Japanese honeybees surround a giant hornet. Image courtesy of Masato Ono, Tamagawa University
Can nature get any stranger? Japanese honeybees kill giant hornets by cooking them with their brains.
(BBC)- Japanese honeybees' response to a hive-invading giant hornet is efficient and dramatic; they form a "bee ball" around it, serving to cook and asphyxiate it.Now, researchers in Japan have measured the brain activity of honeybees when they form this killer ball.
One highly active area of the bees' brains, they believe, allows them to generate the constant heat which is deadly for the hornet.
The team published their findings in the open-access journal, PLoS One.
Prof Takeo Kubo from the University of Tokyo explained that "higher centres" of the bee's brain, known as the mushroom bodies, were more active in the brains of Japanese honeybees when they were a part of the "hot defensive bee ball".
To find this out, the team lured the bees to form their ball by attaching a hornet to the end of a wire and inserting the predator into the hive.
This simulated invasion caused the bees to swarm around the hornet. The researchers then plucked a few of the bees from the ball and measured, throughout each of their tiny brains, the relative amount of a chemical that is known to be a "marker" of brain activity.
"We found that similar [brain] activity is evoked when the Japanese honeybees are simply exposed to high temperature (46C) in the laboratory," the researcher told BBC Nature. Keep on reading...