Scotch Argus Erebia aethiops (Esper 1777) )
Family: Nymphalidae, subgroup Satyrinae (The Browns)
Photos by Iain H Leach
The Scotch Argus looks similar to Meadow Brown, but is darker to the point of being almost black when fresh. Also there are more spots on the upper wings and a figure of eight eyespot on the forewing in closed wing view.
Males are blacker and females are browner. The number of eyespots on the upperwings is variable but usually three in males and four in females.
This butterfly tends to fly only when the sun is shining, but can be active as soon as the sun rises in the early morning. On warmer days males may sometimes fly in duller conditions.
The English population belongs to the subspecies aethiops Esper, the Scottish population to subspecies Caledonia Verity. Scottish specimens are noticeably smaller though it is quite a variable species with over 30 varieties described.
This species prefers higher areas and covers most of Europe and Asia. It is also found in Scotland. In England there are only two known colonies, both in Cumbria; at Arnside Knott, (National Trust) and Smardale near Kirkby Stephen (Cumbrian Wildlife Trust).
The eggs are laid singly on blades of grass, which are either part of the foodplant or near it and the greenish-yellow larvae hatch after two to three weeks by chewing out a lid on the top of their egg, leaving just enough to act as a hinge so they can push it up and crawl out. Young larvae feed by day and night and rest at the base of grass clumps when not active. They hibernate in a similar location, usually in the second instar, around October. It is thought that less than half survive winter, possibly due to a mould. The larvae begin to feed again in March, though mainly at night.
Overall this is a species which is poorly understood.
Butterfly Conservation priority: Low
European status: Near threatened
With thanks to the Butterflies of Yorkshire edited by Howard M Frost and Dr Andy Suggitt
Catherine Jones 10/11/20