Notes and comments on some Suffolk moths in 1990

NOTES AND COMMENTS ON SOME SUFFOLK MOTHS IN 1990 M . R . HALL

The mild winter, without a period of prolonged frost, meant that once again moths were to be found on the wing early in 1990. One of the earliest records was of the orange underwing, Archiearis parthenias Linn., from Icklingham Belt (CK) in March. Although this is a day-flying species, its fast, purposeful flight frequently makes it difficult to spot. At the same time of year many of the overwintering larvae were beginning to show themselves again and, in spite of their usual habit of only coming out to feed at night, could be spotted readily in the light of a torch or Tilley lantern. One of the more attractive of the heathland larvae is that of the deep-brown dart, Aporophyla lutulenta D. & S., which is quite a bright green, has paler yellowish-green sub-dorsal stripes, a thin, but very obvious red line below the spiracles, and a rather broad greenish ochreous lateral stripe which is edged above and below with white. This was found in good numbers on tufted hair-grass (Deschampsia cespitosa Beauv.) on Wortham Ling (MH) in March, and the adult moth, which flies in September and October, was also recorded at Hollesley (RSL).

Later in the year, on the 26th July, the white colon, Sideridis albicolon Hb., was also recorded on Wortham Ling (MH). This is a species more usually associated with Breckland and the coastal sand-hills in East Anglia. This record from a somewhat isolated, predominantly acid, inland heath extends its known haunts within the county.

The scarce tissue, Rheumaptera cervinalis Scop., which has been seen regularly during the last few years at Monks Eleigh (AW), was also noted at Brandon Country Park (BS) in March and April. With the increasing invasion through some of the coniferous plantations in Breckland by the cultivated Oregon-grape (Mahonia aquifolium Nutt.), this species is expanding its range as the larvae adapt to a new foodplant. Unfortunately other species are apparently still declining, so the record of one that is less common in Suffolk than formerly, the blossom underwing, Orthosia miniosa D. & S from Hollesley (RSL) in 1990 was particularly good news. A related species, the powdered quaker, Orthosia gracilis D. & S., which is also an early season visitor to sallow blossom, whilst still widespread through the county, is another moth that is less numerous of late. Both are said to feed on a range of herbaceous plants, with the young larvae of O. miniosa feeding on oak (Quercus spp.) and then being partial to oak galls before descending to the ground to complete their growth. Two other spring moths that are generally widespread and not uncommon, but nevertheless do not figure prominently in Suffolk records, are the sloe carpet, Aleucis distinctata H.-S., which was again seen in small numbers at Monks Eleigh (AW), and the grey birch, Aethalurapunctulata D. & S., which was recorded from Redgrave Fen on the 23rd April (RM). The more restricted mottled grey, Colostygia multistrigaria Haw., which is usually encountered on the Breck heaths, was recorded from Market Weston Fen on the 20th March (MH).

As the year progressed, with many sunny days, a diurnal species, that has

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been seen more frequently in recent years, was recorded from yet another site. This time the small yellow underwing, Panemeria tenebrata Scop., was observed in early May, in good numbers, on a small fen at Hopton (RM) where the larval foodplant, common mouse-ear (Cerastium holosteoides Baumg.), abounds. The larvae feed on the developing seeds in the capsules.

At the same time of year, on the 15th May, a buttoned snout, Hypena rostralis Linn., was recorded at light in Monks Eleigh (AW). This is a much decreased species that, in recent years, is only casually recorded outside Surrey, Middlesex, Kent and Essex and one which overwinters as an adult and can therefore be seen from August to October and again from late April till early July. In May and June the cream-spot tiger, Arctia villica britannica Ob., was again recorded at Hollesley (RSL), and also at Brandon Country Park (BS) and Lakenheath (MB). In 1989 it had been recorded on the Minsmere reserve (RM) together with the rosy wave, Scopula emutaria Hb., and the bordered gothic, Heliophobus reticulata marginosa Haw. The rosy wave is one of the specialities of the coastal marshes in Suffolk, but Skinner (1984) says that H. reticulata marginosa is rarely seen in numbers outside the Breckland of East Anglia. In recent years it seems to have been much reduced in the Breck, so this coastal record is very encouraging.

At the end of May an evening in Groton Wood revealed the poplar lutestring, Tethea or D. & S., and the seraphim, Lobophora halterata Hufn., both of which have larvae that feed predominantly on aspen (Populus tremula L.), and neither of which are particularly common in the county.

