A Portuguese millipede at Te Kopahou information centre Photo: RNZ/Mary Argue
The invasive Portuguese millipede plaguing residents on Wellington's south coast has spread beyond the region.
When Wellingtonians sounded the alarm about infestations of the scaly black creature - discovering them in shoes, bags and even beds - entomologist professor Phil Lester predicted the species would appear elsewhere.
The Ministry for Primary Industries (MPI) has now confirmed the millipede has been found in New Plymouth, and that it's also awaiting samples of a specimen from Nelson - which if confirmed, would be the first known report of the species in the South Island.
MPI said the reports were the first outside of the main populations in Wellington, where the millipede is thought to have been established for the past 20 years.
A spokesperson said there would be no formal response to its spread, "however Biosecurity New Zealand will provide advice to local authorities where required".
Lester said given the Portuguese millipede's "massive abundance" in parts of Wellington, expansion was inevitable.
"You'd expect the millipedes to contaminate cars, luggage, and containers ... and be moved around the country."
He said people and authorities in New Plymouth would be wise to act now.
"The residents of Owhiro Bay will tell you, if it gets established and gets in high numbers, it's a real pain in the neck.
"So they are suffering from it - as we speak almost," (the millipedes emerge in spring and autumn).
Lester said one positive identification of the species was likely to be the tip of the iceberg.
"If you can do anything to avoid it getting established, that would be optimal. It would solve a problem down the track."
He said people should report sightings and submit samples to MPI, and spray if possible.
It would be ideal if councils got involved in stopping its proliferation, he said, but acknowledged funding and resource constraints meant that wasn't always possible.
Lisa Hardegger, leader of Taranaki Regional Council's biosecurity programme, said she was aware of the millipede's sighting in New Plymouth - submitted to iNaturalist (a website dedicated to identifying species) in June - but said there'd been no direct contact with MPI or Biosecurity New Zealand since.
She said she wasn't aware of any other sightings in the area, and encouraged residents to report anything they suspect to be the millipede to MPI.
"The Portuguese millipede is not part of our Regional Pest Management Plan and is considered more of a nuisance pest rather than a threat to ecosystems or human health. Of course, we would prefer it does not become established or widespread in the region."
Because the species wasn't on the pest plan, the New Plymouth District Council said it didn't have a role in managing it.
Lester, who is also part of an advisory group researching the Portuguese millipede and ways to control its population in Wellington, said trials of a parasitic nematode as a biocontrol agent were due to begin in the next couple of weeks.
The microscopic nematode Steinernema feltia wriggles its way into the millipede's body and reproduces. Eventually, the offspring become so numerous they burst out of the host, killing it.
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