A Review of Lepidoptera in Britain during 1975

A REVIEW OF LEPIDOPTERA I N BRITAIN D Ü R I N G

1975

b y BARON DE WORMS

As indicated in my review for 1974, the end of that year was one of the milaest winter periods on record so that the Start of 1975 saw an amazingly precocious season. T h e early geometers, such as the Spring Usher (Erannis leucophaearia Schiff.) and the Early M o t h (Theria rupicapraria Schiff.) were in füll swing the first days of January which also saw the emergence of the noctuids, the common Quaker (Orthosia stabilis Schiff.) and the Clouded Drab (O. incerta H u f n . ) several weeks ahead of normal. T h e Vegetation too kept apace with the early appearance of insects.

T h e springlike conditions continued almost throughout February with the record of the Yellow-horned (Achlya flavicornis Linn.) at the middle of that month. As was to be expected, this remarkable start to the year was bound to have a major setback. This came with the Easter holiday at the end of March when there were heavy snowfalls. However, the latter part of April was very congenial with plenty of spring warmth and sunshine which brought out the first Whites in plenty also the Orange-tips by the end of that month. T h i s was followed by a fairly cool start to May. However, during its latter half the Wood White (Leptidea sinapis Linn.) was once more in very good numbers in its Sussex haunts together with both the Small Fritillaries, the Large and the Small Pearl-bordered {Ciossiana euphrosyne Linn.) and (C. selene Linn.). After yet another short cold snap at the end of which brought falls of snow in early June, there was a sudden change for the better with a veritable heat wave to start the second week which was the prelude to the long and one of the hottest summers this Century. Insects, especially the lepidoptera, began to appear in real plenty in most parts of the country, but it was surprising however, that hardly any migrant species of note were recorded at this period. An unexpected visitor to Eire at this time was the small noctuid moth, the Purple Marbled (Eublemma ostrina Hübn.). At the end of June there was a spate of Marbled Whites (.Melanargia galatea Linn.) on the downs and elsewhere. T h e Small Blue (Cupido minimus Fuessly) had also had a prolific first brood apain.

T h e turn of the year saw a continuance of the exceptionally fine weather and also a generally good emergence of butterflies and moths. Both the White Admiral (Limenitis Camilla Linn.) and the Purple Emperor (Apatura iris Linn.) were well in evidence by the second week of Julv with both of these wood-loving insects in reasonable numbers as was also the Silver-washed Fritillary (Argynnis paphia Linn.). After a short break in the warm spell in the middle of July the heat wave returned with füll force at the third week in that month which saw a fine second brood of the

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Wood White (Leptidea sinapis Linn.) again in its Sussex localities.

It was however, the first ten days of August which proved quite phenomenal with tropical temperatures and in the shade the thermometer stood for five days in succession at over 90°F, almost unheard of in this country. Naturally it was a hey-day for the moths at night. Some quite remarkable catches were recorded with more than a hundred species in a single session at mercury vapour light in a locality near the coast in Suffolk where the Buff Footman (Eilema deplana Esp.) was remarkably plentiful.

The second brood of the Oak Hook-tip (Drepana binaria Hufn.) was also unusually abundant at this period in August which saw the capture of a few Bedstraw Hawks (Hyles gallii Rott.), both in Scotland and even on the outskirts of London. These insects may well still be the aftermath of the great incursion of this species in 1973. A good many Painted Ladies (Vanessa cardui Linn.) appeared about this time in many parts of the south of England. The Peacocks (Inachis io Linn.) became reasonably numerous, but the Red Admirals (Pyrameis atalanta Linn.) seemed to patronise the more western areas of the south of England as did the main summer broods of the Small Tortoiseshell (Aglais urticae Linn.). But it was towards the end of August and in early September that the main influx of migrants appeared, and this was chiefly in the extreme south-western regions of Cornwall and also in parts of southern Ireland, which saw a remarkable invasion of the Clouded Yellow (Colias croceus Fourcroy). In a few small areas in both these regions this migrant butterfly was more plentiful than it has been for a great many years. Several were even seen in the Outer Hebrides where there have been very few records over the years. Other migrant species recorded in this part of Cornwall, chiefly on the Lizard Peninsula, included several Striped Hawks (Celerio livornica Esp.) and the Ni moth (Plusia ni HĂźbn.). What might almost be called the 'moth of the year' was without question the Cosmopolitan (Leucania loreyi Dup.) which hitherto has been regarded as of very rare occurrence with an occasional specimen every few years.

From late August tili the middle of September nearly thirtv examples were recorded from the Lizard, the Scillies and the south coast of Eire. From the last source ova were obtained and a series bred out in the late autumn by Dr. A. Myers, possibly for the first time in the British Isles. As this moth's name implies, it is a subtropical species which, as already emphasised, only very occasionally reaches our shores but there is evidence that it may have actually bred naturally with us.

Again at this same period a remarkable discovery was made also in the most south-western region. In the late summer of 1974 two collectors had by chance bred out from wild-found larvae two examples of a noctuid moth which at first was thought to be an unusual form of the common Flounced Rustic (Luperina

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testacea Schiff.). But on a revisit to the same locality in late August, 1975, this moth proved to be quite plentiful as it sat about on grass stems after dark. It was then recognised to be an entirely hitherto unknown race of Guenee's Sandhill Rustic (Luperina nickerlii Freyer) which has as yet not been fully described in the literature.

Düring the latter part of the summer the Gatekeeper (Maniola tithonus Linn.) had been exceptionally plentiful, while its near relative the Meadow Brown (Maniola jurtina Linn.) had had one of its leanest years for a long time. Once more the Chalkhill Blue (Lysandra coridon Poda) was abounding in some of its restricted localities. Both larvae of the Bedstraw Hawk and the Death's Head (Acherontia atropos Linn.) were found at this period in September, since there had been reports of a few of this latter grand moth earlier in the summer. Very few Convolvulus Hawks (Herse convolvuli Linn.) were noted, though there was at least one in Suffolk. But the prizes were an Oleander Hawk (Daphnis nerii Linn.) taken in Hampshire in late August with another on Canvey Island at about the same date.

The autumn proved to be on the whole very mild and congenial, with quite a good showing of some of the late species of moths.

Though there was a paucity of Red Admirals, Commas and Small Tortoiseshells in the eastern regions, these were reasonably numerous in the south-west where there was a big emergence of the White-speck Wainscot (Leucania unipuncta Haworth) in early October with a few of the Delicate (Leucania vitellina Hübn.).

Blair's Pinion (Lithophane leautieri Boisd.) was once more recorded in the London area. This insect is steadily increasing its ränge among macrocarpus, its larval pabulum, which is also that of the Black-streaked Pug (Eupithecia phoeniceata Rambur) which is also subject to a similar phenomenon in south-eastern England.

The record of a very rare moth has recently been disclosed.

In 1972 Mr. J. Reid bred out a specimen of the Scarce Wormwood Shark (Cucullia artemisiae Hufn.) from a larva found feeding the previous year on Artemisia vulgaris at Nazeing in Essex. There are very few authentic British specimens of this fine noctuid.

To summarise, the very remarkable long and fine summer of 1975 was the key to a big emergence of the lepidoptera and made it in many ways a most memorable year, though its relative dryness caused some species to be below average in their numbers.

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