Lunar yellow underwing moth (Noctua orbona)

The scarce Lunar Yellow Underwing has dark brown forewings but deep yellow hindwings with a broad brownish-black border. There is a black spot on the margin of the forewing (the 'costa') near the apex ⁽²⁾. The moth can suddenly display the hind wings when threatened in order to alarm potential predators ⁽⁴⁾.

Size

Wingspan: 37 - 42 mm ⁽²⁾

Adults of this single-brooded species fly between late June and September, and possibly aestivate during August ⁽¹⁾. Caterpillars are present from October to April and feed at night on fine grasses ⁽¹⁾. The pupal stage occurs underground ⁽³⁾.

This species has undergone a sustained decline but formerly had a wide distribution in the UK. The current stronghold is in the Brecklands of Norfolk and Suffolk ⁽³⁾. It is also currently reported from north east Scotland, and caterpillars have been found in the Wirral (Cheshire) in 2002 ⁽²⁾. Elsewhere it is known from North Africa, Central Asia and the Middle East, and is a local species in Europe, but is absent from the south-west of Spain and Portugal, southern Greece and Ireland ⁽³⁾.

You can view distribution information for this species at the National Biodiversity Network Atlas.

Generally associated with open grassy sites amongst woodland and heathy, sandy or calcareous areas ⁽³⁾.

Classified as Nationally Scarce in Great Britain ⁽³⁾.

Destruction of fine-grass heaths, and sheep grazing and close-mowing of tufted grasses are the major threats facing this species ⁽²⁾.

The Lunar Yellow Underwing moth is a UK Biodiversity Action Plan (UK BAP) priority species. The Species Action Plan aims to maintain the current range of the species. Survey and research has been largely carried out in the Brecks ⁽²⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

The UK Biodiversity Action Plan for this species is available at UK BAP.

There may be further information about this species available via the National Biodiversity Network Atlas.

Further reading on moths:
Leverton, R. (2001) Enjoying Moths. Poyser, London.
Skinner, B (1998) Moths of the British Isles. Viking, London.

Information authenticated by Gerry Haggett.

Aestivation

Period of dormancy occurring in hot, dry periods, analogous to hibernation in winter.

Calcareous

Containing free calcium carbonate, chalky.

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.

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.

1. Skinner, B. (1984) Colour Identification Guide to Moths of the British Isles. Viking Press, London.
2. Haggett, G. (2002) Pers. comm.
3. UK BAP Species Action Plan (January 2002): http://www.ukbap.org.uk
4. Pers. observation from images.