Slender Scotch burnet (Zygaena loti scotica)

GenusZygaena (1)
SizeAdult wingspan: 24-30 mm (2)

Classified as Rare in Britain (3).

The Slender Scotch Burnet is a striking red and black moth that can be distinguished from other burnet moths by its hairy abdomen, the presence of a kidney-shaped black mark in the outer area of the forewing and the narrower black border on the hindwings (3) (2). Burnet caterpillars are typically stout and strongly patterned with green yellow and black (4). In this species they are dark grey-green, with indistinct, small yellow and black spots along the side (2).

Although Zygaena loti is found throughout central Europe, the subspeciesscotica is endemic to Scotland (5). It has an extremely restricted distribution in Scotland, and is classified as rare. It is at currently found only on the Hebridean islands of Mull and Ulva (3). Colonies in the north of Mull and on the mainland at Morven (Argyllshire) have become extinct (5) (3).

Inhabits south or south-west facing grassy banks and low cliffs close to the sea where the larval foodplant bird’s foot trefoil (Lotus corniculatus) is found (1) (5). The short vegetation on these slopes is maintained by grazing and erosion (5).

The moth is single-brooded. Adults are present from June to early July. They fly during the day in sunshine and visit the flowers of the foodplant, bird’s foot trefoil. The caterpillars are present from August to early may of the following year (3). They spend the winter in diapause and some caterpillars re-enter diapause immediately after emerging. It is unclear how many successive years caterpillars may do this, and it is thought that this phenomenon may partly explain why the populations of adult moths fluctuate greatly from year to year (5).

In some areas a lack of grazing may lead to vegetation succession and eventually to bracken growth, which removes suitable habitat for this species (2). Other threats include the increasing isolation of remaining colonies and collecting of adults and caterpillars (5) (2).

The Slender Scotch Burnet is listed as a priority species under the UK Biodiversity Action Plan, and a Species Action Plan has been produced to coordinate conservation efforts aimed at this moth (5). One of the aims of the Action Plan is to maintain all current known populations of the Slender Scotch Burnet. Targeted habitat management is already in place in some areas. Most of the current populations occur within Sites of Special Scientific Interest (SSSIs), and National Trust for Scotland owned land, and so the needs of the species are considered at these sites (5). Nevertheless, it is continuing to decline (2).

Information authenticated by Dr Mark Young of Aberdeen University with the support of the British Ecological Society

  1. NBN Species Dictionary. (Feb 2003). Available on-line from: /
  2. Young, M (2004) Pers. comm.
  3. Skinner, B. (1984) Colour identification guide to the moths of the British Isles. Penguin Books, Harmondsworth
  4. Carter, D. J. (1986) A field guide to caterpillars of butterflies and moths in Britain and Europe. Collins, London.
  5. UK BAP Species Action Plan for Zygaena loti scotica. (November 2003):