Six degrees from being overdone

It used to be thought that bees clustered around their enemies to sting them to death. But they can raise the temperature at the core of the cluster and cook 'em instead.

I've seen a hornet baked to death by my bees, but how come the bees don't cook themselves? Chinese researchers have been on the job:

To check the bees' and wasps' tolerance for heat, researchers then 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 heat to 50.7°C and the European bees made it to 51.8°C.

The native Asian bees, ancient adversaries of the wasps, mobilized half again as many defenders into a heat ball as the European bees did, the researchers report. Furthermore, Asian bees not mobbing the wasp were more likely to take shelter during an attack than bystander European bees were.

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.