Transactions of the Norfolk and Norwich Naturalists' Society
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Z*U BRITISH MUSEUM (NATURAL HISTORY) 3 J AUG 1993 TRANSACTIONS EXCHANGED of GENERAL LIBRARY THE NORFOLK & NORWICH NATURALISTS 5 SOCIETY Vol. 29 Part 5 (July 1993) : TRANSACTIONS OF THE NORFOLK AND NORWICH NATURALISTS’ SOCIETY ISSN 0375 7226 Volume 29 Part 5 (July 1993) Editor P. W. Lambley OFFICERS OF THE SOCIETY 1993-1994 President: M. J. Seago Vice-Presidents: Dr. R. Baker, P. R. Banham, A. L. Bull, K. B. Clarke, E. T. Daniels, D. A. Dorling, K. C. Durrant, R. E. Evans, R. Jones, Mrs J. Robinson, M. J. Seago, F. J. Taylor-Page. Chairman: D. A. Dorling, St. Edmundsbury, 6 New Road, Hethersett, NR9 3HH. Secretary: Dr. A. R. Leach, 3 Eccles Road, Holt, NR25 6HJ. Assistant Secretary: Mrs J. Negal, ‘Inishmore’, Newton Flotman, NR15 IQS. Treasurer: D. I. Richmond, 42 Richmond Rise, Reepham, NR10 4LS. Assistant Treasurer: R. Haney, 124 Norwich Road, Taverham, NR 6QH. Membership Committee: Mrs A. Brewster (Chairman), C. Dack ( Secretary). Programme Committee: Miss J. E. Smith (Chairman), Mrs C. Haines (Secretary). Publications Committee: R. Jones (Chairman), P. W. Lambley, M. J. Seago, R. Haney (Editors). Research Committee: P. Banham (Chairman), E. Cross (Secretary). Hon. Auditor: J. E. Timbers, 68 New Road, Hethersett. Elected Members of Council: (Retiring 1994): Mrs M. Cooper, Dr. R. Hammond, C. Neale. (Retiring 1995): F. Farrow, D. E. Mower, M. Poulton. (Retiring 1996): N. S. Carmichael, J. G. Goldsmith, B. Sage, M. D. Smith. Co-opted and Representative Members of Council: A. G. Irwin (Museum), Dr. W. Sutherland (University), J. Lewis (Norfolk Naturalists Trust), P. W. Lambley (English Nature). REFEREES OF PRINCIPAL SPECIALIST GROUPS Birds (Editor of the Report) M. J. Seago, 33 Acacia Road, Thorpe St. Andrew, Norwich NR7 OPP. Mammals (Editor of the Report): R. Haney, 124 Fakenham Road, Taverham, NR8 6QH. Bats: J. G. Goldsmith, Castle Museum, Norwich NR1 3JU. Amphibia & Plants: A. L. Bull, “Hillcrest”, East Tudenham, Dereham (East Norfolk) Mrs G. Beckett, Bramley Cottage, Stanhoe, King’s Lynn PE31 8QF (West Norfolk). Mosses & Liverworts: C. R. Stevenson, 1 1 1 Wooton Road, King’s Lynn. Algae: K. B. Clarke, Decoy House, Browston, Great Yarmouth Fungi: R. E. Evans, “Chantrelle”, Church Road, Welborne, Dereham. Insects: K. C. Durrant, 18 The Avenue, Sheringham, NR26 8DG. Mollusca: R. E. Baker, 25 Southern Beach, Mulbarton, NR14 8BU. Marine: Dr. R. Hamond, Scaldbeck, Morston, Holt, NR25 7BJ. Freshwater: R. J. Driscoll, Castle Museum, Norwich, NR1 3JU. Photography: R. Robinson, 5 Southern Beach, Mulbarton, NR14 8BU. FRONT COVER: Leaves of Black Poplar Populus nigra ssp. betulifolia (see p. 375) P.W. Lambley THE CHANGING STATUS OF INSECTS IN NORFOLK THE PRESIDENTIAL ADDRESS DELIVERED TO THE SOCIETY ON 3 FEBRUARY 1993 A. G. Irwin Castle Museum, Norwich NR1 3JU Ladies and Gentlemen - The honour of being elected President of this Society must always be tem- pered with the knowledge that sooner or later an Address should be delivered. In contemplating this prospect, I expect I was not the only President to think of a title before knowing exactly what I was going to say! So I gave our programme secretary a suitably broad title - the Changing Status of Insects in Norfolk - in the hope that when the time came, I would be able to think of some way of ful- filling the expectations of the audience. How I have regretted that title! Why couldn't I have suggested "the Changing Status of Earwigs in Norfolk" or "the Changing Status of Flies in my Front Room over the last ten years"? In my journey through the literature, almost everywhere I encountered evi- dence of the changing status of insects in Norfolk. So much so that it was refreshing to find examples of species which had not changed! My problem was to choose from so many examples those which best illustrate the processes that bring about changes in our fauna. The status of an insect encompasses several elements. Firstly does it, or does it not occur in the county? If it occurs in the county, does it breed here, or is it just an occasional visitor, perhaps from overseas? If it does breed here, does it do so regularly, so that resident populations can be identified? Are those popula- tions widespread, or are they localised? Are the populations large, or are they small? How long have those populations been established, and how much longer will they survive? Of all these elements, only the last is a matter of opinion. All the others are matters of fact. Yet the status of an insect can change dramatically even though it's living now just as it has for the last ten thousand years. How? - It can be dis- covered! One moment a tiny beetle is pushing its way through a sticky patch of North Norfolk shingle, the next it is sieved, spotted, tubed, dispatched, carded, identified and published - " Bibloplectus