Norfolk Survey c/o Natural History Dept., Castle Museum, Norwich, NRi 3 JU.

Newsletter No. 26. April 1990

Since our survey was launched in 1985 we have produced a number of newsletters, information sheets and so on. For ease of reference we have decided to start numbering these, including back issues of the previously published ones. The complete list to date is as follows:-

Number 1 December 1985 Introductury letter / instructions for record cards. 2 June 1986 Letter to recorders and list of species requiring information. 3 July 1986 Information letter to local natural history scieties etc. 4 September 1986 Guidance notes for genitalia preparations 5 September 1986 Notes on identification of some autumnal species 6 October 1986 Autumn newsletter 7 November 1986 Letter to National Biological Records Centre recorders 8 February 1987 Reminder letter for workshops 9 May 1987 Notes on identification of some critical species 10 May 1987 Letter including list of events 11 August 1987 Letter 12 August 1987 Newsletter including review of survey so far. 13 October 1987 Letter following collectors workshop 14 January 1988 Reminder letter for workshops 15 April 1988 Spring newsletter including species list etc.. 16 May 1988 Notes on identification of Pugs 17 May 1988 Updated introductory letter 18 September 1988 Reminder letter for review meeting 19 October 1988 Autumn newsletter including field meeting reports 20 March 1989 Reminder letter for workshops 21 April 1989 Spring newsletter including flight times, migrants etc.. 22 May 1989 Notes on identification of Wainscots 23 September 1989 Reminder letter for review meeting 24 November 1989 Autumn newsletter including field meeting reports 25 March 1989 Reminder letter for workshops

Spare copies of some of these are still available on request.

As we are all aware, the weather conditions have a considerable effect on and consequently on our recording of them. Dr. Clive Sheppard has written a very interesting article for us based on his experiences of attempting to predict "good" moth nights by examining the weather data.

Each year we are very grateful to receive records sent in to us by lepidopterists who live elsewhere but visit Norfolk on occasions, This serves to remind us all that when we visit other parts of the country there will be local groups, County Trusts, etc., who will be equally pleased with any records that we can pass on. By way of an example, Roland Rogers tells us of how he discovered a rare oecophorid while on holiday in Cornwall last year. In fact microlepidoptera are somewhat to the fore in this issue with an introduction to pyralids in Norfolk and a note of last years Yponomeutid invasion. If however you are getting fed-up with moths, then Gerry Haggett offers advice on collecting and rearing larvae. Of course you can as always gain first-hand experience by joining us at any of our field meetings or the workshop sessions at the Castle Museum. All are free of charge and our complete programme of events for the summer is as follows:-

Tuesday 8th. May Castle Museum 7.30p.m. We continue our series of identification workshops with a look at Footmen and Nolids. Thursday 31st. May Upton Fen. Meet 8.00p.m. at reserve entrance TG 379137 Saturday 23rd. June Surlingham. Meet 8.00p.m. at Coldham Hall TG 324071. This event is organised in conjunction with the R.S.P.B. and also forms part of the Broads Authority's "Fun in the Broads" programme. Tuesday 26th. June. Weeting Heath. Meet 8.30p.m. at the N.N.T. car park at TL 756881. Saturday 21st. July Roydon Common. Meet at 3.00p.m. to search for caterpillars and dayfliers, or 8.30p.m. for light trapping. Please note that we are visiting a different part of the Common this year. Park alongside the track at TF 687218. Saturday 28th. July Beeston Common. Meet 8.00p.m. in the lay-by at TG 165426. Saturday 18th. August Holt Country Park. Meet 8.00p.m. in the carpark TG 082376. Wednesday 12th. September. Buxton Heath. Meet 7.00p.m. on the track just off the road at TG 171213. Wednesday 19th. September. Wheatfen. Meet 7.00p.m. at TG 324056. Organised in conjunction with the Friends of the Ted Ellis Trust. Tuesday 20th. November. Castle Museum, 7.30p.m. A meeting to review the work of the survey during this year.

Thetford Naturalists Society will again be pleased to see anyone at their informal moth evenings. These will be held on Thursdays 31st. May and 30th. August at 4 Mackenzie Road, Thetford (IL 853831) and 28th. June and 26th. July at 5 Melville Road, Croxton (IL 874867). Further details from Nick Gibbons, Tele. Thetford (0842) 7523+55.

