Hoverfly Newsletter Number 51 Autumn 2011
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Dipterists Forum Hoverfly Newsletter Number 51 Autumn 2011 ISSN 1358-5029 This newsletter went to press shortly before the start of the 6th International Symposium on the Syrphidae, scheduled to take place in Glasgow from 5-8 August 2011. A review of this very important event will appear in the next newsletter. Most readers will no doubt first see this newsletters, as with other issues, when it arrives by post attached to the twice-yearly Dipterists Forum Bulletin. In that copy any colour images will appear in black and white. However the newsletter should be available sometime later as a pdf., with full colour, on the Forum’s website, and in due course it will be available along with previous issues on the Hoverfly Recording Scheme website. If any readers wish to receive this newsletter in the colour pdf. version as an email attachment, would they please let me know. Articles and illustrations (including colour images) for the next newsletter are always welcome. Copy for Hoverfly Newsletter No. 52 (which is expected to be issued with the Spring 2012 Dipterists Forum Bulletin) should be sent to me: David Iliff Green Willows, Station Road, Woodmancote, Cheltenham, Glos, GL52 9HN, (telephone 01242 674398), email:[email protected], to reach me by 20 November 2011. The hoverfly illustrated at the top right of this page is Sphegina clunipes. ________________________________________________________________ have covered costs at the price we advertised. A final Hoverfly Recording Scheme RRP has yet to be announced, but it will probably have to Update - Summer 2011 be in excess of £20 so the advance purchase price of £14+ £2p&p looks pretty good. Stuart Ball 255 Eastfield Road, Peterborough, PE1 4BH, [email protected] Much of the last year has been taken up by the Roger Morris WILDGuide. We are extremely pleased with the way the 7 Vine Street, Stamford, Lincolnshire, PE9 1QE, book looks and are certain that it will represent an [email protected] important advance. It has been designed to be a companion to Stubbs and Falk as well as to provide an This has been one of the busiest years we can remember introduction that can be used by the relative novice. In and 2011 promises to be a bumper year for the scheme. addition to a huge number of excellent photographs of By the end of the year there should be a considerable live flies, we spent a significant part of the winter number of new hoverfly products on the bookshelves and photographing critical features so that species accounts available electronically. They include a new Provisional could be populated with taxonomically relevant Atlas, the long-awaited Status Review and of course the illustrations. We had hoped that the book would be WILDGuide to Britain's Hoverflies. In addition, the first printed in time for the 6th International Symposium on the major conference on the Syrphidae in Britain will have Syrphidae in Glasgow (5-8 August 2011) but in the end taken place in Glasgow in early August. At the time this the job proved too much for us and there has been note was written there were 58 confirmed bookings for slippage. We now think that it will be out sometime in the the symposium and it is anticipated that the final total will autumn - probably November. ultimately reach 80 hoverfly enthusiasts from across the world. The atlas will be printed by the end of July but the print run will be short as we just don't have the money to print a We have taken just over 100 advanced bookings for the large number. We will provide copies to those recorders WILDGuide and are very grateful for this. It is likely to who have provided significant numbers of records (set at be a very good deal for those who have done so because 75 or more records in the past ten years which suggests the RRP of the guide is likely to be a fair bit more than we contributors who are actively recording hoverflies). The had expected. Unfortunately, the price the publishers get Biological Records Centre at Wallingford has kindly from on-line bookshops is so poor that they would not Hoverfly Newsletter # 51 Page 1 Dipterists Forum agreed to include this atlas in their series, thus giving it an One episode earlier this year is illustrative. This involved ISSN; and they will deal with the mailout to contributors. a specimen that was posted on one of the continental This is an immense relief to us as we are finding it websites proposing two identities within different groups difficult to raise the funds we need to support this project. of Cheilosia - one in the variabilis group and the other in We hope that the atlas will be available as a pdf on the the bergenstammi group (using the definitions in Van HRS website but this possibility has still to be resolved. Veen rather than Stubbs & Falk). This combination alone suggests that critical characters had not been taken into The hoverfly atlas will form part of the delegates' pack for account and the authors were wildly stabbing at the Glasgow symposium. This is because we approached identifications. Continental observers confirmed the the country conservation agencies and the major societies record within the bergenstammi group but Roger was not for support for this as part of the Glasgow symposium convinced. In the end, advice from Martin Speight to package. Dipterists Forum, BENHS, Glasgow Natural Roger put this species into the grossa group. It History Society and the Malloch Society have all provided highlighted the need to interpret keys carefully as the financial help. Regrettably, none of the Country Agencies specimen had vague but detectable dark marks on the hind could support what might be regarded as a good example tibiae, but the final identity made sense. Two weeks later, of 'the big society' in action; nor were any of the largely Roger took a specimen that bore similar features and professional societies such as the RES willing to support recognised it immediately! the symposium; several failed to even answer our letter. This is very disappointing given that hoverflies have a This episode generated a further lesson. Roger entered high profile in conservation management initiatives and as into correspondence with the recorder who posted the pollinators; which is a matter of widespread ecological photograph and gave subsequent advice on a small dark concern. It is one of the key reasons behind our species that might (or might not) have been a Pipizella. difficulties funding the atlas. Several e-mails later had the recorder suggesting, variously, 'something close to Triglyphus primus', Pipiza The atlas has led to a significant jump in the number of luteitarsis and finally Pipizella maculipennis on the basis records on the Recording Scheme database. The atlas we that they thought they could detect black hairs on the produced in 2000 drew upon 375,000 records and was hypopygium - RM could not see them! The fore tarsi were remarkable for its time. This new atlas is based on only partially yellow and so P. luteitarsis should never 720,000 records on the HRS database and has access to have been suggested! The choice of Pipizella another 25,000 records on the NBN already. This maculipennis suggested that the author had not bothered increase includes 210,000 records since the year 2000. to think about what could be seen and what needed The data show a variety of important trends, and highlight microscopic identification. Further investigation revealed just how many hoverflies have undergone significant that they were using those keys by Van Veen that were declines over the past 25 years or more. If the same available on the internet and were often running to non criteria as used for birds were applied to hoverflies, over British species as options! This experience highlights the 30% of the British fauna would have to be listed as a need to follow a sequence of rational thinking that should Biodiversity Action Plan species. The other major trend be used to get to a correct identification: that is emerging is the loss of recorders who have the confidence and competence to tackle difficult taxa. To which Tribe does the specimen belong? If Recording using photography is also taking over from this cannot be determined with confidence then traditional collection of specimens and this means that the photo can be taken no further. some of the trends are likely to have been significantly Can the specimen be taken to genus? If not it influenced by recorder effort. Part of this shift has cannot be given a name. happened because we have actively harvested data from At the generic level, are the features described in websites. These recorders have not sought to submit the key properly exposed? If so can the species records but have generated substantial blocks of data that be tentatively ascribed to a species? If not it are useful to the scheme. should be taken no further. Once a specific identification has been We can make allowances for changing recorder trends determined, check the species account and provided the core of records come from established and decide whether this is a viable option. competent recorders. At the moment just ten recorders Remember that the safest rule of thumb is that have contributed 35% of the records on the database and specimens will normally run to a common 50% of the data have been supplied by a pool of 21 species. If your identification immediately runs recorders. the remainder has been supplied by around to the rarest species in the genus or to 1400 recorders over the entire span of records.