Introduced wasps are not bad, but the media say so

Introduced wasps are not bad, but the media say so

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Introduced wasps are not at all bad, but the media portray the story as if they’re going to kill all living things and rival their mates.

Introduced Asian and Australian paper wasps may be playing a more complex ecological role in New Zealand than previously thought. They can even help to control some agricultural pests according to the Bio-Protection Research Centre.

“Introduced wasps are regarded as an ecological pest in New Zealand because in beech forests they compete with native species for honeydew as a food,” said Bio-Protection Research Centre Director Prof Travis Glare, one of the paper’s authors.


“However, this study shows their ecological roles may be much more complex than realised and may contribute to biocontrol of major agricultural pests.”

Research published from NeoBiota shows a new method to analysing what wasps eat which does reveal a picture of what’s in their diet.

In the past, methods of testing insects stomach contacts or faeces only could reveal what they had recently eaten within hours. Nests had to get tested more than once to reveal any difference in seasonal diets.

A new method was developed of testing prey DNA in the faeces deposited in wasp brood cells (where larvae are growing). It can reveal what wasps ate recently and what they have eaten throughout their lifespan of the nest.

48 wasp nests were collected belonging to two species of paper waps Polistes chinensis and P humilis from Auckland’s region. Two faeces samples from each nest, one from brood cells of the outer layer of the nest and the other from brood cells in an inner layer.

“While the presence of marine DNA may correspond with actual consumption, it may also reflect insects feeding on carrion waste washed up by the tide or feeding on the by-products of human activity (e.g. markets, fishing harbours, food waste,” the authors wrote.

Analysing wasps’ diets needs to be further ‘refined’ according to Prof Glare as they’ve developed a much more extensive role in New Zealand’s ecosystems than previously thought.

“These results show for the first time that wasps do indeed prey on, and help to suppress, agricultural pests, as well as preying on native insects. We need to clearly understand what they eat, and when, to understand the impact they are having on our native species, and also the ecosystem services they might provide,” he said.

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