The species is notorious for aggression. And now we know where this passionate behavior comes from.
The Africanized honey bee is often referred to as ‘killer bee’. And he has that nickname for a reason. The bugs have a fairly negative reputation because they can be very aggressive. An angry swarm has already killed several people. But why is the killer bee so aggressive? Investigators figured it out.
About the Africanized Honeybee
The Africanized honeybee is actually the result of a genetic experiment that went wrong. Brazilian researchers imported a South African subspecies and cultivated them with European-derived honey bees in the 1950s. The idea was to develop a better subtropical variant. But then some accidentally escaped. And these bees then unexpectedly escaped horses with the local bees.
It resulted in a new species that no one was really waiting for. “The resulting bees were invasive and very aggressive,” explains researcher Amro Zayed. “Much worse than the European honey bees that were used by North and South American beekeepers at the time.” Where this aggressiveness came from was a mystery. “The genetics that caused this hyperagression were not well known,” Zayed continues. “But the prevailing theory was that the Africanized honey bee was aggressive because the South African bees were.”More about aggression in the ‘killer bee’
Aggression in the species means that honey bees from Africa attack more quickly. Moreover, they immediately attack in larger flocks. The poison is no more powerful than that of other bee species. However, someone who is attacked will be stung by the ‘killer bee’ more often. And that can be fatal, especially when someone is also allergic.
The new colonies fanned out at a rapid pace. For example, the Africanized honey bee spread not only across Brazil, but also across South America, Central America and, in 1990, the southern states of the United States. Today, they have completely replaced the European derived honey bee in Brazil. In addition, they have become the most common honey bee from Northern Argentina to the southern United States. This success has to do with several factors. First of all, they come from a tropical area. It means that in these climates they thrive better than their European counterparts. In tropical areas where both species live side by side, the Africanized bee can easily compete with European honey bees.
The genetically modified bee is now found in many places, where it sometimes ends up in the water of unsuspecting people. In the United States, for example, Africanized honey bees are responsible for one to two deaths per year. To determine where the hyperagression of the Africanized honey bee comes from, the researchers decided to conduct an experiment. They collected 116 Brazilian Africanized honey bee colonies and swung a black leather ball a few minutes in front of the entrance to the hive to provoke a response.
Many bees flew aggressively at the ball and immediately stung. “Some colonies hit the ball 90 or more times per minute,” said researcher Samir Kadri. “We decided to sequence the genome of the most aggressive colonies. We then compared the genomes of the most and least aggressive colonies to discover mutations related to their different behaviors. ”
The researchers found that the most defensive colonies were more akin to South African honey bees. But after sequencing the genomes, the team discovered that the most aggressive specimens were related to Western European bees. It means that the aggressiveness in Africanized honeybee was partly brought about by a European ancestor. Although it is mainly the poor mix that counts. “The mixing of the two honey bee subspecies has ultimately led to the hyperagression seen in this invasive species,” said Zayed.
Although the findings from the study provide an answer to a pressing question, the researchers have not yet let go of the subject. Follow-up research has to show how exactly the DNA of these two subspecies influences the aggressive immune response.