Asian Hornet

Asian Hornet
Vespa velutina, Frelon Asiatique

The Asian Hornet is a relatively new arrival in France entering it is thought, in Bordeaux on-board a pottery shipment from China. It rapidly spread through the surrounding area following the water courses and we first saw Asian hornets in our area of Poitou-Charentes in late 2008.  In September 2009, there were sightings north of Paris. Click here for a map that shows its rapid expansion across France. It is now said that wherever you are in Poitou-Charentes, you are only less than 250m from an Asian Hornet nest…

The most comprehensive summary of the key characteristics can be found on INPN, the French National Natural Heritage site (Inventaire National du Patrimoine Naturel) but this page is only available in French so we have summarised some important features …..

Identification

The Asian Hornet is smaller than the European Hornet and much darker – queens are up to 3cm and  workers 2.5cm. Their thorax is velvety black/dark brown with brown abdominal segments bordered with fine orange band and the 4th segment is almost completely orange or yellow in colour. Legs are brown with yellow tips and their head black with yellow/orange face.

Nest

The beige / brown nest is constructed using paper mâché made from chewed tree and plant material. Several wafers of cells are surrounded with double skinned reinforcements – sometimes 5 or 6 layers deep. Unlike the European hornet the entrances are on the sides, not on or near the bottom. European Hornets construct nests in cavities, whereas the Asian builds a suspended nest – normally in open roof spaces or trees. The nests are spherical/oval in shape and up to 1m height / 80cm diameter – usually 4 to 15m from the ground. The nest is well camouflaged and often difficult to see until trees lose their leaves.

Here are some pictures of a small nest that we destroyed in the summer of 2009 (click on any picture to view the slideshow)

Asian Hornets and Bee hives

Asian Hornets are a key predator of bees and if unchecked they can cause catastrophic failure of  a hive. It has been recorded that in urban situations some 80% of an Asian Hornet’s diet is bees and in rural situations this drops to about 55 – 60% with the remainder being insects, butterflies and sugar heavy fruit. Their mode of attack is is to hover about 30cm from the entrance to a beehive, pouncing and grabbing the slower returning bees carrying heavy pollen. They take them to the ground and cut off their heads using their mandibles  before taking them to a perch where they remove the legs and wings. Finally, they carry the body back to their nest to feed the larvae.
After locating hives, the hornets prey in numbers which can have a devestating effect on the bee colony as they reduce bee numbers and therefore the amount of pollen / nectar flow entering the hive. This results in the death of the developing larvae. The queens will then either stop or reduce laying eggs leading to a sharp decline in the colony which will also be susceptible to disease due to the poor conditions within the hive.

Risk levels to hive

  • 2 hornets – a healthy hive can cope and maintain normal activity
  • 3/5 hornets -  they disturb the normal activity of the hive and weak hives may succumb
  • 5+ – even healthy hives will have problems unless solution found.

Lifecycle

Asian Hornets only live for one year – at the end of summer the workers and males die off and the queen hibernates. In early May she re-awakens and starts looking for a possible nesting place – we often see queens searching our barns and garden for a place to settle in Spring. If you see an Asian Hornet at this time of year then it is most likely a queen so dispatching it now will reduce the number of nests in the area.

Asian Hornets and Humans

Their sting is similar to ordinary wasps and each hornet is capable of stinging multiples time. They are non-aggressive unless provoked by getting too close to nest, the waving hands or direct attack. The danger from hornets is not the individual sting but multiple stings from busy nests – each hornet is able to sting several times. Obviously, people allergic to stings need immediate treatment as with any other sting.

Removal

Small nests at the start of the season Spring can be destroyed by a powerful aerosol spray (see the one we destroyed above). However larger nests need professional removal – either by the Pompiers or a professional exterminator. To find your local removal expert, ask at your Mairie – Asian Hornets are a notifiable pest and therefore all Mairies should be able to tell you how to get rid of them DO NOT TRY TO REMOVE THEM YOURSELF as this can be very dangerous – on entering a nest, 90% of the Asian Hornets present in the nest will come out to attack you. Recently a local farmer tried to shoot a large nest down and was lucky to escape without serious injury – definitely not a good idea! The local Pompiers came and removed the nest, it was at least 1m long and must have contained thousands of hornets – oowww!

Protecting your hives

The best idea is to make traps and place nearby – Planete Passion have a template for simple trap to follow. We have also found that a long handled badminton racket makes a great deterrent if you see a hornet hovering above the hive!

Natural Predators

It has been reported that several species of birds attack nests and feed on the young including magpies and jays.

Leave a Reply