“ Coyne’s chapter on “The Engine of Evolution” begins with a splendidly macabre example. Giant Japanese hornets raid the nests of honeybees to feed their larvae. A single hornet scout discovers a beehive and marks it “for doom” with a sort of chemical black spot. “Alerted by the mark, the scout’s nestmates descend on the spot, a group of twenty or thirty hornets arrayed against a colony of up to 30,000 honeybees. But it’s no contest. Wading into the hive with jaws slashing, the hornets decapitate the bees one by one. With each hornet making heads roll at a rate of forty per minute, the battle is over in a few hours: every bee is dead, and body parts litter the hive. Then the hornets stock their larder.” Coyne’s purpose in telling the story is to contrast the terrible fate of European bees, introduced into Japan, with native Japanese bees that have had time to evolve a defence. “And their defense is stunning – another marvel of adaptive behavior. When the hornet scout first arrives at the hive, the honeybees near the entrance rush into the hive, calling nestmates to arms while luring the hornet inside. In the meantime, hundreds of worker bees assemble inside the entrance. Once the hornet is inside, it is mobbed and covered by a tight ball of bees. Vibrating their abdomens, the bees quickly raise the temperature inside the ball to about 117 degrees Fahrenheit. In twenty minutes the hornet scout is cooked to death, and – usually – the nest is saved.
—
Stunning bee vs hornet defence
