Argent and sable moth (Rheumaptera hastata)
| Kingdom | Animalia |
|---|---|
| Phylum | Arthropoda |
| Class | Insecta |
| Order | Lepidoptera |
| Family | Geometridae |
| Genus | Rheumaptera (1) |
| Size | Wingspan: 3.4- 3.8 cm (1) |
Classified as Nationally Scarce in Great Britain (2).
The common name 'Argent and Sable' which was given to this species in 1778 refers to the colour of the moth. Argent is a silvery-white colour and sable is black, both terms especially used in heraldry (3). Both the fore- and hindwings are white in colour with variable black markings (4). The caterpillar has a stumpy appearance, and is dark green in colour with a black head and a black line passing along the length of the back (4).
This moth has a wide distribution in England, but now occurs in scattered colonies following a decline throughout most of the range (2). In Scotland it is found in the Hebrides, the north-west and the southern uplands (3). It also has a wide distribution in Europe and is found in North America, Japan, China, Korea, Siberia and Amur (2).
Inhabits open un-grazed bogs and moors (3) and is also found in woodlands with regenerating birches (2).
Adults of this single-brooded moth fly during the day in June and early July (1). Populations occurring on moorland tend to fly later in the season (3), and show a preference for warm sunny weather (1). The caterpillars are present in July and August and live inside birch (Betula) or bog myrtle (Myrica gale) leaves, located at the tips of branches, which they spin together and feed on from inside. The pupal stage overwinters (1) either amongst moss or in spun leaves (3).
The Argent and Sable has suffered due to the decline in traditional management of woodlands such as coppicing. This has resulted in a decrease in young regenerating birch in rides and at the periphery of woodlands. Intensive sheep grazing on moorland has also affected birch regeneration (2).
The Species Action Plan aims to maintain all current populations with enhancement by the year 2010 (2). A number of populations occur within Sites of Special Scientific Interest (SSSIs), and three key areas where the species is present have been targeted by The Forestry Commission's Coppice for Butterflies Challenge. Measures taken to conserve this species will be likely to aid other moth species that inhabit coppiced woodlands such as the Orange Upperwing (Jodia croceago), the Clay Fan-foot (Paracolax tristalis) and the Drab Looper (Minoa murinata) (2).
Further reading on moths:
Leverton, R. (2001) Enjoying Moths. Poyser, London.
Skinner, B. (1984) Moths of the British Isles. Penguin Books, Harmondsworth
Information authenticated by Sean Clancy.
- Coppicing: traditional form of woodland management in which trees are cut close to the base of the trunk. Re-growth occurs in the form of many thin poles. Woodlands are cut in this way on rotation, producing a mosaic of different stages of re-growth.
- Pupal stage: stage in 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.
- Rides: often the footpaths and access tracks which run through and divide blocks of trees in woodland. Many rides contain a mixture of rich flora and structure, and provide different habitat conditions for a range of wildlife.
- 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.
- Skinner, B. (1984) Colour Identification Guide to Moths of the British Isles. Viking Press, London.
- UK BAP Species Action Plan (December 2001): http://www.ukbap.org.uk
- Stirling Government (December 2001): http://www.stirling.gov.uk/countryside/
- South, R. (1961) The moths of the British Isles. Frederick Warne & Co. Ltd., London.