THE VINE MARCH 5, 2010
Since it's Friday afternoon, why not some wild nature facts? This tidbit about Asian giant hornets, courtesy of University of Chicago biologist (and frequent TNR contributor) Jerry Coyne's book Why Evolution Is True, is easily the best hornet anecdote I've ever come across:
One of the marvels of evolution is the Asian giant hornet, a predatory wasp especially common in Japan. It's the world's largest hornet—as long as your thumb—with a two-inch body ornamented with menacing orange and black stripes. It's armed not only with fearsome jaws to clasp and kill its insect prey, but also a quarter-inch stinger. ...
One of the hornet's prime victims is the introduced European honeybee. The raid on a honeybee nest involves a merciless mass slaughter that has few parallels in nature. It starts when a lone hornet scout finds a nest. With its abdomen, the scout marks the nest for doom, placing a drop of pheromone near the entrance of the bee colony. Alerted by the mark, the scout's nestmates descend upon the spot, a group of twenty or thirty hornets arrayed against a colony of up to thirty thousand 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 bee 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. Over the next week, they systematically ravage the nest, eating honey and carrying the helpless bee grubs back to their own nests, where they are promptly deposited into the gaping mouths of the hornets' own ravenous offspring. ...
But there are bees that can fight off the giant hornet: honeybees that are native to Japan. And their defense is stunning—another marvel of adaptive behavior. When the hornet scout first arrives at their hive, the honeybees near the entrance rush into the hive, calling nestmates to arms and 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. Bees can survive this temperature, but the hornet can not. In twenty minutes the hornet scout is cooked to death, and—usually—the nest is saved.
There's video, too, though it can get a bit graphic.