1661       Archiearis parthenias (Linnaeus, 1761)     ORANGE UNDERWING   

A widespread day-flying species in Britain, the larva feeding on birch (Betula spp.) and rowan (Sorbus aucuparia).  In Dorset, the moth is recorded sparingly from the eastern half of the county.  Singletons may be seen flying from mid-March on sunny afternoons in woods and on heaths that support birch. “Adult moths may visit sallow blossom and drink at puddles, but then ascend to the birch canopy as the day advances.  They have been found on dull mornings by kicking birch trees hard and watching for the insect fall down” (per W Parkinson Curtis ms.).  The Orange Underwing was rated as locally common prior to the coniferisation of much of the Dorset heathland and reduction in birch habitat.  At the present time colonies are small and fragmented, and nowhere can it be considered common.  Small colonies have been noted in deciduous woodland containing mature birch on clay soils, notably in Boys Wood, and in mixed woodland at Stubhampton on chalky soil.  The lack of records from west Dorset, where birch trees occur in smaller numbers, suggests that the Orange Underwing may be restricted to the eastern half of the county.

1662       Archiearis notha (Hübner, 1803)     LIGHT ORANGE UNDERWING     Notable/Nb

A local day-flying species in southern England, the larva feeding on aspen (Populus tremula).  The moth is very similar in colour, markings and behaviour to the Orange Underwing₁₆₆₁, although the peak of the flight period tends to be roughly ten days later for Light Orange Underwing.  In Dorset, aspen is a scarce tree but the moth is resident within aspen communities at four widely separated sites.  The first, Hurn, in the south-east of the county, is situated on sandy soil next to the Moors River, and hosts a large grove of aspen trees.  The second, Boys Wood, is oak/birch woodland on clay soil in north-east Dorset where several large groves of mature aspen are located; the Orange Underwing₁₆₆₁ is also present in this wood. The third, Fifehead Wood in north Dorset, is damp woodland on clay soil close to the Stour River, and aspen is one of the more frequent trees in the wood.  The third colony, at Deadmoor Common, is situated within old deciduous woodland in the Blackmore Vale; here, aspen is restricted to a handful of mature stands.  Colonies tend to be larger and more concentrated than those of the Orange Underwing₁₆₆₁ and further sites may still be discovered.  Any fieldwork undertaken to locate colonies should target viable communities of aspens, and then closely monitor the tops of the trees on sunny days from the start of April between midday and mid-afternoon, in an effort to detect the moth flying in the lee of the canopy, though the higher the canopy, the greater the chance of cricking one’s neck!  Potential sites to research are few and far between, and include Three Acre Wood and Castle Hill Wood; however, birch, the host plant of the Orange Underwing₁₆₆₁, is also frequent at these sites.  Conservation measures at existing sites should focus on the retention of existing stocks of aspen.

1663       Alsophila aescularia [Denis & Schiffermüller 1775]     MARCH

A common species in England and Wales, less common in Scotland, the larva feeding on many deciduous tree and shrub species, including oak (Quercus spp.), birch (Betula spp.), hawthorn (Crataegus spp.) and blackthorn (Prunus spinosa). The female is wingless.  In Dorset, the moth is one of the first species to emerge in the year. It is common in deciduous woods and amongst scrub, but absent from open coastal areas, for example, Portland.  Singletons are occasionally noted elsewhere.

1665       Pseudoterpna pruinata (Hufnagel, 1767)     GRASS EMERALD

A widespread and common species in Britain, although less common in northern Scotland, the larva feeding on gorse (Ulex spp.), petty whin (Genista anglica), dyer’s greenweed (Genista tinctoria) and broom (Cytisus spp.).   In Dorset, the moth is common on heaths and downs where gorse abounds, and in unimproved grasslandhabitat where dyer’s greenweed flourishes at Rooksmoor in the Blackmore Vale.  Larvae have also been found on broom at Parley Common and along the Wimborne by-pass. 

