An aggressive wasp with no known predators is being found in record numbers in Western Australia, with suburbs in Perth’s Hills and foothills most at risk.
- European wasps have a painful sting and can devastate horticultural industries
- WA is the only place in the world to prevent them taking hold despite constant invasion
- But more queen wasps are arriving in WA on freight and cargo from interstate
At least 128 European wasp nests were discovered over summer and it is estimated there are up to 100 more, almost double the number found last year.
Super nests of up to 20,000 wasps have been discovered in WA, prompting the Department of Agriculture and Food to warn the wasp could have a devastating impact on the state’s horticultural and agricultural industries, as well as its outdoor dining culture.
“They are complete and utter ecological vandals,” Department entomologist Marc Widmer said.
He said if the wasps became established in the state it would not be surprising to see them in vast numbers.
“[That is] 20,000 wasps per hectare in the air all throughout the wasp season, 10 months of the year,” Mr Widmer said.
“Ecologically it would be a disaster.”
Wasps hitch rides on cargo
WA is the only place in the world to have successfully stopped the European wasp from taking hold thanks to eradication efforts over a 40-year period.
However, as its population on the east coast expands, more queen wasps are moving across the border on freight and cargo.
While in Europe the queen wasps die in the cold winter months, WA’s warm climate, soft soils and plentiful jarrah power poles make conditions perfect for the wasps to proliferate.
“In Western Australia we have the capacity to get these super nests,” Mr Widmer said.
“The nest carries on through winter and it’s turbo charged by the time spring comes with all these queens.
“They’ve got no predators, they’ve got no agents that control them like they would in their native range, so they are off and free.”
Insects could change WA’s outdoor lifestyle
The aggressive wasps are attracted to sweet foods and raw meat.
Mr Wider said they posed a danger to the soft fruit industry in WA, particularly grapes. They also attack bee hives and other animals, including hatching chicks.
The wasps are also notorious for spoiling outdoor barbecues and picnics, and could significantly impact people’s behaviour in the warmer months.
“You would change your outdoor way of life — you wouldn’t feed your pets outside, you would be worried about your dog or your cat swallowing a wasp on their food,” Mr Widmer said.
“You wouldn’t have drinks outside if they were around. You would have wasps buzzing all around your picnic tables and your outdoor events.”
Hills suburbs most at risk
The wasps have a painful sting and while there has not been a fatality recorded in Australia, they have been responsible for deaths overseas.
How to identify a European wasp
- Black feelers and antennae — similar looking paper wasps have orange/yellow antennae
- They fly with raised legs — all other wasps dangle their legs
- Fly in and out of a hole in the ground
- Scavenge on human food, drinks and pet food
In the 40 years since the wasp was first discovered in WA, 1,060 nests have been destroyed.
However, with a single wasp nest releasing up to 6,000 queens, their numbers grow exponentially.
“I am very concerned this year because we know there are so many wasps out there and they are in areas where there are fewer people,” Mr Widmer said.
“Lesmurdie, Mundaring, places like that, also at the back of Wattle Grove up in the foothills. These are the areas we are really concerned about.”
Hot spots for European wasps
- Darling Scarp suburbs including Lesmurdie
- Foothills including Wattle Grove
- City of Swan
- Industrial suburbs such as Welshpool, Kewdale, Bibra Lake, Canning Vale, Malaga and Wangara.
(source: Agriculture Department)
The spike in numbers has forced the Department to double its staffing resources and the number of traps it deploys.
It has also appealed to the public to look out for European wasps, which are differentiated from other wasps by their black antennae.
“People don’t know what a pest they are because they are not here, and when they become established they realise,” Mr Widmar said.
“But the trouble is, establishment is forever.”