In Cornwall’s upland meadows, the rare Scotch Argus meets its late-summer ally, Devil’s-bit Scabious. Here, dark wings over purple flowerheads mark a fleeting partnership — one sustained by nectar, fine grasses for larvae, and the linked meadow-heath networks these landscapes depend on.
On a warm August afternoon in Cornwall’s upland meadows, the air is rich with the scent of grass and the low hum of insects. A movement close to the ground catches the eye — a butterfly, dark as peat yet edged with fire, drifting low over the grass. When it settles, the sunlight reveals orange bands and neat eyespots along its wings: the Scotch Argus (Erebia aethiops), a rare visitor to Cornish soil.
With a wingspan of 35 to 40 millimetres, the Scotch Argus is neither large nor brightly coloured, yet its markings hold a quiet richness. The deep chocolate-brown wings are bordered by a warm amber wash, interrupted by small black eyespots with pale centres. Males patrol restlessly over the meadow, flying low and purposeful, while females prefer to bask, wings open, drinking in the sun’s warmth.
The UK stronghold of this butterfly lies in Scotland and parts of northern England. In Cornwall, it is now considered either absent as a breeding species or present only through occasional dispersal from elsewhere. Historic records cluster around cool, damp upland meadows and moorland fringes — places like the edges of Bodmin Moor — where tall grasses, late-summer flowers, and gentle slopes create the right blend of shelter, humidity, and nectar.
In the same meadows, another late-summer specialist comes into its own. Devil’s-bit Scabious (Succisa pratensis) stands tall among the grasses, each stem topped with a lilac-blue pincushion of flowers. Blooming from July into October, it reaches its peak just as the Scotch Argus takes to the wing. The plant thrives in damp, neutral to acidic soils — the very conditions found in Cornwall’s marshy upland pastures and heath margins.
For the Scotch Argus, Devil’s-bit Scabious is a vital adult nectar source, not a larval foodplant. The caterpillars feed on fine-leaved grasses found in traditional, lightly grazed meadows. Yet the nectar of Scabious fuels the short-lived adults during their mating flights, sustains the energy needed for egg-laying, and draws butterflies into loose congregations on sunny days. Where Scabious grows in abundance, the meadows hum with pollinators — bees, hoverflies, and other butterflies — creating a shared stage for late-summer life.
This seasonal harmony is brief. By early September, days shorten, weather turns, and both butterfly and flower begin to fade. In a healthy upland meadow, the Scotch Argus emerges just as the Scabious reaches full bloom, ensuring the adults have an energy-rich nectar source during their short flight period. Females lay eggs among grasses in sunny, sheltered spots — often in the same traditional meadow systems where Scabious thrives, even though the plant plays no role in the larval diet.
In Cornwall’s fragmented upland landscapes, this synchrony is fragile. The loss of meadow habitat, drainage of damp pastures, or overgrazing can reduce Scabious stands and the grassy swards needed for caterpillars. Without connected meadows and heathland fringes, small or reintroduced populations could not persist; linked habitat systems are essential for any chance of maintaining or re-establishing this butterfly here.
A Scotch Argus site in late summer is a mosaic. Tall, tussocky grasses ripple in the breeze. Heathland edges carry the muted purples of ling heather, while damp hollows glisten with rushes and sedges. Scattered among them are drifts of Devil’s-bit Scabious, their purple heads nodding in the light wind. These conditions are shaped by low-intensity grazing, traditional hay-cutting, and the absence of heavy improvement — land that has been allowed to keep its texture and diversity.
In Cornwall, such places are now rare. The best examples cling to the fringes of moorland and in reserves where conservation management mimics traditional practices. Here, microclimates form in sheltered dips or along the backs of hedgebanks, holding moisture and providing calm air for low-flying butterflies.
Longer summers might seem a gift to late-flying species, potentially extending the flowering period of Devil’s-bit Scabious and the flight window of the Scotch Argus. Yet shifts in timing can also bring mismatches: if the flowers peak too early or the butterflies emerge too late, the partnership falters. Severe drought, sudden storms, or untimely mowing can strip the meadow of nectar just when it is most needed.
Climate change, land use pressures, and habitat fragmentation all compound the risk. For a butterfly already scarce in Cornwall, maintaining the seasonal overlap with its key nectar plant — and the continuity of connected upland meadow systems — will be vital.
Imagine standing at the edge of an upland meadow in late August. The sun is warm but softened by high cloud, the ground uneven underfoot with tussocks and flower clumps. Ahead, a Scotch Argus flits low over the grass, then settles on a Scabious head. Its dark wings open to reveal the amber arcs, the eyespots, the quiet perfection of a late-summer insect in its element. The flower sways gently, and for a moment, butterfly and bloom are held together in balance — a fleeting union that depends on the continued health of this rare habitat.
Where to see Devil’s-bit Scabious and look for the Scotch Argus in late summer
Best Time
Late July through August, on still, sunny days. Devil’s-bit Scabious is at peak bloom, and if the Scotch Argus is present, this is when you’re most likely to see it.
Current Status in Cornwall
The UK stronghold for the Scotch Argus is in Scotland and parts of northern England. Cornish records are from isolated historical populations or occasional dispersal, and it is not thought to be a regular breeder here today.
Possible Sites in Cornwall
What to Look For
Conservation Note
Linked meadow and heathland systems are essential for any viable or reintroduced Scotch Argus population in Cornwall, supporting both larval foodplants (grasses) and adult nectar sources.
Walking Notes
Paths can be uneven or boggy after rain. Wear sturdy shoes, take care on moorland slopes, and keep to paths where livestock is present. Dogs should be kept under close control around grazing animals and ground-nesting birds.
