AFRICAN honeybees have devised a bizarre but highly effective tactic for
dealing with unwanted guests鈥攖hey lock them up in prison cells inside
their hives. This penal policy keeps a lid on the parasites and, if necessary,
buys the colony time to escape.
Peter Neumann of the University of Halle-Wittenberg in Germany and colleagues
studied how bees in South Africa defend themselves against the small hive beetle
Aethina tumida, which is about half the size of a bee. The beetle raids
the bees鈥� food reserves and eats their larvae.
The beetle is 鈥渂uilt like a tank鈥�, and the bees have little success tackling
invaders directly, says Neumann. Instead, they literally imprison the beetles in
small cracks within the hive, a tactic involving sophisticated teamwork called
鈥渟ocial encapsulation鈥�. 鈥淲hile some bees build the prison, others continuously
guard the beetles to prevent escape,鈥� says Neumann. The jailhouse is made from
tree-resin collected by the bees, and building can take up to four days.
Advertisement
Hive beetles are rarely a serious threat to African honeybees because they
deal with them so efficiently. In one instance, Neumann found that a colony of
bees managed to imprison over 200 beetles, although the colony did eventually
abandon its nest after the heavy infestation. The results will be published in a
future issue of Naturwissenschaften.
In the US, however, honeybees are at the mercy of the beetle invaders, which
were accidently introduced to the country 3 to 5 years ago. 鈥淚t has become a
major honeybee pest in the US,鈥� says Neumann. 鈥淥nce colonies from European stock
are infested they are basically doomed, because these bees lack the behavioural
resistance mechanisms of African honeybees.鈥