Notes and comments on some Suffolk moths in 1993

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NOTES AND COMMENTS ON SOME SUFFOLK MOTHS IN 1993 M. R. HALL Following the publication of the 1992 moth notes last year, I was very pleased to hear that in July 1992 a specimen of the double line, Mythimna turca Linn., had been recorded at Aldringham (JF). This is a woodland moth that is now found most commonly in suitable areas of Cornwall, Devonshire and Somerset, south-west and central Wales and Cheshire and is thought ot have vanished from many of its old haunts in the eastern part of southern England. Morley (1937) makes no reference to this species and as I can find no other mention of it from Suffolk I believe this to be a new county record.

On the same night, at the same site, the Pyralid Apomyelois bistriatella HĂźlst, was also recorded (JF). This species was mentioned in last year's notes, where it was claimed as a new county record. Since then Mr. Alasdair Aston has written to say that it was first recorded in Suffolk in 1935 and subsequently on several other occasions [see separate paper], I am most grateful to Mr. Aston for bringing these records to my notice and apologise to him for the mistaken claim.

The revival of the cream-spot tiger, Arctia villica britannica Ob., continues both at Hollesley (RSL), where it was considerably more abundant that the usually more common garden tiger, Arctia caja Linn., and in the King's Forest (RE). It was at Hollesley that the grass wave, Perconia strigillaria Hb., made its second recent re-appearance in the county [the first being at Minsmere last year] when three were recorded (RSL). Similarly the black rustic, Aporophyla nigra Haw., which made its first appearance at Hollesley in 1992, was recorded at Felixstowe in 1993 (NO). This heathland species has only rarely been seen in Suffolk and is more usually found further to the west.

Several of the Breckland specialities were again recorded from a ränge of sites with the tawny wave, Scopula rubiginata Hufn., and the grey carpet, Lilhostege griseata D. & S., in evidence in the King's Forest (RE). the tawny wave also being recorded at Lakenheath (BS) and the marbled clover, Heliothis viriplaca Hufn. again Coming to light near the coast. In 1993 it appeared at Trimley (TW) and on Orford Ness (MM). The pauper pug, Eupithedcia egenaria H-S., was recorded as both the larva and the adult insect from lime trees within the King's Forest (RE) making this the first site "well into Suffolk" for this species. Previously it has only been known in the county from the Santon Downham area where it is contiguous with the Norfolk Breckland colonies.

Two coastal species, associated with salt marshes, that are well established within the county but have not been noted very much in recent years are the star-wort, Cucullia asteris D. & S., and the ground lackey, Malacosoma castrensis Linn. The former, which is to be found from the Thames estuary to the Holderness peninsula [as well as along parts of the southern and western coasts of Britain], was recorded at Felixstowe (NO) and Hollesley (RSL). The ground lackey also came to light at Hollesley (RSL) and Felixstowe (NO) and the larvae were found in some abundance at Aldeburgh (MH). These larvae, which varied noticeably in size, were all found on Sea Arrowgrass, Triglochin maritimum L., which is not one of the foodplants usually listed.

Trans. Suffolk Nat. Soc. 30 (1994)

NOTES ON SOME SUFFOLK MOTHS, 1993

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The highlight of the year, from the records so far received, was a somewhat worn specimen of the satin lutestring, Tetheella fluctuosa Hb., recorded at Hollesley (RSL). This species is best known on the British mainland from south-east England, chiefly Kent, Sussex and Surrey; also in the Forest of Dean, Gloucestershire and the Wye Valley, parts of the West Midlands and Wales, Cumbria, Inverness-shire and Argyll. Its distribution is unaccountably patchy and Morley suggests that nearly all Suffolk records known to him were doubtful, and adds that it is "Pretty surely extinct with us now . . .". It seems probable that this is only the second record for this species from Suffolk [the first being from Stowmarket as recorded by Stainton (1857)] and almost certainly the first this Century. The satin lutestring is an inhabitant of mature woodland with birch, which is the preferred larval foodplant. It is not usually regarded as a migrant species but it seems likely that this specimen arrived as a wind borne traveller from one of its Kentish strongholds.

Records of regulär migrant species were particularly sparse with the only convolvulus hawk-moth, Agrius convolvuli Linn., being recorded at Felixstowe (NO). The Landguard Bird Observatory moth trap also caught a specimen of the gern, Orthonoma obstipata Faba., on 2Ist September. Abroad, this species has an immense ränge, occurring throughout Europe, Asia, African and North and South America. The only other migrant reported at the time of writing these notes is the delicate, Mythimna vitellina Hb. from Hollesley (RSL).

