White spot moth  (Hadena albimacula)

White Spot

Facts

Kingdom Animalia
Phylum Arthropoda
Class Insecta
Order Lepidoptera
Family Noctuidae
Genus Hadena (1)
Size Wingspan: 30 - 39 mm (1)

Status

Classified as Vulnerable in Great Britain (2).

Description

This species is easily recognised by the large white spots on the forewings, referred to by both the common and scientific names (albimacula derives from the Latin 'albico'- to be white and 'macula'- spot). The hindwings are brown in colour, becoming darker towards the edge (3).

Range

Populations of the white spot moth are currently known in Dungeness in Kent, near Gosport in Hampshire, and on the south coast of Devon. Over the last 25 years, the range of the species in Devon has declined to a great extent. Although it could be described as 'abundant' in Dungeness (4), all current populations are vulnerable. The species is known from most European countries (2).

Habitat

Inhabits shingle beaches and calcareous cliffs where the foodplant of the caterpillars, Nottingham catchfly (Silene nutans) is present (2).

Biology

This species is usually single-brooded; the adults are active between mid-May and July, but there is some evidence of a second brood (4). The caterpillars feed on the seed capsules of the Nottingham catchfly (2) between July and August and the overwintering stage is the pupa (1). The foodplant has sticky stems, hence the common name 'catchfly' (5), and once grew in abundance on the walls of Nottingham Castle and the surrounding castle rock (5). It was first given its present name in 1770 (5), and is currently widespread but local and grows on shingle or rocky cliffs with sparse soil (6).

Threats

The white spot moth is limited by the availability of its foodplant, Nottingham catchfly, which is scarce. Recreation by humans, coastal development, coastal defence work and commercial-scale extraction of shingle, gravel and sand have all put this species under pressure (2).

Conservation

The white spot moth is a UK BAP (Biodiversity Action Plan) priority species. The plan aims to maintain the present populations by considering the species with habitat action plans for coastal vegetated shingle and maritime cliffs and slopes. A regular monitoring programme has been proposed, furthermore Dungeness is a candidate SAC (Special Area of Conservation) (2).

Authentication

Information authenticated by David Walker.

Calcareous: Containing free calcium carbonate, chalky.
Pupa: Stage in an insect's development when huge changes occur, which reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
Single-brooded: Also known as ‘univoltine'. Referring to an organism which has just one brood each year.

References

  1. Skinner, B. (1984) Colour Identification Guide to Moths of the British Isles. Viking Press, London.
  2. UK BAP (January, 2002)
    http://www.ukbap.org.uk/ukplans.aspx?ID=346
  3. Walker, D. (2002) Pers. Comm.
  4. Walker, D. (1998) A species profile- White Spot Hadena albimacula. Atropos, 5: 35 - 36.
  5. Brown, C. (1896) History of Nottinghamshire. Elliot Stock, London. Available at:
    http://www.nottshistory.org.uk/Brown1896/flora2.htm
  6. Natural England – The Plant Press (September, 2008)
    http://www.plantpress.com/wildlife/o708-nottinghamcatchfly.php