New native British beetle found in ancient Scottish forests

28 September 2017

The male and female versions of Pogonocherus caroli

The male (left) and female (right) versions of Pogonocherus caroli, a longhorn beetle

A chemist who collects insects as a pastime has spotted what generations of British entomologists have missed: a native British beetle, living in ancient Scottish pine forests.

The beetle, Pogonocherus caroli, is only known from a handful of other sites in Europe. The discovery considerably enlarges the known range of this rare insect.

Museum beetle curator Max Barclay, who co-authored the scientific paper on the find, says, 'To find it in the British Isles is very surprising. We have a history of entomology that goes back 200-300 years, so it's odd that it has been overlooked for such a long time.'

New eyes on an ancient forest

Dr Martin Rejzek, a research assistant in biological chemistry at the John Innes Centre in Norwich, was investigating the Highland forests when he saw the beetle larvae on dead pine branches. He took them home, and when they hatched he identified them as P. caroli.

The adult beetles hatch in late summer or autumn, which according to Barclay gives a clue as to why they haven't been spotted before.

'The beetles are around in the autumn and winter but most entomologists who are collecting in Scotland are doing so in June and July. So the beetles are active when the scientists aren't.'

The Black Wood of Rannoch

The Black Wood of Rannoch features a range of native trees, including Scots pine, silver birch, rowan and alder © Richard Webb licensed under CC BY-SA 2.0 via Geograph
 

The forests where the beetles were found, such as the Black Wood of Rannoch, are remnants of the great Caledonian Forest, which once covered most of the Highlands.

The beetle has specific habitat requirements - so its discovery puts the biodiversity seal of approval on these forests, says Barclay.

'These forests are very old and have been there since the glaciers retreated after the end of the last Ice Age.

'They are famous localities for nature, and the animals and plants of the forests are in some ways unique. It's the kind of place where you still find Scottish wildcats and golden eagles. These are not animals that respond well to human alteration of their habitat.'

Beetles from the A A Allen collection

A tray of British beetles kept by the Museum, part of the A A Allen collection
 

Discovering British beetles

There are about 4,000 native species of beetle in the British Isles but only rarely is a new native species discovered.

Were the beetle a recent newcomer, it would have likely been found spreading through pine trees in southern Britain, rather than restricted to sites in ancient northern forests.

'This is an example of something that has probably always been here and we have overlooked it,' says Barclay.

'That's very uncommon. I can think of two or three examples in my career of somebody finding a British native beetle that has been overlooked by generations of our entomologists and conservationists.'

The collecting bug

Dr Rejzek's discovery is a reminder of the importance of protecting ancient forests as refuges for rare species. It also emphasises the importance of collecting.

'The discoverer collects insects as a hobby,' says Barclay, 'but if it wasn't for expert amateurs like him – like Charles Darwin and the ones who built up the Museum's collections – we would know much less about the biodiversity of this country and the world.

'It is brilliant to know that this rare species exists in Britain, and pure good fortune for science and conservation that Dr Rejzek had the right knowledge, and was in the right place at the right time, to discover it.'

  • By James McNish

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