Tracking down Tasmania's rare, flightless pandani moth

Tasmania, as entomologist Peter McQuillan puts it, is "a Noah's Ark of ancient species long since lost elsewhere".

One of those living relics is the pandani moth.

The bronze-brown insect is large for its species, with big legs and a purplish reflective hue under light.

It has also lost the ability to fly, moving about mostly by hopping — although it can glide down from the Tasmanian pandani, a slow growing alpine plant that the moth lives in.

It was first seen in the 1980s, given a formal name by Dr McQuillan in the early 2000s and then rarely seen — until last year, when a group of volunteers from Wildcare Tasmania surveyed the population in the state's remote south-west.

The group call themselves the Friends of the Pandani Moth.

Jarrah Dale, an ecologist with the Tasmanian Department of Natural Environment (NRE) and the group's president, became captivated by the moth years ago after reading Dr McQuillan's description paper.

His position as a ranger at Mount Field National Park at the time helped feed his curiosity.

"What do you mean there's this moth that just lives in the alpine area and it mostly hops, and its closest relatives are in New Zealand?"

Chew marks on pandani leaves were a clue the elusive moth was there, but it wasn't until years later, when Dr Dale returned to Australia after completing an overseas PhD, that he would finally find the insect.

"I decided, 'Bloody hell. I'm going to meet this moth because I've thought about it for so many years,'" he said.

In October last year, Dr Dale enlisted 30 of his friends, many of them scientists, to travel to the Pandani Grove at Mount Field to find the moth.

Unlike its relatives, the pandani moth is not attracted to light.

On the advice of Dr McQuillan, the group brought white sheets to lay out on the ground, and after the sun had gone down, they physically shook the pandanis to dislodge the moths hiding among the fronds.

After several hours of fruitless shaking and searching in the snow, the group found the first of three moths they would encounter on that expedition.

"They were pretty disgruntled about the whole thing because they probably weren't ready to be out in the snow," Dr Dale said.

Buoyed by its success, the group returned to the area last month to continue gathering valuable genetic samples and baseline data to build a picture of the moth's ecology and population.

Dr McQuillan said he estimated Tasmania has roughly 2,000 native species of moth, a figure similar to the number of native plants on the island.

And yet, hundreds of moth species remain unnamed.

"We, even now, are discovering new species of insects every year."

Dr McQuillan believes Tasmania today is where Britain would have been in the 19th century in regard to its knowledge of native insects.

One way of thinking about it, he said, was to understand that one hectare of Kunanyi/Mount Wellington, near Hobart, had more species and biodiversity than the whole of Antarctica.

Dr McQuillan said a changing climate and increasingly frequent and destructive bushfires meant there was a race to "document these species before they're lost forever".

Many aspects of the pandani moth's life cycle remain unknown, and without long-term population studies, Dr McQuillan says it is not known if its population is declining.

The moth is only found in Tasmania and it lives in the pandani plant, which is endemic to the central, western and south-western regions of the state.

Its larvae feed on the plant and are restricted entirely to living in its dense foliage "skirt", which can cling to the plant for decades after they die-off.

Advances in DNA technology in the 2000s allowed researchers to probe more deeply into the moth's relationship with other species.

Its closest living relative is an Aotearoa/New Zealand species that feeds on a plant unrelated to the pandani.

Dr McQuillan said both belonged to an ancient Gondwanan group of insects that had been in the southern hemisphere for tens of millions of years.

With the assistance of volunteers, government bodies and conservation groups can gather data or undertake ecological monitoring that would be otherwise too difficult or expensive to do alone.

But in the past five years, the number of volunteers has declined.

Wildcare Tasmania, which coordinates a network of volunteers, donors and conservation groups, said the volunteers were slowly coming back after five years of decline, but the long timeline for many conservation projects meant more were needed.

"Without coordination, training, equipment and funding, volunteer enthusiasm and local knowledge can't always translate into lasting outcomes," Wildcare Tasmania chief executive Phillip Laroche said.

"And so, we need to bridge that gap, connecting people, resources and partners, so community are empowered to contribute to the long-term protection of Tasmania."

Dr Dale said the pandani moth surveys have been a success, with the aim now to contribute the group's data to peer reviewed research.

But for the group, the monitoring missions have become much more than purely academic.

"As kids, we liked flipping over rocks and looking at lizards or collecting tadpoles," Dr Dale said.