This is the fourth post in a six part blog series about rare insects in the Cairngorms. A new project launched this year to save six endangered invertebrates in the north of Scotland and project officer Gabrielle Flinn will take a closer look at one of these species each month. This time, it's the turn of the dark bordered beauty moth. The Rare Invertebrates in the Cairngorms project is a partnership involving RSPB Scotland, the Cairngorms National Park Authority (CNPA), Buglife Scotland, Butterfly Conservation Scotland and Scottish Natural Heritage (SNH).

Aspen suckers graze our knees and ankles as Pete Moore from RSPB Scotland Insh Marshes reserve explains we are about to walk through the most important site for the moth, dark bordered beauty (Epione vespertaria), in Scotland.

Just as our eyes scan the low growing young Aspen, the moth’s food plant, a male makes a timely appearance, fluttering up from the vegetation to say hello before quickly flying back to the safety of the undergrowth. The moth is well camouflaged, looking very much like a yellowing leaf, and is at first hard to spot.

Once the Rare Invertebrates in the Cairngorms (RIC) volunteers spot the individual, however, there is a ripple of excitement and cameras come out to capture this moment of entomological elation. 

RIC volunteers observe a moth in wonder during DBB training

The dark bordered beauty, is named literally (as is the habit of lepidopterists), and bears a thick dark border along the edge of its yellow-orange wings whilst also being strikingly beautiful. In Scotland, the caterpillars feed on the leaves of young aspen suckers whilst those south of the border have a preference for creeping willow.

Caterpillars hatch in May after overwintering as eggs, pupate into adults in July and can be found flying into August. Males, who are darker in appearance are the most likely to be seen as they are more mobile than the females who are more likely to stay very close to where they hatch.

Due to a loss of native woodland, the increase of grazers and a reduction in diversity within forests (meaning there are less open glades and trees which are all of a similar age) over the decades, this moth has suffered as the niche it has evolved to occupy has dramatically reduced.

As part of the RIC project, we will be trying to find new sites of suckering aspen were this moth may have not yet been discovered and we will be working with land owners to try and help create better habitat for the moth across the National Park.

Enjoy this blog? Check out the previous three in the series on the northern silver stilleto fly, shining guest ant and Kentish glory moth.