Honeybees of the Cyprian strain can kill an attacking hornet by ganging up and smothering it.
That tactic is new to scientists, says Alexandros Papachristoforou of Aristotle University of Thessaloniki in Greece, although it resembles an Asian honeybee species' so-called heat-balling defense. When using that maneuver, the Asian bees cluster around a marauding hornet of another species and cook it to death with their body heat.
With Cyprian bees and the hornet Vespa orientalis, however, "we noticed some things that didn't match," says Papachristoforou. Cyprian bee balls warm to only 44°C. Tests show that a hornet kept at that temperature takes almost 2.5 hours to die, but Cyprian bees dispose of their foe in just 1 hour.
The researchers observed that Cyprian bees first surround the abdomen of the hornet, where its breathing holes are. Unlike most other insects, a hornet breathes by abdominal contractions.