When ornithologist Greg Kerr found and photographed a swallowtail butterfly by the side of a former logging track whilst working on the Fijian island of Vanua Levu in 2017, he didn’t expect to have discovered a species new to science – but it turns out that he did just that.
The new species, now officially named as Papilio natewa, has two sword-like tails projecting out of the back of each wing with elaborate, winding black and white stripes adorning the tops, embellished further down with black dots, housing flecks of blue and yellow.
“The discovery of a new swallowtail is hard to believe,” says John Tennent, a scientific associate at the Natural History Museum in London.
“The new swallowtail is a big butterfly, recognizable from a distance. There were previously only two swallowtail butterflies known from the region, endemic to Fiji and Samoa. Both are large but dull in appearance. To find a third as large, colourful and unusual, with its long, sword-like tails, really is remarkable.”
Lepidopterists were puzzled by the Kerr’s photo of the species when it was initially shared, as its markings didn’t fit with what was already documented on butterfly diversity in Fiji, or in the wider region.
It wasn’t until earlier this year that Tennent confirmed the new species during a fieldtrip to Fiji with his colleagues after the first sighting was made, officially declaring it a new scientific find.
P.natewa is 8cm across and is said to have remained undiscovered for so long due to its habitat, as it spends most of its life inside the forest canopy at heights above 250m.
The new species made its brief first appearance at the side of a former logging track, and the following sightings were so irregular it took a couple of months before its true habitat could be established.
After this, observations were underway to understand the behaviour, habitat and ecology of the new species.
The natural history of P. natewa – named after the peninsula where it was found, is still shrouded in mystery, with much more research needed to understand the life cycle of this elusive species.
“The early stages of its life and even its host plant remain unknown. Figuring that out will be a big job for someone in the future,” says Tennent.
It is as yet unclear how the butterfly came to evolve on the island, although researchers managed to collect several specimens, which that are now in the Fiji National Insect Collection.
Genetic analysis has revealed a connection to Papilio anactus, a species of swallowtail butterfly found in eastern Australia.