Scientists have discovered a new bizarre behavior in Asian honeybees. Called the Cyprian honeybees, this species of honeybees have adapted a rather an unexpected mob strategy in order to kill their nemesis, the Oriental hornet by smothering, causing them to asphyxiate.

Gérard Arnold of CNRS in Gif-sur-Yvette, France said “Here, for the first time we detail an amazing defense strategy, namely asphyxia-balling, by which Cyprian honeybees mob the hornet and smother it to death,”

“The domestic bee has never ceased surprising us.” Arnold added.

In recent studies, scientists have shown that Asian honeybees in a similar strategy, when they surround hornets inside the beehive, causing them to die from the heat.

The heat strategy or thermo-balling strategy is often used to fend off and eradicate invaders, for the most part Hornets. Hornet’s body design is durable outer shell with hard cuticle, which dense the bee’s stingers to poke through.

Although, scientists knew from earlier studies that various subspecies of the domestic honeybee (Apis mellifera), which form comparable balls around hornets, couldn’t raise the temperature high enough to finish off the heat-tolerant hornets, according to the study’s first author, Alexandros Papachristoforou of Aristotle University of Thessaloniki, Greece.

It had also been shown that the mobbing bees go for the gut, targeting the hornets’ abdomen, which is critical for the insects’ ability to breathe.

By pumping their abdominal muscles, the hornets bring in air through small openings called spiracles, which are covered by structures known as Tergites when air is released.

To find out whether the bees could be blocking the hornets’ breathing, the researchers monitored their respiration under normal conditions and those designed to mimic the balling behavior, in which they covered either two or four of the insects’ tergites.

In this study, however, the Hornets’ respiration declined by about 33 and 87 percent, respectively.

Next, they tested whether the bees could kill hornets whose Tergites were held open with tiny plastic blocks. They found that the bees took twice as long to kill such manipulated hornets.

“To kill the high-temperature-tolerant hornet, Cyprian honeybees have developed an alternate strategy to thermo-balling and stinging,” Arnold said.

“They appear to have identified the hornets’ ‘Achilles heel’ by asphyxiating the predator. This ability indicates that under extreme conditions, honeybees can present a high level of adaptation in order to survive.” Arnold explained.

The study is published in the September 18, 2007, issue of Current Biology, a publication of Cell Press.