Monday, February 1, 2010

Amazing Nature: Defending Against the Japanese Giant Hornet

The Japanese giant hornet is a fearsome predator. At nearly 2 inches long and built like an insect body builder, it is a force to be reckoned with. Let's put it this way: yellow jacket:Japanese giant hornet::Hugh Jackman:Andre the Giant. It is also a picky eater and will kill thousands of bees just so it can eat the tastiest bits of each bee. In fact, it is the bane of beekeepers in Japan. A coordinated attack of 2 dozen or so hornets will descend on a hive of European honey bees and destroy it in a matter of hours. The bee stings can't penetrate the hornet's armor and the hornets are quite capable of simply biting the bees in half. When the battle is over, the hornets take some of the honey and whatever tasty bits they feel like and go home. The hive usually doesn't recover.

For some reason, though, this isn't really a problem for the native honey bees. This is because the native honey bees have evolved an ingenious defense. They know two crucial facts about how the hornets opperate: 1) the raiding party is always preceeded by a scout that returns to the hornet colony with information about the location of the hive and 2) the hornets die of thermal death at 115 degrees F, while honey bees can survive to 118 degrees. So when the scout shows up looking for a likely target, hundreds of bees pounce on the intruder and hold it down. While they are doing this, they frantically vibrate their wings, generating heat. The heat in the pile builds up to 117 degrees or so, killing the hornet. The bees then stumble off to cool down, having saved the colony.


  1. Most excellent information but I would be even more interested in knowing how the the native honey bees developed this tactic.

  2. As would I, Bill. Evolution is an amazing thing, but it is hard to say where the bee got its trick. Probably some random mutation in there somewhere. I have been planning on doing a post on Biomimicry one of these days. I have been thinking for years about it and have only come up with one piece of technology that we developed that nature hasn't. I'm drawing a blank on what it is right now, though. Anyway, there is a great talk on about it. As for the bees, perhaps we can cross European bees with Asian ones to produce favorable results. Then again, it may produce something akin to killer bees again...

  3. You surely mean 115 degrees F, not C.