1666       Geometra papilionaria (Linnaeus, 1758)     LARGE EMERALD 

A generally distributed species in Britain, the larva feeding on birch (Betula spp.), and less frequently on beech (Fagus sylvatica), hazel (Corylus spp.) and alder (Alnus spp).  This is the largest of the Emeralds, with a wingspan of up to 65mm.  In Dorset, the moth is most frequent where birch grows in deciduous woods on sandy and clay soils and on heaths.  Favoured sites include Arne Wood, Hurn, Whitesheet, Boys Wood and Castle Wood.  Elsewhere it is scarce.

1667       Comibaena bajularia [Denis & Schiffermüller 1775]     BLOTCHED EMERALD

A locally common species limited to southern and eastern England and Wales, the larva feeds on oak (Quercus spp.).  In Dorset, the moth is local and confined to woodland containing oak where it can occasionally be common: Boys Wood, fifty-eight at MV light on 15 June 2003 (C Manley, P Davey). It is seldomencountered far from deciduous woodland.  The following specimen was trapped at the end of a famously warm summer and is likely to have been a second brood individual: Holnest, at MV on 14 September 1959 (H Moore).

1669       Hemithea aestivaria (Hübner, 1799)     COMMON EMERALD

A species found in England and Wales, the larva feeding on many deciduous tree and shrub species, including oak (Quercus spp.), birch (Betula spp.), hawthorn (Crataegus spp.) and blackthorn (Prunus spinosa).  In Dorset, the moth is ubiquitous and often common, particularly so in blackthorn communities close to thecoast. In unusually warm summers, second brood individuals may result as evidenced by the following records: Furzey Island, at MV light on 18 September 2003 (Dr P Sterling), Matchams, at MV light on 14 September 1982, 25 September 1986 and 27 September 1986 (G Le Pard).

1670       Chlorissa viridata (Linnaeus, 1758)     SMALL GRASS EMERALD     Notable/Na

A very local species in southern England and the Lake District, the larva feeding on heather (Erica spp.), birch (Betula spp.) and creeping willow (Salix repens).  In Dorset, the species is very local being confined to wet heaths and mire on sandy soils across the Poole Basin where it occurs at low density.  The moth readily takes to the wing when disturbed during the day.  Many of the localities where colonies occur lie within SSSIs.  Continued monitoring is recommended although threats posed to the species in Dorset are considered to be small at the present time.  

1672       Thalera fimbrialis (Scopoli, 1763)     SUSSEX EMERALD     RDB1

Resident at Dungeness in Kent, and, prior to 1950, probably resident on the Crumbles near Eastbourne in Sussex, otherwise a very rare immigrant, the larva has been found feeding on wild carrot (Daucus carota) and ragwort (Senecio spp.) in south-east England; abroad it is often found on yarrow (Achillea spp.). The species is resident across much of Europe between 35°N and 55°N, colonising dry open habitats on stony, rocky or sandy soils.  In Dorset, two individuals have been recorded; both were found in coastal localities and both are suspected immigrants: Scar Bank, at light on 11 August 1936 (A Russell), Bournemouth, at light 29 July 1946 (Mansfield, The Entomologist, 79:212).

1673       Hemistola chrysoprasaria (Esper, 1794)     SMALL EMERALD

A locally common species in southern Britain, very local in northern England, the larva feeding on traveller’s joy (Clematis vitalba), and abroad also on Ranunculaceae species.  In Dorset, the moth is found wherever traveller’s joy grows in woods, plantations and hedges, mostly on soils with high calcium content.

1674       Jodis lactearia (Linnaeus, 1758)     LITTLE EMERALD

A species occurring in England and Wales, the larva feeding on birch (Betula spp.), hazel (Corylus avellana), hawthorn (Crataegus spp.), oak (Quercus spp.), sweet chestnut (Castanea sativa) and bilberry (Vaccinium myrtillus).  In Dorset, the moth is at low density in deciduous birch-oak woods on chalky soils such as Stubhampton Bottom and Chetterwood, and on clay soils such as Piddles Wood, Yellowham Wood and Boys Wood.  Adults may be flushed out from hazel understory in these localities. The moth also occurs in deciduous birch and sweet chestnut woodland on sandy soils such as Arne Wood and Whitesheet.  Although there is partial emergence in May, the main flight period for the species is June and July which is later than the national norm of May and June; a partial bivoltine cycle is suspected in Dorset.