This paucity of migrant reports reflects the overall lack of sightings of very many of our resident species. All recorders have commented on a "poor year" and in most cases this has been indicated more by low numbers of moths rather than much in the way of particular species not being seen. Inevitably. even when conditions generally have been so poor for actually seeing moths, there are species that have been particularly abundant. One of these is the Vine's rustic, Hoplodrina ambigua D. & S., which has been increasingly in evidence over the last few years, as has the treble brown spot, ldaea trigeminata Haw..

(REd, MH, NO, AW). The common wainscot, Mythimna pallens Linn., also seemed particularly common in 1993. The varied Coronet, Hadena compta D. & S., was noted from several sites; although well established throughout East Anglia, at least since the 1970s, it fluctuates in abundance. The almost exclusive preference of sweet William as a larval foodplant and the fluctuations in popularity of this garden plant almost certainly explain its local population changes. Another record of the day-flying hörnet moth, Sesia apiformis Cl„ has been received, this time from Monks Eleigh (AW). Arthur Watchman discovered a newly emerged female on grass at the base of a White Poplar at 8.30 a.m., and at that time her wings were not fully expanded. By 11.00 a.m. it had climbed some two feet up the trunk of the tree and was in cop.

One of the more interesting records is of the rufous minor, Oligia versicolor Borkh., from Framlingham (PH & RS). This is a species where positive identification can only be given after a microscopic examination of the genitalia, which is how the Framlingham specimen was determined, and even so there are some authorities that question the validity of the rufous minor as a separate species as it cannot be readily verified by a captive breeding programme.

Another species where there has been confusion with a closely related species of similar appearance is the lesser treble-bar, Aploceras efformata Guen., but

Trans. Suffolk Nal. Soc. 30 (1994)

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Suffolk Natural History, Vol. 30

this can be distinguished from the treble bar, Aplocera plagiata Linn., on visible markings. A singleton was recorded at Hollesley (RSL) but it is uncertain just how widespread, or abundant, this species is in Suffolk because of the confusion [Morley makes no comment as to distribution and simply says "Doubtless mixed with the last species (the treble bar)"].

More easily separated from a similar relative is the peacock moth, Semiothisa notata Linn., although this woodland moth is by no means common. It was recorded at Thornham (MH) where the oak lutestring, Cymatophorima diluta hartwiegi Reisser, was also noted as still comparatively abundant in this area of secondary woodland, although, as yet, not recorded anywhere eise in Suffolk in modern times. The vagaries in distribution of moth species showing an apparently erratic occurrence has continually intrigued field lepidopterists. The plumed prominent, Ptilophora plumigera D. & S., with larvae feeding on Field Maple, is far less widely distributed in Suffolk than its preferred pabulum. It was first discovered in Suffolk at Needham Market in 1937 by Mr. E. W. Platten and by 1960 had become the object of pilgrimages to Barking Woods, but it was also to be found in several other woods on the boulder-clay (Aston, 1961).

Today, whilst still found in these habitats, it has also been recorded from scattered sites around Needham Market through towards Sudbury, and not always in woodlands. It seems likely that the plumed prominent Caterpillar requires Field Maple growing on a chalky soil to produce acceptable food. It regularly occurs in some numbers at a garden light in Monks Eleigh (AW) and in 1993 two females were noted.

The somewhat adverse conditions for moth recording endured in 1993 have been reflected in fewer than usual reports being received. If you have 1993 records do please still send them 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, together, of course, with any later records.

Acknowledgements 1 thank those recorders whose records have helped to compile this report: Russell Edwards (REd), Rafe Eley (RE), John Fenn (JF), Peter Hall & Robert Shepperson (PH & RS), Mike Marsh (MM), Nigel Odin (NO), Robert St. Leger (RSL), Bernard Skinner (BS), Tony Worledge (TW), and in particular to Arthur Watchman (AW) whose detailed comment on species and general numbers is so valuable.

References Aston, A. (1961). The Lepidoptera of Suffolk. Trans. Suffolk Nat. Soc. 11: 482.

Morley, C. (1937). Final Catalogue of the Lepidoptera of Suffolk. Ipswich: Suffolk Naturaiists' Society.

Stainton, H. T. (1857). A Manual of British Butterflies and Moths. 1: 175.

London: John van Voorst.

M. R. Hall (MH) Hopefield, Norwich Road, Scole, Diss IP21 4DY. Trans. Suffolk Nat. Soc. 30 (1994)