New threat to European honeybees
A new threat to honeybees is spreading rapidly in France and may reach the UK within the next few seasons. The invading predator is the Asian hornet (Vespa velutina nigrithorax), and it has the power to destroy a honeybee colony within weeks. Vita (Europe) Ltd, the UK-based honeybee health company, plans to have a hornet trap ready by the end of this season.
First identified near Agen in France in 2004, when a farmer destroyed two of its nests, the Asian hornet is thought to have arrived in Bordeaux from China, in a consignment of pottery destined for the horticultural trade.
By 2007, apiaries around Bordeaux were suffering up to 70% colony losses as the Asian hornet munched its way through its prey. Unlike the European hornet (Vespa crabro) which will eat the occasional honeybee, the Asian hornet is slightly smaller but far more deadly to honeybees. Groups from five to 50 hornets hover in front of a hive, picking off single honeybees, decapitating them and stripping off their wings and legs before making off with the “meat ball” to their nest to feed their young.
As the attacks continue, the honeybee colony stops flying and has to consume its own stores, eventually weakening it to such a point that an invasion force of many hornets enters the hive to rob it out.
Studying the interactions between hornets and honeybees, Dr Alexandros Papachristoforou and a team at the University of Thessaloniki have found how the Cypriot honeybee (Apis mellifera cypria) withstands the Oriental hornet (Vespa orientalis), which in Greece and Italy has long posed similar threats to honeybees. The Cypriot bees have developed a unique defence. They engulf the hornets en masse killing them by “asphyxia-balling”.
But in France, bees are not so well organised, since they have not yet co-evolved with the predator. Instead of “balling” the hornets, brave bees vainly sting them to death, but their stinger cannot penetrate the hard exoskeleton of the hornets. As yet honeybees in France have developed no effective defence.
Dr Max Watkins of Vita (Europe) Ltd said: “As yet there seems no way of controlling the spread of the Asian hornet, despite the best efforts of fire fighters who are the only ones equipped to destroy their nests, which are usually high in tree tops. We cannot tell if or when the hornet might reach Britain, but since it is already near St Malo in northern France and since it seems to survive well in these climates, its arrival in the next few seasons looks likely.
“We have been testing traps with Dr Alexandros Papachristoforou, who is researching the hornet with colleagues in Greece and France, and we have now selected the most successful one for manufacture. The hornets (and wayward wasps) are lured into the trap and all the beekeeper need do is empty the trap at the critical time of year. We expect to have the trap patented and in production by the end of this season.”