12.02.12

If such a creature is frightening to humans, imagine what it would look like to a honeybee. Scientists observing wild colonies of the Japanese honeybee, Apis cerana japonica, have long known that the colonies are vulnerable to attacks from the giant hornets. Usually a single hornet shows up first to scout the area. It kills a few bees and brings them back to the hive to feed its young. After a few of these trips, the hornet tags the hive by smearing it with pheromones, signaling that it is time for an attack.

A gang of about thirty hornets descend on the hive, and within a few hours these monstrous creatures massacre as many as thirty thousand of the small honeybees, ripping off their heads and tossing their bodies on the ground. Once they've killed the bees, the hornets occupy the empty hive for about ten days, robbing it of its honey and stealing the bee larvae to feed their own children.

Recently, Masato Ono and his colleagues at Tamagawa University discovered that the Japanese honeybees had devised an extraordinarily clever way of attacking back. The first time a solitary hornet approaches the hive, worker bees retreat inside, luring the hornet to the entrance. Then an army of over five hundred honeybees surround the hornet, beating their wings furiously and raising the surrounding temperature to 116 degrees—just hot enough to kill the hornet.

This is a dangerous procedure for the honeybees: if the swarm gets just a few degrees hotter, it will kill them as well. In fact, some worker bees do die in the struggle, but the swarm pushes them out of the way and carries on until the hornet is dead. It can take twenty minutes for the honeybees to bake their enemy to death. While it is not unusual for insects to mount a group defense against an enemy, this is the only known case of using body heat alone to defeat an attacker.

(amy stewart, from wicked bugs)