We have been informed that the British Museum (Natural History) is currently selling copies of the two-volume monograph on the British Tortricidae (published by the Ray Society) at approximately half their original price. The cost is £30 for the two volumes or £10 for Volume 1 and £20 for Volume 2. These are excellent and comprehensive books, beautifully illustrated and well worth the money. For further details contact Tony Irwin at the Castle Museum, or the British Museum bookshop direct.

Finally, a reminder as usual to send your records in, with many thanks to all of you who already have. We hope that this season will provide us with yet more information on the moths of Norfolk. Good hunting!

Ken Saul METEOROLOGY AND MOTHS

One of the most endearing features of moths is their sheer cussedness. Try to demonstrate the wonders of the night to an expectant crowd and you can be almost certain to have a dreadful flop on your hands! Murphys' law applies - whenever you think it's a great night for trapping in that distant fen,' the moths think otherwise. It was about fifteen years ago, when casting around for an A-level biology project, that I first looked into the effects that various different weather conditions could have upon the numbers of moths caught at light traps. More recently I have been trying to find the meteorological measurements most useful for predicting the size of moth trap catches. Although interesting species may obviously turn up at any time, it would. be helpful to have some guide for picking a 'good' night to go on that long trip! Large samples also provide a statistically more valid picture of the species present at a site. The main consideration for the factors was that they should be easily measurable with minimal requirements for equipment. Few people are going to have access to recording anemometers for example, but most could stretch to a thermometer and a simple aneroid barometer. In extremis even the regional weather forecasts will give approximate values of many weather conditions (especially the early evening local broadcasts). The catch of positively phototropic moths at a light trap is proportional both to the available population and to their activity. The population to be sampled for any individual night can be considered to remain roughly constant. It is therefore activity which is going to largely dictate the catch and it is this which the meteorological factors are likely to affect. These factors are also interrelated. To try to assess their relative contribution I have had to apply some statistical analysis to them. Multiple regression analysis (MRA) is a method which allows the comparison of a series of samples whose variation is considered to be due to several factors. It then allows one to calculate the regression of a predicted variable upon a weighted combination of predictor variables. MRA will always maximize the correlation for the particular set of data from which it was derived. METHOD ******

A 125w Robinson pattern MV trap was run for 33 consecutive nights in July and August from 2200 BST to 0400 BST and records of the following weather conditions were kept:

* Maximum shade temperature (centigrade) of the preceding day (Mx).

* Minimum temperature (centigrade) of the trapping night (Mn)

* Atmospheric pressure in mmHg (Pr).

* Cloud cover - estimated at start of trapping in tenths (C).

* Rainfall (inches) - standard rain gauge (Rn). * Relative humidity % - Wet & dry bulb hygrometer (RH). * Windspeed - estimated on Beaufort scale at start of trapping (W). N.B. To approximately convert millibars to inches of mercury and In.Hg to mmHg: In.Hg = (0.02956 x millibars)- 0.0327 mmHg = In.Hg x 25.4

