This is pretty fascinating

[Mklangelo]

I found this in a PDF article while doing some research on the place I'm ordering a Queen from.  I though it would be of interest.


According to a study in China, honeybees defend their colonies against giant killer wasps in a very unusual way with body heat. The bees mob the invader wasp, mass around its body, then vibrate their wing muscles to generate heat â€" and not just a little heat, but enough to cook the wasp!
There are two species of honeybees living in China, the native Apis cerana and introduced European honeybee, Apis mellifera. Both species trap the wasp once it has entered the colony and then engulf her in a living ball of bees. The bees then begin to slowly raise the temperature until the wasp dies from hyperthermia. However, they come within 5°C of killing or cooking themselves during the process, which is a small margin when you think about it. There are no little thermometers inside a beehive, hence they must be aware of
the rising temperatures themselves before they reach a critical threshold. Tan Ken of Yunnan Agricultural University in Kunming, China, reports that the native bees have this heat-balling ability where the European bees don't. This makes sense if you think about it. The Asian bees have long shared their range with this colony invader Vespa velutina, but European bees have only became widespread in Asia about 50 years ago and have had less time to adapt to the wasp.
These attacker wasps are "gigantic," says Thomas Seeley of Cornell University, who studies bee behavior. Of all social insects, this species has the largest workers, with wingspans that can stretch 5 centimeters. They build large papery nests similar to their North American cousins the hornets. The wasps specialize in breaking into other social-insect nests and carrying off larvae as food for their young. “I've seen a single wasp overwhelm a colony of 6,000 bees” that doesn't make the “heat balls,” says Seeley. The invader wasp will stand at the nest’s entrance and as one guard bee after another comes out to defend its home the wasp cuts them into pieces then waits for the next to appear. When all the defenders are dead, “the wasps strip-mine out the larvae,” he reports.
Researchers used to think that the few dozen bees surrounding an invader were just trying to sting the wasp, but recently it was revealed, with the help of thermal cameras, that it is the balls’ soaring heat that actually kills the wasp. To test the bees’ margin of safety, Tan and his research colleagues presented tethered wasps to six Asian and European colonies. At each nest, worker bees engulfed the wasp immediately. Within 5 minutes, the center of a typical bee ball had reached 45°C. To check the bees’ and wasps’ tolerance for heat, researchers caged each of the species in incubators and systematically cranked up the temperature. The wasps died at 45.7°C, but the Asian honeybees survived to temperatures reaching 50.7°C and the European bees to 51.8°C. Researchers reported the native Asian bees, ancient adversaries of these killer wasps, mobilized half as many defenders as the Europeans. Furthermore, Asian bees not mobbing the wasp were more likely to take shelter during an attack than were bystander European bees. Heat balling is the flip side of bees nursing larvae in a nest, says Seeley. To keep the youngsters at the right temperature in cool weather, honeybees space themselves around the nursery and shiver their powerful flight muscles to generate heat. Seeley notes, however, that the nursemaids don't raise the temperature above 36°C, so the brood stays safe.

[Moonshae]

There is a video of this on youtube:

http://youtube.com/watch?v=dp72gXkYJIw

Hornets vs European honey bees:

http://youtube.com/watch?v=iEVegllkz5Y