Bees Defend Hive From Hornest With Heatballing Defense
Posted on October 5, 2005
If you have seen the 30 hornets vs. 30,000 bees video then you know the devastation a few hornets can cause a hive of bees. Fortunately, there a few honeybee species that defend themselves with a technique called heatballling where lots of bees surround a hornet raising the internal temperature and killing the wasp with their body heat. A Sciencenews.org article explains how the special honeybee defense works.
However, a few honeybee species can defend themselves by surrounding an invader. Researchers used to think that the few-dozen bees were trying to sting the wasp, says Seeley. Thermal cameras, however, revealed the balls' soaring heat.At least some bees can defend their nests. It still takes a great deal of bees and effort to kill a single invader.To see what margin of safety the bees have, Tan and his research colleagues presented tethered wasps to six colonies each of native Asian bees and European bees. 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 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.