CYPRIOT honeybees dispatch enemy hornets by surrounding them one at a time in large numbers and suffocating them, a researcher in Athens has discovered.
Scientific magazines are cautiously intrigued by the possible discovery of Alexandros Papachristoforou, a researcher who studied the bees in Cyprus for his doctorate at Aristotle University in Thessaloniki.
Until now, it was thought bees had only two ways of killing their enemies.
Either they stung them, which meant instant suicide, or they gathered around a hornet in groups and raised its body temperature until it died.
The latter method was discovered by Japanese scientists.
It was assumed that the bees in Cyprus did the same thing when they clustered around a hornet. However, Papachristoforou tested the hypothesis on the island and discovered that the amount of heat the group of bees raised was not enough to kill the insect.
His team found that bees in Cyprus could raise the temperature inside the clump to 44 degrees Celsius but outside temperatures could also reach that level, so he deduced there must be another reason for the hornets` death.
Experiments revealed that the particular type of hornet that plagues hives in Cyprus – the Oriental hornet – could withstand temperatures of 50 degrees Celsius.
Hornets, which are a type of wasp three times the size of a bee, emerge in late summer, attack hives, kill thousands of bees in a short space of time and eat their larvae.
The hornet can snap off the heads of their smaller cousins with a single bite.
But Papachristoforou’s team noticed that during an attack the Cypriot bees first targeted the hornet’s abdomen, where they breathe through contraction of the muscles.
However, it can still take an hour or two for a cluster of bees to kill one hornet while the enemy wasp can do a lot more damage to the hive in the same length of time.
The hornet problem is nothing new to beekeepers in Cyprus, who confirmed yesterday that they can lose up to one third of their stocks annually because of the attacks.
Pambos Christodoulou, the head of the beekeepers’ association, said he was aware of the experiment, having assisted Papachristoforou when he was in Cyprus.
“He is right that hornets are a big problem for the hives,” said Christodoulou, who added it was hoped the discovery could lead to some way forward to solve it.
“Perhaps it will lead to some easier way to protect our bees.”
Christodoulou said every year beekeepers put out bait for the hornets. They used to use poison but no longer did, he said.
Now the place bait on “glue mats” around the hives, but Christodoulou said it wasn’t enough. He said they hives have to be monitored around the clock.
“If you stay away for any length of time, you could lose all of your bees,” he said.