ANALYSIS ******** The simple correlation coefficients (r) which related the catch numbers to the different factors were as follows (p = measure of significance): r p Pressure 0.4735 0.01 RH 0.1697 NS Wind -0.1525 NS Cloud -0.0840 NS Min Temp 0.3886 0.05 Max Temp 0.5431 0.001 Rainfall -0.3107 NS (NS = Not significant) Such correlation coefficients relate each factor individually to the numbers of moths caught, ignoring any effects that the other weather conditions were having. Perfect correlation would be shown by an 'r' value of 1 (or -1), no correlation by a value of zero. The minimum temperature is not useful for prediction as it can only be read after trapping has finished. It looked as if I should concentrate upon the other two factors. I was interested to see if I could find any combinations of factors which might be of greater predictive value than maximum temperature alone. A multiple regression analysis including all the factors showed that there was a very significant relationship (p=0.0036) between weather conditions and catch size. Significance test for prediction of Nos: Mult-R R-Squared SEest F(7,25) prob (F) 0.7343 0.5392 97.6746 4.1794 0.0036 Next the contribution of each factor to the correlation was examined to decide upon the most promising combinations of conditions to examine subsequently. Significance tests for predictors of Numbers: Predictor b se t(25) Pr 6.6875 4.5775 1.4610 0.1565 RH 2.8011 2.5360 1.1045 0.2799 W -11.7314 20.2004 0.5807 0.5666 C 7.0211 5.3803 1.3050 0.2038 Mn -7.5272 10.0855 0.7463 0.4624 Mx 23.3094 6.4512 3.6132 0.0013 Rn -457.8060 482.4345 0.9489 0.3517 Looking at the significance column ('p') the effects of maximum temperature were again highly significant but those of pressure in this case appeared not to be. However some factors may seem to have a low (or even zero) correlation with the predicted factor but may nevertheless contribute by supressing or enhancing the effects of another variable It is not therefore always safe to assume that apparently significant factors are the only ones to consider. By testing different combinations of factors I found that the combination which gave the maximum predictive value for the minimum effort was to use the pressure and maximum temperature combination as suggested initially by the simple correlation coefficients. This resulted in a slight decrease in the multiple correlation coefficient from 0.7343 to 0.6665. Significance test for prediction of Nos: Mult-R R-Squared SEest F(2,30) prob (F) 0.6665 0.4443 97.9195 11.9924 0.0001 (Highly significant) Significance test(s) for predictor(s) of Nos: Predictor b se t(30) Pr 8.8249 3.1084 2.8390 0.0080 Mx 16.0081 4.6444 3.4467 0.0017 Regression Equation for Nos: Nos = (8.8249 x Pr) + (16.00 x Mx) - 6911.89 (Where pressure is measured in mmHg and temp in degrees centigrade) This was then applied retrospectively to the trapping period and resulted in the predicted curve shown in the graph against the actual numbers caught. At this site during July & August any predicted value over about 250 is likely to indicate a 'good' night. CONCLUSION ********** I hope to test this relationship further over the next year and trust that some amongst you might wish to try out the above equation as a way of trying to predict trap catches. Strictly it would apply only to the one site at the same time of year as it was calculated. If you would like me to analyse data from your own sites then I would be happy to do so, it would be simplest if the data came from a limited period when the species diversity remained fairly constant. It might also be interesting to pool all the data from a given month (say July) and analyse them together. Happy Hunting! Dr Clive Sheppard Sustead House Stow Road Magdalen Kings Lynn Norfolk PE34 3BD

Moth Trap Catches 600.00

500.00

900.00

0 Z IMAM, 0 () 200.00

100.02

0.00 Time Caaws) 0 Aotual + Predloted MOTHS ON HOLIDAY

I took my MV lamp to Cornwall when I went there on holiday last year. I stayed with friends in St. Ives, in the town, and set up the light in their garden.

On the night of the llth./12th. July there came to the light a small brown micro with a bright orange fringe to the wings. Not being able to find it in any of my books, I sent photographs to the County Museum in Truro, who sent them to the local lepidopterist. He could not name it either so I sent the photographs to the Natural History Museum. Dr. K. Sattler identified it as Parocystola acroxantha (Meyrick) (Oecophoridae).

On checking, I found that this was only the second record of this species for Cornwall, the first having been at Camborne on 2/3.6.85. The moth, which originates from Australia and New Zealand, is established in South Devon and there has been one record from Somerset. The larva is said to feed on Eucalyptus.

I recorded several other species last year. In addition to the imagines, nearly every ragwort plant I saw, which was plenty, was covered with Cinnabar larvae. There were also a lot of Six-spot Burnet larvae and pupae on the grassy dunes near Hayle. I even saw a Six-spot Burnet larvae amongst the Cinnabar larvae on a ragwort plant!

Roland Rogers.

CATERPILLARS FOR ALL

Although to some of us the caterpillar stage can be the most interesting of the four phases of a moth, others will say that is all very well when you know the 900 or so macros and maybe some of the micros, but the majority of us don't and so remain handicapped. And all the while there are no popular, modern books portraying larvae, harsh truth dictates the only path to be that of personally rearing wild-found or captive ones from wild female moths. This should not deter the tyro from happy hours of hunting and observing, but it does entail rearing unknown individuals separately with accurate details of location, food, date, and simple but readily recallable description of larvae in their last skin if not of earlier ones too.

