Asian hornet - Vespa velutina

Charles Smith-Jones says we should be on our guard for this large member of the wasp family that has settled in many parts of Europe and poses a serious threat to pollinators

- Charles Smith-Jones

The Asian hornet has only been present in western Europe for less than two decades, but this native of south-east Asia is already causing concern as a serious threat to honeybees. It is a generalist insect hunter but has a tendency to devastate colonies or apiaries and, as such, is a significant threat to these pollinators so vital to the environment. As a result there is alarm among conservationists because of the effect on natural biodiversity. Others who are heavily reliant on the activities of honeybees, such as beekeepers and fruit farmers, are equally worried.

Once a honeybee colony is located, the hornets will return to it in increasing numbers and relentlessly prey on the bees until the colony collapses. The hornets sit outside the hive or colony, capturing the worker bees as they come and go, then cutting them apart and feeding the thoraxes to their young. They will also prey on native pollinators including wasps and hoverflies.

Coloniser

The species is highly invasive and a single Asian hornet queen can produce many thousands of offspring. Once mated they travel over 40km a day, quickly establishing colonies in new regions. By the end of the breeding season the females of her final brood, known as gynes, will themselves disperse and colonise new areas. Evidence from France suggests that a single colony will produce up to 350 gynes between September and November.

It is believed that the first Asian hornets to reach Europe arrived in boxes of pottery from China in 2004. Within five years, thousands of nests had been reported around the Bordeaux area and by the end of 2015 they were being recorded all over France. They have since spread in turn to Spain, Portugal, Italy, Belgium and Luxembourg.