Heart Moth (Dicycla oo)

Heart Moth
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Heart Moth fact file

Heart Moth description

GenusDicycla (1)

The Heart Moth is pale in colour with light brown patterning and off-white hind-wings. It takes its common name from the single heart-shaped mark on each forewing (3). The caterpillar has a black back with three white lines, and has a brown underside (4).

Wingspan: 32- 38 mm (1)

Heart Moth biology

This moth is single-brooded, and adults fly between late June and July. The caterpillars are active at night between April and early June, and spend the day concealed in a tent of leaves held together with silk (1). The overwintering stage is the egg (1).


Heart Moth range

The only sizable populations at present occur in Surrey, but this moth also persists in the Windsor Forest area in Berkshire, Northamptonshire, and there has been a recent record from the north-west of Kent, the first record here for around 80 years (5). It is known to have become locally extinct in Essex, Buckinghamshire, Middlesex, Hertfordshire and Hampshire. Despite being known from most European countries, it is extinct, rare or local in many areas (2).

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

Heart Moth habitat

Inhabits parkland and open woodland. The caterpillars feed preferentially on mature pedunculate oak (Quercus robur) (2).


Heart Moth status

Classified as Rare in Great Britain (2).


Heart Moth threats

The widespread felling of mature oaks preferred by the caterpillars is thought to have been of major significance in the decline (2).


Heart Moth conservation

A Species Action Plan has been produced for the Heart Moth under the UK BAP (Biodiversity Action Plan). This plan aims to maintain all known populations of this species, with enhancement of the populations by 2010 (2). These aims may be achieved through appropriate habitat management and creation, agri-environment schemes, and by linking fragmented habitat patches together (2). In addition, research into the detailed habitat requirements of this species in order to guide suitable habitat management has been underway for a couple of years, directed by Butterfly Conservation (5).

View information on this species at the UNEP World Conservation Monitoring Centre.
There may be further information about this species available via the National Biodiversity Network Atlas.
The UK Biodiversity Action Plan for this species is available at UK BAP.

Find out more

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



Information authenticated by Graham Collins.



Agri-environment schemes
These schemes allow the government to compensate farmers for using methods that benefit the environment. The two main initiatives in the UK are the Countryside Stewardship Scheme and Environmentally Sensitive Areas. Since October 2000 these have formed part of the England Rural Development Programme (EDRP), administered by DEFRA, the Department of Environment Food and Rural Affairs. See http://www.defra.gov.uk/erdp/erdphome.htm for more on these initiatives.
(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. UK BAP Species Action Plan (December 2001): http://www.ukbap.org.uk
  3. Pers. observation from images.
  4. Porter, J. (1997) The colour identification guide to caterpillars of the British Isles. Viking, London.
  5. Collins, G. A. (2002) Pers. comm.

Image credit

Heart Moth  
Heart Moth

© David Green / British Butterfly Conservation Society Ltd

Butterfly Conservation
Manor Yard
East Lulworth
BH20 5QP
United Kingdom
Tel: +44 (0) 1929 400 209


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