Asian hornet
Jan 15 2018

All eyes open for killer hornets

Asian hornet, Vespa velutina

The Asian hornet is native to Southeast Asia, but it was accidentally introduced to France and is rapidly spreading. There are major concerns and a high possibility that it could come to Britain in soil associated with plants (such as imported trees), on or in untreated wood, with fruit or cut flowers, or in freight containers or people’s vehicles.

So we all need to keep our eyes peeled. The earlier one is spotted and reported the more likely it can be dealt with effectively, before it gets established. One mated queen could spawn a small army!

Their most distinctive features are their almost entirely dark abdomen (with just a tiny bit of yellow) and their yellow tipped legs, both different from our European hornets. It is also slightly smaller than our native hornet.

European hornet, Vespa crabro

On the other hand, our native European hornet is a fantastic creature.

Much larger than the common wasp, its wings are reddish-orange, its abdomen striped yellow and brown, and its legs are brown (no yellow). They create amazing nests from chewed bark and plant material, often in hollow trees. It is generally not aggressive unless threatened, but can be defensive of its nest and food sources – only the female can sting.

As a rule of thumb, leave it alone and it will leave you alone.

Biggest threats

What makes the Asian hornet of greatest concern is its ability to kill honey bees. One is reported to be able to kill 40 bees in a minute, but a group can kill 30,000 in just a couple of hours.

If it gets here, this poses a serious threat to our long-suffering honey bees.

They are also far more aggressive than our native hornet and can deliver some nasty stings. Using its 6mm-long stinger, it injects potent venom (made up of eight chemicals) into its victim.

Be warned, it can sting multiple times. Images of the holes that can be left in people’s flesh are rather disgusting and the venom can cause an allergic shock that can be life-threatening.

Clever tactics

In Asia, their native bees have evolved an impressive technique for dealing with Asian hornets.

They will allow a hornet scout into their hive, which if they let go would return later with reinforcements for a killing spree. Giving it a false sense of security, the bees then lure the hornet in and attack. They surround the hornet in a ball and vibrate their flight muscles to raise the temperature and carbon dioxide levels within the ball. The bees can withstand temperatures just above that of the hornet, which dies.

So the majority of bees survive and the dead hornet cannot go back to its hive to bring others, so the hive in safe once again.

Sadly, European honey bees have no such defence.

Action stations!

If you think you have seen an Asian hornet please report it immediately, with a photo if possible, to alertnonnative@ceh.ac.uk

But take care to not disturb an active nest!

If you would like to know about other invasive species and what we are doing to combat them, have a look at this issue of Wood Wise.

No Comments

Post a Comment
X