For decades, New Zealand’s invasive wasps have run the course of the place with no natural enemy to control the growing numbers. But that will soon change as the green light is given today to introduce two insects from Europe to control the pest.
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A beetle and a hover fly fight the wasps, which are damaging the environment. Source: 1 NEWS
The Tasman District Council, which has a major wasp problem, applied for the bio-control funds, a hover fly and a wasp nest beetle.
The regulatory authority, the Environmental Protection Authority, assessed their safety.
“The reason it’s safe is because these two insects only attack wasps. This has been found both where they come from in Europe and elsewhere,” said Chris Hill, general manager for Dangerous Substances and New Organisms.
Invasive German and common wasps have exceeded biodiversity in native forests, causing farmers and beekeepers financial pain that costs them about $ 70 million annually.
Beekeeping hives are often decimated by wasps.
“They’ll sit outside the hive and work their way into it, they’ll kill the larvae for being protein feeders, and they’ll kill the bees, but then they’ll steal the nectar too,” said Wendy Lane, a beekeeper near Nelson.
The German wasp came here in the 1940s, tucked away on aircraft parts, while the common wasp arrived in the 1970s.
“When the wasps got here, they found a wasp utopia, so to speak, they had no real natural enemies here. They left all their parasites and also found an abundance of honeydew,” said insect ecologist Richard Toft.
But “wasp utopia” is about to come as a shock.
The hover fly and the beetle both target wasp nests.
“The hover fly manages to get in there and lay eggs in the nest, and its larvae will eat the wasp larvae. So if you get enough of those parasites in the wasp nest, they can affect the wasp population,” Toft said.
The Tasman District, with its beech trees covered with honeydew, has the highest density of wasp nests in the world at 30 to 40 per hectare.
The wasps have monopolized the honeydew, robbed other insects and animals of a food source and disrupted the ecosystem.
Bob Brown, wasp expert at Landcare Research, called the introduction of the new insects “monumental” for conservation.
Attempts were made in the 1980s and 1990s to suppress wasp numbers by introducing smaller wasps from Israel and North America, but it didn’t work.
The new beetle and hover fly are expected to be effective, but the only question is how much?
“It’s not a silver bullet, but it’s a tool in a toolbox,” said Paul Sheldon, the Tasman District Council’s Biosecurity and Biodiversity Coordinator.