and honey to aide its development, which is fed to normal workers.

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