Northern Ireland's Priority Species

Xanthorhoe ferrugata – dark-barred twin-spot carpet

 
Xanthorhoe ferrugata
Click on map to open large map in new window

Xanthorhoe ferrugata (Clerck, 1759)
Family: Geometridae

A small butterfly-like moth with a distinctive dark central cross band across the pale grey forewings. It occurs in two generations, late April to mid June and again from late June to September. A Northern Ireland Priority Species because of major declines detected elsewhere in the UK. At present such data does not exist for Northern Ireland.

In brief

  • This is a relatively widespread moth found in a wide range of habitats including gardens
  • It has two generations on the wing late April to mid-June and again from late June to September
  • Occurs in all counties but most commonly across the southern half of Northern Ireland
  • It is attracted to light and flies from dusk
  • It is a Northern Ireland Priority Species because of declines detected in other parts of the UK where it has undergone a 83% decline over a 25 year period. There is no evidence as yet that the species has exhibited a similar decline in Northern Ireland but as we are part of the UK it has been included on the Priority List

Species description
A member of the Geometridae, it can be described as a member of this “butterfly-like” group of moths. It normally rests with its pale grey wings open revealing a dark central cross-band. There are two forms of this moth only differing in the colour of the cross-band. The most common form has a blackish-grey band whilst the reddish-brown banded form is much less common. There is a small notch in the back edge of the central band near the costa.

Life cycle
The caterpillar feeds on various herbaceous plants including docks, bedstraws and ground-ivy from June to late August and over-winters as a pupa amongst leaf debris.

Similar species
The dark common form is quite distinctive but the uncommon reddish-brown form can be difficult to distinguish from the Red Twin-spot Carpet. The diagnostic feature is the small notch in the central band which is absent on the Red Twin-spot Carpet.

How to see this species
Can be found in a wide variety of habitats including bogs, fens, hedgerows and suburban gardens. Flies from dusk and comes to light but can be disturbed from bushes and vegetation during the day. Has been recorded in all counties but tends to be more frequent in the south of the province, although it has been recorded from Rathlin Island.

Current status
Can be found in a wide variety of habitats including bogs, fens, hedgerows and suburban gardens. Flies from dusk and comes to light but can be disturbed from bushes and vegetation during the day. Has been recorded in all counties but tends to be more frequent in the south of the province, although it has been recorded from Rathlin Island.

Why is this species a priority in Northern Ireland?

  • Listed as a UK Priority Species and therefore on the Northern Ireland Priority List by default
  • Rapid decline (83% over 25 years 1968-2002) assessed using Rothamstead trap data

Threats/Causes of decline
It is thought to be declining in the UK as a result of many factors, including habitat change, pollution and the use of pesticides.

Conservation of this species

Current action

  • In Northern Ireland there are no specific actions proposed for this species. General management for Biodiversity such as leaving weedy margins on roadsides, woodland rides and in gardens will help maintain the species

Proposed objectives/actions

  • Occurs on many ASSIs
  • Increase Rothamstead Trap network to gather data on status
  • Encourage submission of records to the Moth recorder

What you can do

  • Report all moth sightings to the Moth Recorder for Northern Ireland, Andrew Crory, andrew.crory@gmail.com or use the Butterfly Conservation Northern Ireland (BCNI) sightings web page at http://www.bcni.org.uk/submitsighting.php. The BCNI database is managed by CEDaR and these records will then be used to update the Butterflies and Moths of Northern Ireland website.
  • Join Butterfly Conservation. Butterflies and Moths are in serious decline — with your support Butterfly Conservation can take action to reverse this.

Further information

Links
The Butterflies and Moths of Northern Ireland

UK Moths Website with an up-to-date distribution map

The state of Britain's moths - an explanation as to how declines have been calculated

Background information on the Rothamstead Trap Surveys

Literature
Baynes, E.S.A. (1964). A revised catalogue of Irish macrolepidoptera (Butterflies and Moths). EW Classey, Hampton, Middlesex.
Porter J. (1997). The colour identification guide to caterpillars of the British Isles. Viking, London.
Skinner, B. (2009). 3rd revised and updated edition. The colour identification guide to the moths of the British Isles. Apollo Books.
Thompson, R. & Nelson, B. (2006). The Butterflies and Moths of Northern Ireland. NMNI, Belfast.
Waring, P. & Townsend, M. (2009). 2nd edition. Field Guide to the Moths of Great Britain and Ireland. British Wildlife.

Text written by:
Allen & Mellon