minutisstmus new to East Anglia" (Irwin, 1983). Such a short step from oblivion to fame! As much as anything, recorded status is perceived status. Indeed our perception of an insect's abun- dance is primarily a reflection of how readily it comes to our attention. Plagues of locusts, fleas, wasps, hoverflies, ladybirds or aphids have always hit the head- lines. How many of you remember the lupin aphid? Were it not for the spectacu- lar way it affected wild and cultivated lupins (Ellis, 1983), its arrival in this coun- try might have passed unnoticed. It would be foolhardy to document changes to the status of most small insects by comparing old accounts in the literature with what we know today. Most groups were little understood, and the available identification works were incomplete and unsatisfactory, if not misleading or downright wrong. There were exceptions, however. In 1829 a list of Norfolk beetles by Robert Wigham contained 75 species, of which 17 were in the family Pselaphidae. This is not an indication that Norfolk was particularly rich in these beetles, though it does have 33 of the 51 British species. Rather, it marks the friendship that Wigham had Trans. Norfolk Norzuich Nat. Soc. 1993 29(5) 345 . with Henry Denny, who wrote the first monograph on this group just before Wigham's list was published (Denny, 1825). Most of Wigham's entries are sim- ply annotated "Norfolk", so they are of little use in evaluating the past distribu- tion of species within the county. This hardly matters in the case of the pse- laphids, for at one to two millimetres long they are among the most easily over- looked of Norfolk beetles, and our present knowledge of their distribution is sketchy, at best. It is with the more easily observed, and more easily recognised, insects that we can rely upon the observations of earlier naturalists and upon our own knowl- edge of the species, to judge whether a change in status has occurred. Butterflies, moths, crickets and dragonflies are more likely candidates for study. County sur- veys (Hall, 1991; Milford and Irwin, 1990; Richmond and Irwin, 1991) during the last ten years provide an excellent baseline from which to resurvey the county in the future, and also to look back forty, one hundred or even three hundred years ago. Sir Thomas Browne was a Norwich doctor, who has provided us with a wonderful glimpse of seventeenth century Norfolk. In his notes (Browne, 1662) he mentions that "the Gryllotalpa or fencricket comon in fenny places butt wee haue met with them also in dry places dunghills and church yards of this citty" In 1834, the Paget brothers in their Natural History of Yarmouth note that the mole-cricket " occurs at Caister; occasionally" . Thomas Southwell, commenting on Browne's letter in 1901, says "the mole-cricket ... is rare with us", while Edwards in the Victoria County History of 1901 suggests "that grand insect ... will probably prove - to be generally distributed if properly searched for" , but he only cites one locality Stoke Holy Cross. In 1921, Henry Thouless recorded an 1862 specimen from " Castleacre and notes that several specimens were brought to me some years ago from Shottesham Common." No later authenticated records are known from Norfolk, and the species is now regarded as extinct in this county. Nationally the mole- cricket was widespread and common until the extensive drainage and improve- ment of pasture in the 17th and 18th centuries, was local in the 19th century and vanished from most areas by 1950 (Marshall & Haes, 1988). It survives in a very few sites in Southern England. Unfortunately this tale of a common insect becoming more local, less abun- dant and eventually extinct is not unusual. The large marsh grasshopper was found locally across Norfolk wherever its habitat of quaking bog occurred. In the early 19th century, the Pagets (1834) recorded it as common at Belton Bog, and Wigham (1829) noted it at Horning. Until 1939, it still occurred in the Broads, but recent searches there, and in West Norfolk at Wolferton where it was last seen in 1968, have proved unsuccessful (Richmond and Irwin, 1991). Elsewhere this grasshopper can still be found in most of its former haunts in South-west England and Western Ireland (Marshall & Haes, 1988). The species can survive in quite small areas, so evidently some change of character in the quaking bogs of East Anglia has rendered them unable to support it any longer. Among the flies, only those species which are noticeable and easily recog- nised should be subject to this retrospective investigation. Outstanding among the British fauna is a yellow and black robber fly, Asilus crabroniformis, which was " well known to the Pagets (1834), who note fields, Fritton; sometimes common" In 1915 Morley and Atmore recorded it from Holme and "scarce about King's Lynn" It should be remembered that until the First World War, most fieldwork 346 .