Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Buzz over wasp excavation

Thursday 18 Feb 2016

Landcare Research scientist Dr Bob Brown excavates a wasp nest.

Landcare Research scientist Dr Bob Brown excavates a wasp nest.

Coming face-to-face with thousands of aggressive wasps is just a typical day at work for New Zealand researcher Dr Bob Brown.

The Landcare Research scientist has been excavating wasp nests around New Zealand to discover more about a newly recognised mite species. The mites could be a promising biocontrol agent against the pest, which stings the country’s primary industries around $130 million a year. Brown first found the mite, which has recently been described and named Pneumolaelaps niutirani, in wasp nests in 2012.

In colonies where the mites are present, he has found the nests to be 50 to 70 per cent smaller than those which are uninfested.

Since the mites have also been found in low numbers in honeybee hives, Brown wants to confirm that the mites do not pose a threat to bees.

A recent video Brown took of himself excavating a nest at a property in a Christchurch (New Zealand) suburb has been viewed more than 500,000 times.

The video shows him dressed in a bee suit, carefully digging at soil to access and remove a nest to later inspect for mites. At first there are only a handful of wasps flying about, but within a matter of seconds there is a large angry swarm. Venom soon coats the camera lens.

Brown said he was surprised by the size of the nest in the clip.

“I thought it was going to be a small nest because there wasn’t very much wasp traffic in and out of the entrance.”

He estimated the nest, with 11 different layers, housed between 3000 and 4000 wasps.

“It was big for this time of year,” he said. Wasp nests were at their largest during autumn. He believed if the nest had remained undisturbed it would have had an additional three to five layers.

After the “quick” 10 minute excavation, he walked away with only one sting to his arm.

A later inspection of the nest found no mites.

Brown will continue excavating wasp nests in the Canterbury, Otago, Wellington, Southland and West Coast regions over the coming months to gather mites to test their association with bees.

Bee larvae would be fed a solution containing stable isotopes and the mites later inspected to see if these appear in their systems.

“Stable isotopes are molecules that act like a chemical marker that we can track. If the stable isotopes are found in the mites this will conclusively tell us they are feeding on the bees because there is no other way for them to acquire these molecules,” Brown said.