Scientists trying to locate the samurai wasp have confirmed it's somewhere in Australia but they still don't know exactly where the powerful biocontrol agent is.
The tiny insect is only the size of a sesame seed but is considered one of the best predators against the highly destructive brown marmorated stink bug.
After three years of detective work, national science agency CSIRO has confirmed the wasp is in Australia by having specimens collected last century correctly identified.
"It's definitely out there, we just haven't been out there at the right time or exactly the right spot," CSIRO's Valerie Caron said.
The hunt led them all the way to Canada, where a wasp found in Australia in the 1990s was sitting in a museum's insect collection.
The specimen was analysed by one of the world's leading taxonomists who confirmed the samurai wasp was first recorded in Australia in 1914 but given a different name.
"They're tiny, they're very hard to identify," Dr Caron said.
"At least it is here, that's the good news, we just don't know exactly where."
The samurai wasp was initially found in Japan.
While it can’t sting humans it's a fierce predator of invasive insects, and kills the eggs of its hosts and lays its own.
The wasp's preferred host is the highly invasive brown marmorated stink bug, which has devastated crops in other countries.
The stink bug feeds on more than 300 plant species including key agricultural crops.
Despite a number of incursions the pest hasn't taken hold in Australia, but if it does scientists want to be ready to deploy the wasp as a weapon.
"We do need to know where it is so we can collect it, ideally we would mass rear it and be ready to release when the brown marmorated stink bug comes," Dr Caron said.
New Zealand has already approved the samurai wasp's mass release should the stink bug take hold there.
The CSIRO scientists are now planning more sampling across a wider range to increase their chances of catching the samurai wasp in Australia.
