‘Body snatcher’ discovered

An American master’s student and his partner exploring a remote area of Otago discovered a new species in 2016. Zachary Tobias and his then fiance, now wife, Brenah Hearne were searching for worms in streams around the Rock and Pillar Range, near Middlemarch, in March 2016.

Tobias’ PhD field now is biological oceanography but the couple found a new species of hairworm from the genus Gordionus, known as body snatchers for their parasitic behaviour.

Its eggs are laid in water and they hatch into larvae that infects a host, usually a stonefly or a mayfly nymph. When the host metamorphoses and exits the water, it transports the parasite on to land.

There the first host is eaten by the definitive host – a cricket or a grasshopper.

Once they reach adulthood, hairworms do not need a host for survival and become free-living. But they are unable to reproduce on land and return to parasitism for transport back to water.

They find and infect an invertebrate host, which they manipulate to enter water. The adult worm then wriggles out and looks for a mate. On finding a mate, they form a mating knot known as a gordian knot.

Tobias and Hearne collected parasites all summer and found this specimen initially didn’t seem different from the others. Later, the genetic data and confirmation from Andreas Schmidt-Rhaesa, the worldwide expert on hairworm taxonomy, confirmed the find.

‘‘I never thought I would find an undescribed species,’’ Tobias said. The species was named Gordionus ma¯ ori, ‘‘out of respect for the indigenous people of Aotearoa-New Zealand and their strong legacy of ecological stewardship’’, Tobias said.

The couple found the worm two years ago and the species description was published in the New Zealand Journal of Zoology earlier this year.

‘‘Not many people give parasites a second thought, or if they do they generally think of them in a negative light.

‘‘However, parasites are an integral part of ecosystems and can have far reaching impacts beyond just those on their hosts.’’

Tobias said his partner ‘‘is up for anything’’.

‘‘This was pretty tame compared to my other masters project, which consisted of pulling apart rotting heaps of kelp on the beach looking for sand hoppers and the parasites inside them.’’

The holotype – a specimen used to identify and designate a species – is now kept at the Otago Museum.

Big bird brains

Birds that live on oceanic islands formed by seismic or volcanic activity – such as New Zealand and the Galapagos – have larger brains than their mainland relatives, according to an international study.

The use of tools by kea, the New Caledonian crow, and the Galapagos woodpecker finch led researchers to think that island life leads to the evolution of advanced cognitive abilities (and therefore bigger brains).

The researchers compared the brain size of almost 2000 species of bird using more than 11,500 specimens from collections, and say their findings mean the birds evolved these big brains on the islands.

Trees have aqueducts

Pandanus trees on Lord Howe Island have evolved an elaborate rainwater harvesting system akin to modern aqueducts, allowing them to supply their roots with water before they reach the ground, according to New Zealand scientists.

The trees can grow up to 15m high and are propped up for support by these stilt-like roots.

Because the roots can take years to reach the ground as the tree grows – preventing the tree from drawing water from the ground – the tree uses gutter-like leaves and a series of channels along the tree to capture and courier water to the plant.

‘‘Not many people give parasites a second thought, or if they do they generally think of them in a negative light.’’ Zachary Tobias, left