AMAZING SCIENCE

A monthly serving of fascinating science

COOKING THE ENEMY

A Japanese wasp won’t survive

a trip into a packed beehive.

The honeybees that live there will

use their own body heat to kill.

Bee stingers can’t do anything

to pierce a wasp’s hard covering.

But bees can make the heat so high

that very soon the wasp will fry.

When Japanese honeybees want to get rid of an enemy, they cook it. Using the combined body heat of 500 buzzing bees, they quickly turn a large invader into a crispy critter. The honeybees, need this defense to protect themselves from attacks by arge, dangerous Japanese giant hornets. The hornets, actually wasps that feed on bees, normally depend on teamwork to attack and destroy their prey.

When a giant hornet finds a beehive, it marks the hive with a chemical attractant. The chemical acts like sign that says “good eats here.’ It draws dozens of other hornets to the nest. Then, the predators join together in a mass raid. Using large yellow mandibles or mouthparts, the nearly two-inch long invaders attack and crush the honeybees one by one. Giant hornets can mash around 40 bees a minute. At that pace, group of 30 hornets can destroy a colony of 30,000 honeybees in just 3 hours. When they finish, the hornets carry the dead bees home to their young.

European honeybees that live in Japan have no way to fight these aggressive predators. The bees’ stingers are useless against the thick, hard exoskeleton that covers the outside of a hornet. They can, however, kill with heat. Creating heat is actually something that bees do all the time, by shivering; much the way people do when they’re cold. When people shiver, they contract or tighten their muscles. Actively working muscles produce lots of heat. Bees get warm by contracting their powerful wing muscles, while holding their wings very still. By not flying around when they work their muscles, the bees turn all of their muscle energy into ‘bee heat’.

Japanese bees have turned this ‘bee heat’ into a powerful weapon. If they detect a hornet in the hive, the bees launch a counterattack. A mass of worker bees forms a ball around the invader. Then the bees begin to vibrate. As temperatures in the ball rise to a very hot 117oF, the hornet starts to fry. Meanwhile the bees, which can tolerate temperatures of 122oF, are not bothered at all. Eventually the hornet dies. The bees then simply push it out of the nest and go on about their business.