Indiscriminate collecting of larvae by beating and sweeping, while numerically more rewarding, also results in their being collected together from a range of plants. Beating can be organised so as to work only one type of bush or tree at a time, and we looked at a simple tray at one of our past meetings which is suitable for holding freely below foliage rather than to be pushed into it. In practice it is surprising how rarely foliage is nicely displayed for convenient beating, more commonly it is a jumble of unyielding branches, as any thorn, gorse or even elder bush will testify. For that reason as stiff a tray as can be constructed - or held - will give greater flexibility of use. Birch, oak and sallow yield the largest number but few trees or shrubs do not harbour some larvae. Remember the aim is to jar larvae from their resting positions so a sudden tap is not only less energetic but less damaging to the environment.

Sweeping requires a net bag of tough, durable material, heavy enough to withstand the harsh friction of herbage and stems,but pliable enough to retain its shape. Heavy denim, serge or sailcloth are recommended but all require making up with the strongest of needles that alas will not adapt to the average domestic sewing machine. Sweep nets offered by the suppliers of entomological apparatus are frankly exasperating and of such excruciatingly poor design that they last no more than a few outings despite their outrageous high cost and guarantee of raising blisters. The old-fashioned net was held on to its brass support ring by metal curtain rings and built to last as my Victorian example bears witness. But sweeping with the right net is a delight, a wonderful sampling tool for all habitats but especially coming into its own in the breck heaths and wetlands. As with the beating tray each series of sweeps or beats engenders excitement of what larvae the next inspection will reveal, along with a multitude of other , seeds and plant debris.

Of course larvae can be found simply by examination of foliage and flowers and for the larger ones that grip tightly there is no better method; hawks, eggars, prominents and some larger geometers will be so found and practice will be perfected in knowing the most likely situations along twigs, in bark fissures, beneath foliage or near to part-eaten leaves. For the bulk of noctuids and loopers, however, searching at night will be more productive simply because they hide by day in low vegetation. The brighter the lamp the better so long as it is dependable in mixed weather without being too heavy;most common use is the Tilley lantern, formerly Primus or Bialladin which burn vapourised paraffin and attract moths as well! but prolonged use can cause numbing of the arm. Searching at night is a world apart from most other forms of collecting, the serenity yet excitement of viewingsecrets of the dark revealed in the nostalgic soft roar of the lamp with occasional whiff of ignited wisp of dry grass, and the breathtaking magnificence of caterpillars at feed. The actual taking of larvae at night requires some dexterity for whereas some may wait your plucking them between finger and thumb, most will curl and drop as prolonged light shines upon them. Where space allows it is prudent to cup the haddbelow, while the problem of standing your lamp on an even keel to free both hands is not always easy. Even transferring your larvae to a box is not that simple in the dark, the more so if earlier captures are ready to escape.

Larvae can be collected by the picking of flowers, seed-pods or cones, and these will generally yield one species, at least at any one time of year. Pugs, pod-lovers (Coronet etc..) and Rivulets are good instances of larvae to be had in this way, but sallow catkins will produce several species (of the autumnal noctuids) as will poplar catkins, wychelm flowers, Compositae seedheads. Material so gathered should be hung for a few days in large cloth bags such as old pillow cases of larger, and then turned out when larvae are found to be sitting on the side of the bag. With fully- grown species the bag can be left suspended until they have pupated. Always collect when dry.

Other larvae can be found in their more specific requirement of a stem of reed, rush, iris and other aquatic plants, some declare their presence by withered shoot but most require closer inspection.

It is good sense never to crowd larvae and if possible to keep similar ones together as they are collected. Haversacks were once made with division so that one side could carry empty boxes and the other filled, but these seem to have vanished from dealer's lists and more domestic needlework is needed. Cannibal larvae like Dunbar and Satellite will give early cause for identification and separation.

Whatever the method of collection each larva will begin to fall into place in its natural classification, first to family and then to smaller groups, when reference to standard textbooks will eliminate those confined to certain parts of Britain or time of year, or food. Small larvae will need to be reared to full growth before comparative description be made, as a good many are rather different in pattern and colour in earlier skins.

Although our contemporary textbooks tend now to high-light the omissions in knowledge of life history and early stages, the general impression given is that we know most of the species habits. This is quite untrue, much is copied from the Victorians, is dependent on species known only from captive rearing or is simple guess work. In groups like the Waves and Footmen only a handful of larvae have ever been found wild while all too often the food is said to be "low plants". There is in fact so much to be learned about even our commonest species that we could all well spend our time working with larvae alone.

