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Slender Scotch burnet moth

What action is going on for this species?

The following will give you information on what work has been taking place through the Species Action Framework:

Species background

The Slender Scotch Burnet external site   moth (Zygaena loti scotica) is a red and black day-flying moth with a wingspan of 25-30 mm. Larvae are dark grey green, with indistinct yellow and black spots along the side.

Why is this on the Species Action List?

The slender Scotch burnet moth Zygaena loti scotica meets criterion 1a of the Species Action Framework, as a species for conservation action. 

It has shown a marked decline in the UK, where it is restricted to Scotland. It is a UKBAP Priority (sub) Species, and is included on the Scottish Biodiversity List.

Zygaena loti is widespread in central Europe, but the subspecies scotica is presumed to be endemic to Scotland.

Habitat, distribution and abundance

The slender Scotch burnet inhabits low cliffs and grassy banks on sunny, south-facing coasts where the larval foodplant bird's-foot trefoil grows in open swards. 

It has a narrow distribution in the UK, occurring only in Argyll at eight sites within three 10-km squares, on the islands of Mull and Ulva.

General ecology

Adult males are seen flying around in good weather, congregating on flowers such as milkworts. Females tend to perch and take nectar from the larval food plant, bird's-foot trefoil. The larvae bask near the food plant in spots open to the sun such as stones, bare soil or moss cushions. Larvae are absent from tall grass swards even though the food plant is present. 

All breeding sites are prone to rock and soil slides, which maintain the vegetation in early successional stages. Colonies depend on the periodic creation of small patches of suitable habitat by grazing and natural erosion. Nonetheless, colonization is limited because the adults are largely sedentary; few stray beyond the immediate boundaries of colonies.

History of decline, contributory factors and current threats

The slender Scotch burnet is now restricted to its few island colonies in Argyll, having become extinct on the mainland.  The main threats to this moth are inappropriate grazing levels, afforestation and isolation of colonies.  Due to under-grazing, bracken invasion has damaged several sites.  Encroachment from Cotoneaster species is also a problem.

The 'Species Lead' at Scottish Natural Heritage

brigid.primrose@snh.gov.uk   Tel 01463 725000