SCIENTISTS working in the Highlands are set to uncover the secrets of one the UK’s most endangered bumblebees, amid fears the species may disappear entirely in a matter of decades.

The great yellow bumblebee was once common across the UK, but there are now only five known populations remaining as its habitats have gradually disappeared due to intensive farming.

On the British mainland the species is only found in Caithness and north west Sutherland, with the three other colonies in Orkney and the Inner and Outer Hebrides.

Until now, conservationists worried about the future of the species have been unable to tell exactly how low the populations have become, partly due to the remoteness of its remaining habitats.

But a new two-year project launching next month led by the Bumblebee Conservation Trust is aiming to answer this crucial question as the first step to securing the great yellow’s future. Backed by funding from Scottish Natural Heritage and the Heritage Lottery Fund, the project will involve a “bee census” and DNA testing to establish the sustainability of the remaining gene pool.

The Trust said while the species was unlikely to disappear within a few years, it may have “just decades” left due to the tiny number of bees left in the harsh environment of the Highlands.

One of 25 species of bumblebee in the UK, the distribution of the great yellow has declined by 80 per cent since 1900, making it one of the rarest in the country.

“They are very distinctive and very beautiful. There’s nothing else really that looks like them,” said Katy Malone, the Trust’s Scottish conservation officer, who will be leading the study.

“I think it should be one of those iconic species people think of when they think of the Scottish Highlands. Wildcats, red deer, red squirrels – and great yellow bumblebees.”

The number of great yellows remaining in the UK is currently unknown.

She added that the species was literally “pushed to the edge” of the UK over the decades as its preferred habitats disappeared and were replaced by farmed fields.

“It’s a specialist of open meadow habitat and flower-rich open areas,” she said. “Those are exactly the type of habitats that have been disappearing from our countryside, but which are still found on outlying islands and right up on the far north coast of Scotland, as the land is far less intensively managed.”

So far the charity has focused on helping local communities in the Highlands record great yellows in their areas and manage their habitats, but the low human populations have made this difficult.

As well as counting the bees, the forthcoming study will also seek to unlock their secrets by studying what attracts them to certain habitats, so similar ones can recreated elsewhere.

The charity also plans to run “bumblebee identification workshops” to teach volunteers how to spot great yellows and encourage tourists to help with research as they explore the Highlands and Islands.