Asian hornet predictions in the UK
With the ability to spread at the rate of 70-80 km per year, what are the prospects if the Asian hornet (Vespa velutina) takes hold in the UK?
The first Asian hornet nest was discovered and destroyed in the UK last year, so researchers have tried to predict its spread in Britain if it can establish itself. Their work is inevitably hypothetical, but it has been based on the eight-year experience of events since the arrival of the hornet in France.
Prevention of the spread of the Asia hornet is a pressing concern because in France its diet consists about 50% of Apis mellifera, with other valuable pollinators contributing to the rest.
The researchers set about creating a mathematical model to try to predict the track of the potential invasion. They made some assumptions: the average distance for a queen to fly to set up a new nest is 28 km, but fortunately it is not expected to do well as it travels north and they have tentatively expected it not to establish itself at all in northern England. They have even managed to factor in eradication attempts.
After 10 years, the invasion could be widespread with more than 50,000 nests with as many as five nests in each km2 in certain areas. After 2o years, an area’s carrying capacity is expected to have been reached.
Uncontrolled expansion will be disastrous say the researchers, so detection and eradication is vital. They think that limited local searching would result in a a finite — and often short — time until control efforts fail. New incursions are likely to increase over time as the hornet becomes further established in mainland Europe.
In France, only 48% of nests have been detected and this is not enough to control an invasion, say the researchers. Nonetheless, valuable lessons can be learned from the French experience.
The year 2017 is thought to be critical to the immediate future — if more nests are found, the prospects are not good, but if none are discovered this will be reassuring giving the possibility that the south of England is not a conducive environment for the hornet.
The full paper can be read here.
Meantime, Vita suggests putting its Apishield Asian hornet traps in place to monitor — and to protect.