Heart Moth  (Dicycla oo)

Classified as Rare in Great Britain (2).

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).

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 Gateway.

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

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).

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

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 Gateway.

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

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.