Science - September 4, 2017

Study on Asian predatory wasp

Text:
Roelof Kleis

The Wageningen bee experts will itemise whether and how beekeepers can prepare for the arrival of the Asian predatory wasp.

© Danel Solabarrieta

The Asian predatory wasp (Vespa vetulina) is an exotic vespoid that came over from China to Europe in 2004. It is believed that a queen reached France packed in boxes of pottery. From that point, the wasp has slowly been spreading across the continent. The critter has since been observed in all countries neighbouring to the Netherlands.

Time
‘It has recently been seen in the Belgian town of Doornik, about seventy kilometres from the Dutch border’, says bee researcher Bram Cornelissen of Biointeractions and Plant Health. ‘That means the insect is coming pretty close to our grounds.’ According to Cornelissen, it is only a matter of time before the first Asian predatory wasp is seen in the Netherlands. ‘The animal can cover 30 to 40 kilometres each day through flight. This can be more if it catches a transport, of course.’

But it won’t reach the Netherlands until next year, at the earliest. The season has now ended. Cornelissen hopes that by that time, he will know the possible consequences of the arrival of the wasp for beekeepers and for pollination in general. The Asian predatory wasp feeds on insects, but is also attracted to offal. According to Cornelissen, the honey bee is one of the main courses for the predatory wasp.

The Asian predatory wasp is an invasive exotic species. European legislation obliges us to fight it.
Bram Cornelissen

‘The predatory wasp’s method is to have several individuals hanging in front of the beehive’s entrance. There they wait for the return of bees, which they proceed to pick out of the air.’ This is not a friendly business. The bees are cut into pieces by the wasps’ jaws, and the ‘meat’ is transported back to their hive. They can decimate entire populations in this manner, or at least greatly weaken them.

Vespa_velutina3.jpg

Individual bees have very little to say about the much larger wasps, which can grow to over three cm in length. Bees only stand a chance by cooperating, says Cornelissen. The Dutch Ministry of Economic Affairs asked him to find out which measures beekeepers could and should take. ‘The Asian predatory wasp is an invasive exotic species. European legislation obliges us to fight it.’

Alarm
The first challenge to do so is the identification of the Asian predatory wasps itself. According to Cornelissen, about thirty photos of possible sightings have reached the Wageningen bee group in the past few weeks. All of which were false alarms. This is mainly due to the resemblance between the Asian predatory wasp and its European cousin, the Vespa crabro – better known as the European hornet. Other species of wasps and hoverflies also make it considerably more difficult to adequately identify the wasps by non-experts.

A specially created WUR website (in Dutch) contains a factsheet that can offer some support. If anyone still thinks they see one, they are requested to notify waarneming.nl of telmee.nl.


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