Exciting discovery of rare moth presents poser for experts
A rare species of moth that is increasingly hard to find in its usual central Highlands locations has been found on a Lowland Raised bog in Fife.
Normally associated with dry moorland habitat where it can find its main food plant, Bearberry, the Small Dark Yellow Underwing (SDYU) is only found in the UK at sites in the Cairngorms and Highland Perthshire, with one outlying location in Easter Ross.
Never before recorded south of Angus, it was discovered on an area of land that Forestry and Land Scotland is restoring to bog habitat.
Forestry and Land Scotland Environment manager, Colin Edwards, who made the discovery, said;
“I was visiting the site on a day off looking for a different species altogether so to have found a Small Dark Yellow Underwing was quite a surprise, especially a location where you would never expect to find it.
“Even at traditional sites it’s difficult to find. In full sun they are very active and fly extremely fast so they are difficult to see and in duller weather they will often rest on fence posts for hours, so you have to go looking there for them.
“Now we know it’s there, we’re reviewing our plans with a view to enhancing the habitat for this species of moth.”
SDYU is a day-flying moth that has dark upperwings with a white kidney shaped mark in the centre, and yellow underwings. It’s wingspan is only 24-28mm.
Appearing on the Scottish Biodiversity List, this species of moth is included in the ‘highest priority and threat’ category in Butterfly Conservation Scotland’s Conservation Strategy and is prioritised within Butterfly Conservation’s 2021-2026 Strategy.
Tom Prescott, Senior Conservation Officer with Butterfly Conservation Scotland, said;
“This sighting is remarkable. This species seems to have become less common at former occupied sites, despite its food plant being present and yet here it is, over 50km away from its usual haunts, at a location where its main food plant isn’t found.
“One possibility is that it is feeding on Bog Bilberry, as its mainland European cousins do. The bog Bilberry grows in damper conditions than Bearberry, and if the moths are now feeding on this plant it could mean that they are at many more sites across Scotland.
“It’s great news because it could mean that the decline has not been as precipitous as we thought and that we might just have been looking in the wrong places.
“However, we’re not jumping to any conclusions and will be looking to carry out more research on the basis of this discovery.
“Together with our UK colleagues, we are working to halve the number of the UK’s threatened species of butterflies and moths and the Small Dark Yellow Underwing is one of the 71 species that we are focussing on. That makes this find is all the more exciting!”
An analysis in 2014 found that SDYU had not been seen since 2000 at almost two thirds of all formerly known sites.
It has also performed far worse than other specialist Scottish moths that share similar habitat and/or diurnal habits.
Notes to editors
Forestry and Land Scotland (FLS) manages forests and land owned by Scottish Ministers in a way that supports and enables economically sustainable forestry; conserves and enhances the environment; delivers benefits for people and nature; and supports Scottish Ministers in their stewardship of Scotland's national forests and land.