Natural England Commissioned Report NECR234 A Provisional Assessment of the Status of Calypterate flies in the UK Calypterate First published 30th August 2017 www.gov.uk/natural -england Foreword Natural England commission a range of reports from external contractors to provide evidence and advice to assist us in delivering our duties. The views in this report are those of the authors and do not necessarily represent those of Natural England. Background This report should be cited as: Making good decisions to conserve species should primarily be based upon an objective FALK, S.J, & PONT, A.C. 2017. A Provisional process of determining the degree of threat to Assessment of the Status of Calypterate flies in the survival of a species. The recognised the UK. Natural England. Commissioned international approach to undertaking this is by Reports, Number234 assigning the species to one of the IUCN threat categories. This report was originally commissioned to update the threat status of some calypterate fly families. It is based on text originally submitted in 2005-12, but subsequently updated a number of times, most recently in late 2016. It provides a valuable repository of information on many species and should act as a springboard to further survey and work. Reviews for other invertebrate groups will follow. Natural England Project Manager - David Heaver, Senior Invertebrate Specialist [email protected] Contractor - FALK, S.J, & PONT, A.C Keywords - Diptera, true flies, house flies, bluebottles, flesh flies , invertebrates, red list, IUCN, status reviews, IUCN threat categories, GB rarity status Further information This report can be downloaded from the Natural England Access to Evidence Catalogue: http://publications.naturalengland.org.uk/ . For information on Natural England publications contact the Natural England Enquiry Service on 0300 060 3900 or e-mail [email protected]. This report is published by Natural England under the Open Government Licence - OGLv3.0 for public sector information. You are encouraged to use, and reuse, information subject to certain conditions. For details of the licence visit Copyright. Natural England photographs are only available for non commercial purposes. If any other information such as maps or data cannot be used commercially this will be made clear within the report. ISBN 978-1-78354-435-6 © Natural England and other parties 2017 This Assessment covers the following fly families: Anthomyiidae Calliphoridae Fanniidae Hippoboscidae Muscidae Nycteribiidae Oestridae Rhinophoridae Sarcophagidae 1 Table of Contents 1. Species listed by provisional status category.................................................................... 12 2. Taxonomic list of species previously assigned a conservation status but now excluded from this Assessment. ....................................................................................................... 19 3. Taxonomic list of Provisional Red Data Book and Nationally Scarce species ................ 19 4. Easy access table of the Provisional Status categories ..................................................... 26 5. Format of the data sheets .................................................................................................. 39 Information on the data sheets .......................................................................................... 39 The data sheets .................................................................................................................. 41 6. Acknowledgements......................................................................................................... 236 7. Index ............................................................................................................................... 253 2 1. Introduction to the Provisional Status Assessment Series. This report is one of a new set dealing with the status of the lesser known and less well-recorded invertebrates in the UK. The series aims to draw together and share what is known about such species, very much with a view to spurring on further interest in and recording of them. These volumes are complimentary to the Species Status Review Series which, by its very nature, covers groups with robust data sets, amenable to scrutiny through the lens of the IUCN threat categories, and with a more comprehensive understanding of both distribution and ecology. It is hoped that in drawing together the available information on the status of their species, the new Assessments will encourage greater consideration of the species needs both by those charged with their conservation and with those engaged in recording their distribution and numbers. The bulk of the text for this volume is now somewhat historic (2005-2012), although has had some minor re-evaluation and text updates until April 2017. Readers should therefore be aware of this when using this work. Use of the Assessment The use of IUCN terminology allows us to classify, describe and communicate information about the status of individual species. We have added the prefix p to indicate that this is very much a provisional assessment based on data which would be insufficient for a formal IUCN status review. As the two sorts of assessment are not equivalent, care needs to exercised in their appropriate use. The scarcer (under our current understanding) species have been given a provisional status category. When using these Provisional status classes, they should be reported in the form of “pVulnerable” to make it clear that is does not have the same footing or authority as an IUCN- compliant judgement of “Vulnerable” found in modern Species Status review series. The weighting given to the taxa in this volume in areas such as environmental impact assessment or community conservation value must be similarly moderated down, and a lower conservation class value applied in the calculation of quality scores. Suggested date for re-assessment: 2025. 3 2. Introduction to the Assessment of the status of the Calypterate flies What are Calypterate flies? Readers may be familiar with some of them by their common English names such as blow flies, bluebottles, flesh flies, though these group names hide much ecological variety and interest within the genera and species, and are sometimes only applicable to sections of a family. Although regarded by some Dipterists as "boring" in appearance, the Calyptratae include several of the most important flies in the medical, veterinary and agricultural fields, as well as many species that have specialized requirements. The latter are increasingly recognised as having potential as indicators of ecological continuity and hence are associated with high quality conservation sites. They are also worthy of conservation attention in their own right, and it is hoped that this Assessment will assist with raising their profile in this regard. Does this cover the whole group? The present volume deals with some of those species which were listed but not provided with Data Sheets by Falk (1991) for the Cyclorrhapha Calyptratae, which total 1040 under the 2015 Diptera checklist. The Cyclorrhapha Calyptratae comprise eleven families (nine of which are represented in this Assessment, the exception being the Rhinophoridae), the species included representing approximately 15% of our Diptera fauna. However, rather than continue with the same family grouping in the new Assessments, it was decided to remove both the tachinid and scathophagid fly families from this Assessment and hope that they can develop their own volumes. It is hoped, that over time and with increases in recording, both families will then be able to be subject to a full and formal IUCN Species Status Review. Some species that are included by Shirt (1987) and Falk (1991) have been excluded from the present Assessment. Four of them are judged to be neither scarce nor threatened enough to be included: Muscidae Phaonia atriceps (Loew) Phaonia siebecki Schnabl Thricops innocuus (Zetterstedt) Sarcophagidae Sarcophaga africa (Wiedemann) Why have these families not been subject to an IUCN Species Status Review? The placement in an Assessment or a Review comes down largely to whether one can muster enough records together in one place to allow a dual period comparison. Whilst it is not unknown, especially in the absence of the recording scheme, to have widely scattered records, it is more often the case that the records do not exist in the numbers required to make a meaningful comparison between the two time periods , and for species ending up having more “Data Deficient” ascriptions than is (probably) really the case. With a larger, multi-family assessment, it is quite conceivable that some families might be able to “break away” and be subject to their own Species Status Reviews if these Assessments, advances in keys, and the establishment of schemes help build up their record dataset. How were the provisional status ascriptions arrived at? 4 Unlike the formal IUCN Species Status Review reports which are founded on a data table demonstrating hectad or tetrad count changes between defined time periods, these Assessment rely on specialist opinion. This is a direct reflection of the amount of data held for most of these species. Some of the opinions on particular flies will, of course, prove to be accurate and long-standing, and others will not: only an increase in available data will improve accuracy. The IUCN category labels are used so as to avoid creating of a new, untested hierarchy, the