New Forest burnet  (Zygaena viciae argyllensis)

Classified as Endangered in Britain and fully protected in the UK under Schedule 5 of the Wildlife and Countryside Act, 1981 (3).

The New Forest Burnet was first discovered in 1869 in the New Forest (2). The endemicsubspecies (Zygaena viciae ytenensis) was last seen in 1927 and is now sadly extinct. The subspecies Zygaena viciae argyllensis, which is also endemic, was found in western Argyllshire in 1963. It is a striking crimson and red moth, that differs to Z. v. ytenensis in that it has broader and darker forewings and a thicker border on the hindwings. Furthermore, the thorax and abdomen are more hairy (4). The caterpillars are grass-green in colour, with small yellow flecks and black dots along the sides (2).

This subspecies is only found in a single site in western Argyll, Scotland (3).

Found in fairly long grassland where the foodplants meadow vetchling (Lathyrus pratensis) and bird’s foot trefoil (Lotus corniculatus) grow (3).

Adults of this single-brooded species fly in sunshine throughout July (2), when the eggs are laid. The caterpillars resulting form this brood are present from August to May of the following year, and feed on meadow vetchling and bird’s foot trefoil. They over-winter once or twice as a caterpillar before undergoing pupation(4).

Potential threats facing this endangered moth include sheep grazing and collecting of adults and caterpillars. The fact that just a single colony exists at present makes this subspecies inherently vulnerable to chance events, such as storms and accidental habitat damage, for example (3).

The New Forest 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 (3). One of the aims of the Action Plan was to increase the current size of the population to over 250 adults. This was achieved by 1999. The colony occurs within a Site of Special Scientific Interest (SSSI) where the needs of the moth are considered in the management of the site by Scottish Natural Heritage. Furthermore, the site has been fenced to keep sheep out of the area, and the colony is monitored regularly so that any changes can be detected (3).

Information authenticated by Dr Mark Young of Aberdeen University
http://www.abdn.ac.uk/biologicalsci/ with the support of the British Ecological Society
http://www.britishecologicalsociety.org/

• Abdomen: in arthropods (crustaceans, insects and arachnids) the abdomen is the hind region of the body, which is usually segmented to a degree (but not visibly in most spiders). In crustacea (e.g. crabs) some of the limbs attach to the abdomen; in insects the limbs are attached to the thorax (the part of the body nearest to the head) and not the abdomen. In vertebrates the abdomen is the part of the body that contains the internal organs (except the heart and lungs).
• Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
• Pupation: the process of becoming a pupa, the stage of an insect’s development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
• Single-brooded: (Also known as ‘univoltine’). Insect life cycle that takes 12 months to be complete, and involves a single generation. The egg, larva, pupa or adult over winters as a dormant stage.
• Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
• Thorax: part of the body located near the head in animals. In insects, the three segments between the head and the abdomen, each of which has a pair of legs.

1. NBN Species Dictionary. (Feb 2003). Available on-line from: http://nbn.nhm.ac.uk/nhm/
2. Young, M (2004) Pers. comm.
3. UK BAP Species Action Plan for Zygaena viciae argyllensis. (November 2003): www.ukbap.org.uk
4. Skinner, B. (1984) Colour identification guide to the moths of the British Isles. Penguin Books, Harmondsworth.