Over 70 species were recorded that evening but the hoped for specialist lime feeders were not encountered. If they are present in the wood their non appearance probably reflects the slightly adverse weather conditions of the evening, a feature of much of the year. This was particularly noticeable on trips to fens, when the temperature almost invariably dropped away very quickly after dark, with an adverse effect on both moths and recorders. On the 20th June, at Thelnetham Fen, the small seraphim, Pterapherapteryx sexalata Retz., and the rosy marbled, Elaphria venustula Hb., were recorded. The small seraphim is locally widespread in damp woodland, fenland and marshy places in southern England and East Anglia, with the larvae feeding on sallow (Salix caprea L.) in the autumn, but the rosy marbled is a local species supposedly of open woodland. The natural foodplant of the larvae is unknown in Britain, although they will eat the flowers of bramble (Rubus fruticosus aggregate), broom (Cytisus scoparius Link) and tormentil (Potentilla erecta Rauschel) in captivity, and recent records indicate that this species is both increasing its range and habitat tolerance and becoming more numerous. Later in the year the larvae of the valerian pug, Eupithecia valerianata Hb., were found at Thelnetham (GH). They were noticed feeding on the flower heads of marsh valerian (Valeriana dioica L.), obviously their foodplant at this site, which shows a deviation from common valerian (V. officinalis L.), which is the more usually reported pabulum.

During the year visits were made to Darsham Marshes (AW) with species being recorded both during the day and at light. In May the dingy shell, Euchoeca nebulata Scop., and the silver hook, Eustrotia uncula CI., were flushed up in the day-time. Both are important species of boggy heathland, Trans. Suffolk Nat. Soc. 27 (1991)

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fenland and marshy places, but it was recording the white-mantled wainscot, Archanara neurica Hubn., at light in August that was the high-light of visits to this reserve. Although not uncommon in the reed-beds of the Suffolk coast this species is known from nowhere else in Britain and is accorded RDB 3 status by the Nature Conservancy Council. On the same night Lempke's gold spot, Plusia putnami gracilis Lempke, and the brown-veined wainscot, Archanara dissoluta Treit., also came to light. Both are noteworthy species of the fenlands of East Anglia and regularly recorded from the coastal reedbeds and the river valley fens. Somewhat paradoxically, on the 13th August the saltern ear, Amphipoea fucosapaludis Tutt, which is usually regarded as inhabiting salt-marshes and coastal sandhills, was recorded at Lopham Fen (MH). However, this is not a unique inland record as it was also recorded from Redgrave Fen in 1969. With the saltern ear on the 13th August, the narrow-winged pug, Eupithecia nanata angusta Prout, also appeared in the trap. The presence of this heathland species, with larvae feeding on the flowers of heather (Calluna vulgaris Hull), although almost certainly a wanderer, does emphasise the devastation that has been wrought upon what has been an internationally important wetland site - ironically designated a 'Ramsar' site of outstanding importance in 1991 - by commercial water extraction from the underlying aquifer for the last few decades.

During the evening at Blaxhall Heath on the 28th July several specimens of the plain wave, Idaea straminata Borkh., were recorded (AW). This is a species that has figured much more prominently in reports in the last few years. This may, in part, be due to an increasing awareness of this species by recorders, but it could also indicate an upturn in its status within the county.

There are several species that have seemingly become more widespread and numerous in recent years. The pine beauty, Panolisflammea D. & S., which can be a pest in northern pine forests, has spread throughout the region, and another conifer feeder, Blair's shoulder-knot, Lithophane leautieri hesperica Bours., continues to gain ground since the first Suffolk record at Monks Eleigh in 1980. The shuttle-shaped dart, Agrotis puta Hb., which had virtually disappeared in 1988 and 1989, re-appeared as strongly as ever in 1990. The brick, Agrochola circellaris Hufn., continues to appear as isolated individuals at Monks Eleigh (AW), so there must be some hope that this once common elm-feeding species will eventually regain its former status. A species that is renowned for quite dramatic expansion and contraction in its range, the dotted rustic, Rhyacia simulans Hufn., was hardly seen at all in 1990, after several years of comparatively prolific records.

In the ever changing environment of the 1990's the status of our moth fauna is fluctuating all the time. In order to get some idea of the itensity, and perhaps permanence, of these changes as many records as possible are needed. Do send copies of all your records, whether from regular light trapping or casual observance, to the county recorder, Arthur Watchman, Onchan, Back Lane, Monks Eleigh, Suffolk, IP7 7BA, or to the Suffolk Biological Records Centre, c/o The Museum, High Street, Ipswich, IP1 3QH. At the time of writing there are several of the regular recorders from whom we have not yet received 1990 records - we would be delighted to receive them.

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Acknowledgements I would like to thank those recorders whose records have helped to compile this report: Mick Bentley (MB); Gerry Haggett (GH); Chris Kitchen (CK); Rob Macklin (RM); Ray Mitchell (RM); Robert St. Leger (RSL); Barry Stuart (BS); and in particular Arthur Watchman (AW) for much detailed comment on species and numbers in general.

References Skinner, B. (1984). Colour Identification Guide to the Moths of the British Isles. Middlesex: Viking.

M. R. Hall (MH), Hopefield, Norwich Road, Scole, Diss, IP21 4DY

Trans. Suffolk Nat. Soc. 27 (1991)