Vespa velutina nigrothorax, the yellow-legged hornet (a.k.a the Asian hornet) was found in the UK last season. The first European incursion of this hornet was reported in France in 2004. The Asian hornet has since spread around 80-100 km per year, invading Spain, Portugal, Italy, Germany and Belgium. 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 Asian hornets were sighted in Somerset. Since then, there have been a number of nests discovered and destroyed in the South of England. 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 with spring fast approaching, there is an opportunity for us all to monitor and trap any potential foundress queens.
In spring, 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, (see images on BeeBase for further details).
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. In France, 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.
There is a helpful Asian hornet identification sheet and poster , with contact details of Committee Members who are able to help identify and report these insects.
Should you find a suspect Asian hornet or nest, please contact the Non Native Species Secretariat immediately using their alert email address: firstname.lastname@example.org giving as much information as possible. Please include details such as your name, the location where the hornet was found and if possible an image of the specimen. Please do not put yourself in any danger of getting stung when trying to take a photo. Even if you are unsure of whether it is an Asian hornet, send it in anyway – it’s better to be safe than sorry.