Tiny ice age fly discovered in mountain loch

A tiny fly which is a relic from the ice age has been discovered in a Highland loch.

The National Trust for Scotland team is celebrating the discovery of the rare and threatened Wiedemmania simplex species.

Affectionately known as the Arctic Wave Dancer was found at the Mar Lodge Estate National Nature Reserve.

A search for the species was undertaken by entomologist Iain MacGowan and National Trust staff in July 2024. National Trust for Scotland

They can only develop in cold, deep, and pure water, making the Cairngorms’ high-altitude lochs a suitable home for the species.

During its short adult life span in the summer months, it can be found clinging to the verges of rocks and displaying its unique courtship dance and waterproof abilities.

A search for the species was undertaken by entomologist Iain MacGowan and National Trust staff in July 2024.

They found the Arctic Wave Dancer dancing on the edges of Lochain Uaine and its granite boulders, 950m high in the shadow of Ben Macdui, where it has never been recorded before.

The three lochs in the Cairngorms, two of which are on the conservation charity’s Mar Lodge Estate, are the only known sites for the fly in the UK.

Its next nearest populations are in the arctic regions of Finland, Norway and Russia.

The species was initially rediscovered by Iain MacGowan at Loch Avon in 2018, and in 2020 it was discovered for the first time Loch Etchachan on the Mar Lodge Estate.

Due to the specific cold water temperatures required for the species to thrive, the Arctic Wave Dancer is one of the species most at risk from climate change.

Andrew Painting, conservation officer at the Mar Lodge Estate, said: “The Arctic Wave Dancer lives in about as remote and challenging an environment as you can find in Scotland.

“So finding it at a new site was a wonderful surprise and is a testament to the hard work and skill of dedicated entomologists.

“Our charity is responsible for protecting the nature in our care and the discovery of one of Britain’s rarest species at Mar Lodge Estate is evidence of nature’s resilience and the importance of our conservation work.

“Every species we protect is a step towards safeguarding Scotland’s nature, beauty and heritage for everyone.”

Mr MacGowan said: “Although it’s small, this fly is of enormous importance to the Cairngorms and the wider British Isles.

“Living on only a few of the high-altitude lochs, it is on the front line when it comes to meeting the challenge of climate change.

“Finding it at its highest-level site, 950m at Lochan Uaine, will hopefully ensure that the populations will be better able to withstand the effects of a warming climate.

“We must continue to monitor this iconic species and carry out further surveys of other potential sites.”