Lincoln University ecologist Dr Jon Sullivan has a unique way of discovering the arrival of new species in New Zealand.
He opens his office window and they just fly in.
Recently, the first New Zealand recorded specimen of the European small tortoiseshell butterfly, Aglais urticae, did just that.
He said it is a northern hemisphere butterfly, with caterpillars that feed on nettles, including the small nettle, Urtica urens, which is abundant in Lincoln.
“I photographed, collected it, identified it on iNaturalist NZ, and reported it to Biosecurity New Zealand.
“It's a complete mystery how a European butterfly showed up flying about at Lincoln, New Zealand. A colleague at Manaaki Whenua-Landcare Research tells me that they're cold-hardy butterflies in the United Kingdom that would likely do well here if they established.”
Dr Sullivan said the only other Southern Hemisphere records of the butterfly, from the Global Biodiversity Information Facility (GBIF), are from Indonesia (with four records in 2009) and one well north of Cairns, Australia, in 2003.
He initially thought it was a more common visitor, a painted lady butterfly.
He asked people to keep a close eye out for colourful orange butterflies in and near Lincoln to see if they had established in the area.
“They're about the size of a yellow admiral butterfly (a common local butterfly).”
The Ministry for Primary Industries (MPI) is investigating but believes it is most likely to be a solitary find and not evidence of a whole population.
It is seen as most likely a hitchhiker (as a pupae) on imported commodity from an area where the butterflies are prevalent, and is not regarded as posing any significant biosecurity threat.
However, if people believe they have seen one of these butterflies, they can contact MPI on 0800 80 99 66.