A Review of Lepidoptera in Britain during 1972

A REVIEW OF LEPIDOPTERA IN BRITAIN DĂœRING 1972 BARON DE WORMS VERY

mild weather again prevailed during the first three months of 1972 with comparatively few cold spells. This period culminated in the middle of March with almost a fortnight of remarkably warm weather for the time of year and continuous sunshine which brought out all the hibernating butterflies in force. In particular the Comma (Polygonia c-album L.), Brimstones (Gonepteryx rhamni L.), and Small Tortoiseshells (Aglais urticae L.) were especially numerous in Dorset during the third week of this month.

The Easter week-end feil during the first days of April which also opened with some very congenial conditions. In the Wye Valley on the edge of Monmouth the early spring and very local noctuid the White-marked (Gypsitea leucographa Schiff.) was unusually plentiful as it was also in its other restricted haunts.

By the middle of April Orange-tips (Anthocharis cardamines L.) and Holly Blues (Celastrina argiolus L.) were already on the wing in the south of England, indicating what an early season it was.

During the latter half of April the beating of the blackthorn blossom in various areas of the southern counties produced many larvae which eventually turned into specimens of the Sloe Pug (Chloroclystis chloerata Mabille). This small geometer had only been recognised as a British species in 1971. It was subsequently found not only to be widespread over most of southern and parts of eastern England but that several examples, mostly bred, were discovered in series mixed with its near relative the Green Pug (C. rectangulata L.), some going as far back as the 1940s. Reasonably propitious conditions continued during the first half of May which saw the emergence of many spring butterflies notably the Pearl-bordered Fritillary (Clossiana euphrosyne L.), the Wood White (Leptidea sinapis L.), and the Dingy Skipper (Erynnis tages L.). But towards the end of May one of the most inclement spells set in which was to last during more than half of June, making this month one of the coldest on record for the Century.

This prolonged lapse in the general weather pattern was to have a most adverse effect on the prevalence of lepidoptera for most of the remaining summer and the rest of the year. A general feature was the amazingly small numbers of night-flying insects which were attracted to mercury-vapour lights throughout this bleak period at the height of the season. However, there was at least one bright glimmer in these otherwise lean and sombre few weeks.

This was the discovery of a new habitat for the very elusive small noctuid, the Marsh Moth (Hydrillulla palustris HĂźbn.) which was found to be plentiful in a part of Lincolnshire over a wide area and the males were seen in greater numbers than ever before

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about the middle of June. This species seems to have a habit of appearing on nights when most moths will not fly.

It was not, however, tili almost the middle of July that the elements at last relented and the wärmest conditions since March supervened bringing out many insects which had been lying dormant awaiting the onset of a favourable spell so that the season eventually became one of the latest of recent years. For instance the Marsh Fritillary (Euphydryas aurinia Rott.) which normally is on the wing at the end of May and in early June was only Aying in early July in Cornwall, while the Purple Emperor (Apatura iris L.) only started to appear right at the end of July instead of in the first weeks of that month and was still to be seen at the end of August.

In fact nearly all the butterflies and many of the moths were nearly three weeks behind their normal date of emergence. The arrival of the hot weather about the middle of July coincided with apparently the only wave of migration which came to our shores during 1972. The most notable visitor was the Bedstraw Hawk (Celerio galii Rott.) of which there must have been quite an influx since two of this fine insect were taken in Suffolk and its ränge extended to Devon, but none very far north which seems to indicate a migration from east to west probably from Northern Europe. This surmise is also supported by the record of several Scarce Silver-Ys (Plusia interrogationis L.) in the south of England of a form emanating from Scandinavia and quite different from the normal Scottish or north of England race. But the most surprising record of all was that of two examples of the Scarce Brindle (Apamea lateritia Hufn.) both taken within -the metropolitan area of London, on successive nights in the third week of July. Only one previous example of this large noctuid moth, which is comparatively widespread abroad, had ever been recorded in the British Isles and that was as far back as 1882 in Glamorgan, South Wales. So that it is possible that this species may become a new coloniser with us. Also at about this period there were quite a number of sightings of the Painted Lady (Pyrameis cardui L.) which seems to have been reasonably prevalent, though sporadic, in the south of England. In the Scottish Highlands ova and larvae of the fine moth, the Kentish Glory (Endrotnis vericolor L.) were far more plentiful than for many years as also were those of the northern race of the Oak Eggar (Lasiocampa querciis L.).

During the second half of July a remarkable discovery was made for Eire, that of the occurrence of that beautiful noctuid moth, the Northern Dart (Amathes alpicola Zett.) which was taken on top of one of the mountains in Co. Mayo. Previously it had only been known from over a 2,000 ft. elevation in the

175 eastern Highlands of Scotland and the Lake District where it was first noted shortly after the last War. In Shetland it occurs as well, but at much lower elevations. This fine insect may well exist in other mountainous regions of the British Isles.

REVIEW OF LEPIDOPTERA

In spite of the very late season several butterflies had a very good year, eventually becoming abundant. One of these was the Chalk Hill Blue (Lysandra coridon Poda) which was in remarkable numbers in some of its restricted localities and especialy on the Peninsula of Portland, which also supported a good population of the Silver-studded Blue (Plebeius argus L.). This little insect was still well on the wing into the second half of August. The Marbled White (Melanargia galatea L.) too was unusually plentiful in a few of its haunts during late July. The month of August was for the most part well below its average of summer temperatures, but those of September and October were well above their normal and in fact it proved one of the best autumns for many years, though providing a great lack of migrants.

In particular these were the large Hawks such as the Death's Head (Acherontia atropos L.) and the Convolvulus (Herse convolvuli L.) which for a second year in succession were virtually absent. Butterflies were on the wing well into October which opened with the thermometer nearly into the 70s. The Whites were still well to the fore such as the Small White (Pieris rapae L.) and the Green-veined (P. napi L.) which was Aying into November as also was the Comma (Polygonia c-album L.) which was exceptionally numerous at this period. But the Red Admiral (Pyrameis atalanta L.) while almost absent from the eastern part of England, was quite plentiful in the south-west during the autumn months.

October too was a very good period for moths, some of which were in unusually good numbers. Among these was the handsome Black Rustic (Aporophyla nigra Haworth) and the Feathered Ranunculus (Eumichtis lichenea Hübn.), especialy at Portland.

There was also apparently a minor immigration in the late autumn of a few of the Delicate Wainscot (Leucania vitellina Hübn.), the White-speck Wainscot (L. unipuncta Haworth), and of the very pretty white Pyrale, the Scarce Olive Pearl (Palpita unionalis Hübn.) which had not been seen for some years. The Greater Frosted Orange (Gortyna borelii Mabile) reappeared in its special haunts on the east coast but only right at the end of September and well into October.

Two further rare migrant species of butterfly which appeared in the early autumn were at least one Camberwell Beauty (Nymphalis antiopa L.) recorded from Suffolk in late September and an American Painted Lady (Vanessa virginiensis Drury) taken in South Devon in early October.

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T o s u m up, 1972 can be considered far from a generally prolific year. It was eventually one of the latest this Century and once more there was on the whole a very great lack of the normal migrants.

Baron de Worms, M.A., Ph.D., F.L.S., F.R.E.S., Three Oaks, Shore's Road, Horsell, Woking,

M.B.O.U., Surrey.