Gerry HacpcJett. AN INTRODUCTION TO PYRALID MOTHS IN NORFOLK.

It is understandable that many recorders consider it to be enough of a struggle trying to identify the larger moths, without becoming involved with microlepidoptera. Nonetheless we receive a welcome and increasing number of micro records under the "other species" heading on the cards. Three of those most frequently listed are Small Magpie, Mother of Pearl and Garden Pebble. Following fruitless searches through Skinner and South for what is obviously a fairly common, average-sized moth, realisation slowly dawns that the creature we have observed does not have a place in either of the afore- mentioned works because in fact it is a member of that fascinating group of moths that seem to form a bridge between macros and micros, the Pyralids. Interest is further heightened when we discover that many of them are well-marked, some are larger than some macro species, and some even have English names!

Until quite recently the only relatively contemporary book on Pyralids was Beirne's "British Pyralid and Plume Moths", published by Wamc in the 1950s and now out of print. However in 1986 Harley Books published "British Pyralid Moths" by Barry Goater, and this outstanding work has done a great deal to provoke renewed interest and research, although it also reveals how large are the gaps in our current knowledge of these moths, especially in terms of breeding biology and national distribution.

While there are technical differences to do with structure and wing venation, two of the readily observed characteristics of most Pyralids are their relatively long legs and their habit at rest of holding the antennae back over the wings. Clearly these are generalisations and there are other features which help to differentiate the various groups. In fact the British Pyralidae are divided into twelve subfamilies of which the largest is the Phycitinae with fifty-eight species.

Perhaps the most frequently seen are some of the or grass moths. They are easily flushed during casual summer walks, but soon drop to rest again in typical pose with head held downwards and wings tightly rolled around the body. As the common name suggests many frequent grassland habitats of various kinds and most of the species that are common nationally, such as Chrysoteuchia culmella, Agriphila straminella and A. tristella, are equally abundant in Norfolk. Within this general group there are also less common species to be found here, including Calamatropha paludella in the Broads, Thisanotia chrysonuchella in the Brecks, and fascelinella, a rare moth of coastal sandhills.

Several Pyralids are likely to occur in ordinary gardens. As well as those mentioned at the beginning of this article, others we may come across frequently include olivalis, the Bee Moth - Aphomia sociella, and some members of the Scoparinae. Of course many have special habitat preferences while some have particularly interesting life histories. The larval stages of the China Marks, for example, are aquatic, feeding on various waterweeds. All four of the native species are common in this county . Certain pyrales are well-known as pests of various stored products, especially cereals. A good example is Ephestia kuehniella - the Mediterranean Flour Moth.

As with the larger moths, some species are migrants, and among those occuring regularly are Nomophila noctuella - the Rush Veneer, and Udea ferrugalis. Others are rarely seen in this country but are cause for great interest when they do arrive, such as the two specimens of Palpita unionalis which were captured at Winterton dunes in October 1988 (A. Foster, N.M.S. newsletter April 1989). There are yet others which are both migratory and resident. This applies to the Breckland moth Evergestis extimalis which also occurs as an irregular migrant. Indeed the only records of the species from our current survey both come from the east coast. The European Corn-borer Ostrinia nubilalis has established populations in some parts of southern England, but not in Norfolk. Otherwise it is quite a rare migrant and again we know of only a few records: three in 1969 and one in 1987. An interesting comparison of population expansion in the county maybe made by reference to two wetland species, cilialis and Phlyctaenia perlucidalis. Both are distinctive and easily recognised moths. The former is a very local species nationally with its headquarters in the fens of Cambridgeshire and Huntingdonshire. Although Ted Ellis makes no mention of it in his book "The Broads" (Collins, New Naturalist, 1965) there are records from the sixties onwards and it is currently well- established in this area and in other wetland habitats across the county . The larvae feed on sedges, and the question that arises is, has it increased its range or merely been overlooked in the past?

P. perlucidalis was first noted at Woodwalton Fen, Hunts. in 1951 and has since been found in other parts of the Fens and along the east coast. The first Norfolk records were from Hickling in 1974 (T.N.D. Peet, Trans. Norf. and Nor. Nat. Soc. Vol.23 part 5, 1975) with subsequent records from other broadland sites during the eighties. The larvae are stated to feed on thistle ( spp.) and presumably these would be wet-loving varieties. However over the last two years specimens have been captured over a wide spread of the county from dry habitats, frequently far from water, and including a back garden in Attleborough. This suggests that the moth might be exploiting other thistle species as larval foodplants and it will be interesting to monitor any further expansion of its range here.

