Asian hornet in the UK: Update and Request for Heightened Vigilance.
As you are aware, Vespa velutina nigrothorax, the yellow-legged hornet (a.k.a the Asian hornet) was found in the UK last season. Adult hornets are voracious predators of honey bees and other beneficial insects, resulting in colony losses in France. In September 2016, foraging Asian hornets were reported near Tetbury in Gloucestershire, and a trapped individual was reported from Somerset. The nest near Tetbury was found and destroyed by National Bee Unit Inspectors and members of the Wildlife team in the Animal and Plant Health Agency. Despite extensive field inspections, no further foraging Asianhornets were sighted in Somerset. Whilst this is good news, the ability of the Asian hornet to spread rapidly means that we must remain vigilant and aware of any possible activity across a wide area and there is an opportunity for us all to monitor and trap any potential foundress queens.
Around April, surviving V. velutina queens begin a small primary nest, often in a sheltered location such as in the eaves of a roof or in a garden shed. Here they raise the first clutch of workers who take over the queen’s foraging duties. At this stage the nest grows quickly, and the hornets often move to establish a secondary nest where there is more space to expand.
These nests can become very large, and are often located high up in the tree canopy, close to a food source such as apiaries.
From late September to October, the mature nest produces males and then virgin queens which mate and disperse. However, the beginning of this stage of nest reproduction can vary, depending on climatic conditions. A single mature nest produces on average 11 foundress queens after taking into account overwintering mortality of the potentially hundreds of queens that first disperse in autumn.
A consortium of scientists from the NBU and the Universities of Warwick and Newcastle have used data on the spread of the Asian hornet in France to develop a mathematical model that can estimate the hornet spread in the UK. The highly mobile nature of the hornet means that the range of possible additional nest locations in 2016, estimated using the model, covers a wide area.
Please see the map showing the potential spread of Asian hornet in 2016. The dark orange squares represent the locations of Asian hornet discoveries in Tetbury and Somerset. The yellow area defines a boundary, outside of which we would not expect to find a nest.
Asian hornets can be trapped by using either commercial traps to prevent populations expanding. Asian Hornet Identification sheet.
Alternatively please use the online form.