There are currently 208 species of Pyralidae on the British list, of which 76 have been recorded in Norfolk, as far as we know, since our 1980 baseline. Several species known to occur here have not as yet been recorded during the present survey. This fact, coupled with our comparative lack of knowledge of much pyralid biology, should act as a spur to all those involved in recording our county's moths. I hope that this brief introduction may serve to encourage the study of this intriguing group.

Post - 1980 Checklist of Norfolk Pyralids.

Chilo phragmitella Calamatropha paludella Chrysoteuchia culmella pascuella Crambus uliginosellus Crambus lathoniellus Crambus perlella Agriphila selasella Agriphila straminella Agriphila tristella Agriphila inquinatella Agriphila latistria Agriphila geniculea Catoptria pinella Catoptria falsella Thisanotia chrysonuchella Pediasia fascelinella Platytes cerussella Schoenobius gigantella Donacaula forficella Donacaula mucronellus Acentria nivea - Water Veneer Scoparia subfusca Scoparia pyralella Scoparia ambigualis Dipleurina lacustrata Eudonia pallida Eudonia truncicolella Eudonia angustea Eudonia mercurella Elophila nymphaeata - Brown China-mark Parapoynx stratiotata - Ringed China-mark Parapoynx stagnata - Beautiful China-mark Cataclysta lemnata - Small China-mark Evergestis forficalis - Garden Pebble Evergestis extimalis Evergestis pallidata Pyrausta aurata Pyrausta purpuralis Ostrinia nubilalis - European Corn-borer Eurrhypara hortulata - Small Magpie Eurrhypara lancealis Phlyctaenia coronata Phlyctaenia perlucidalis Anania verbascalis Ebulea crocealis Nascia cilialis Udea lutealis Udea prunalis Udea olivalis Udea ferrugalis Nomophila noctuella - Rush Veneer Pleuroptya ruralis - Mother of Pearl Palpita unionalis Hypsopygia costalis - Gold Triangle Synaphe punctalis Orthopygia glaucinalis Pyralis farinalis - Meal Moth Aglossa pinguinalis - Large Tabby Endotricha flammealis Galleria mellonella - Wax Moth Achroia grisella - Lesser Wax Moth Aphomia sociella - Bee Moth Anerastia lotella Acrobasis consociella Numonia advenella Pempelia palumbella Pempelia formosa Phycita roborella Dioryctia mutatella Myelois cribrella - Thistle Ermine Euzophera bigella Ephestia kuehniella - Mediterranean Flour Moth Homoeosoma nebulella Phycitodes binaevella

Ken Saul

MASS MIGRATION OF YPONOMEUTA EVONYMELLA (L) IN 1989: an appeal for records.

In the recent issue of Entomologist's Rec. J. Var., Col. A.M.Emmet shows that Y. evonymella (one of the Small Ermine Moths) is primarily a migrant in southern Britain. It is however, a well established resident in Wales, N.England and Scotland, where the food plant Bird Cherry (Prunus padus) is far commoner. Col. Emmet's paper (Ent. Rec. 102: 65 -68) records an influx of large numbers of Y. evonymella in July of last year, from localities ranging from Essex to Cornwall, with the largest invasions being noted on the nights of 6/7th. July and 9/10th. July 1989. It is assumed the moths originated from the continent.

Upon checking over note books for 1989 Ken Saul and myself found that we had also made note of a large influx of those moths on the nights of 6/7th. July and 7/8th. July from Burgh Common and Brundall respectively. Thus extending the known range of the migration further north than previously published.

Col. Emmet has suggested that a supplementary article on this Norfolk influx be submitted to the Ent. Rec. for publication later in the year. I would, therefore, be very interested to hear if anyone else also noted large numbers of Y. evonymella last July, particularly if sightings were further west in the county than the two observations given above. Due acknowledgement of records would, of course, be given in any resulting publication.

Andy Foster, N.C.C., 60 Bracondale, Norwich, NR1 2BE. Tele: 620558.