ZOOTAXA

2043

Revision of the willow catkin , genus Egle Robineau-Desvoidy (Diptera: ), in Europe and neighbouring areas

VERNER MICHELSEN

Magnolia Press Auckland, New Zealand Verner Michelsen Revision of the willow catkin flies, genus Egle Robineau-Desvoidy (Diptera: Anthomyiidae), in Europe and neighbouring areas

(Zootaxa 2043) 76 pp.; 30 cm. 16 Mar. 2009 ISBN 978-1-86977-337-3 (paperback) ISBN 978-1-86977-338-0 (Online edition)

FIRST PUBLISHED IN 2009 BY Magnolia Press P.O. Box 41-383 Auckland 1346 New Zealand e-mail: [email protected] http://www.mapress.com/zootaxa/

© 2009 Magnolia Press All rights reserved. No part of this publication may be reproduced, stored, transmitted or disseminated, in any form, or by any means, without prior written permission from the publisher, to whom all requests to reproduce copyright material should be directed in writing. This authorization does not extend to any other kind of copying, by any means, in any form, and for any purpose other than private research use.

ISSN 1175-5326 (Print edition) ISSN 1175-5334 (Online edition)

2 · Zootaxa 2043 © 2009 Magnolia Press MICHELSEN Zootaxa 2043: 1–76 (2009) ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ ZOOTAXA Copyright © 2009 · Magnolia Press ISSN 1175-5334 (online edition)

Revision of the willow catkin flies, genus Egle Robineau-Desvoidy (Diptera: Anthomyiidae), in Europe and neighbouring areas

VERNER MICHELSEN Zoological Museum, Natural History Museum of Denmark, University of Copenhagen, Denmark & Museum of Zoology, Lund University, Sweden. E-mail: [email protected]

Table of contents

Abstract ...... 4 Introduction ...... 4 Material and methods...... 5 Taxonomic history ...... 5 Monophyly and relationships...... 6 Adult habits, pollen-feeding and mouth part structure ...... 6 Immature stages ...... 8 Genus Egle Robineau-Desvoidy, 1830...... 13 The Egle concomitans section ...... 14 1. Egle concomitans (Pandellé, 1900) ...... 14 The Egle longirostris species group ...... 18 2. Egle myricariae Grossmann, 1998 ...... 18 3. Egle longirostris (Stein, 1907) ...... 20 The Egle brevicornis section ...... 21 The Egle brevicornis species group ...... 23 4. Egle ciliata (Walker, 1849) ...... 23 5. Egle brevicornis (Zetterstedt, 1838)...... 25 6. Egle anderssoni sp. nov...... 27 The Egle pilitibia species group ...... 30 7. Egle pilitibia (Ringdahl, 1918) ...... 30 The Egle minuta section ...... 33 8. Egle atomaria (Zetterstedt, 1845) ...... 33 The Egle steini species group ...... 35 9. Egle parvaeformis Schnabl in Schnabl & Dziedzicki, 1911...... 35 10. Egle steini Schnabl in Schnabl & Dziedzicki, 1911 ...... 37 11. Egle ignobilis sp. nov...... 39 12. Egle inermis Ackland, 1970 ...... 40 13. Egle inermoides sp. nov...... 43 14. Egle groenlandica sp. nov...... 44 The Egle setiapicis species group ...... 45 15. Egle setiapicoides sp. nov...... 45 The Egle subarctica species group ...... 47 16. Egle subarctica (Huckett, 1965) ...... 47 17. Egle subarcticoides sp. nov...... 49 The Egle rhinotmeta species group ...... 50 18. Egle rhinotmeta (Pandellé, 1900) ...... 51 The Egle minuta species group ...... 53

Accepted by J. O'Hara: 14 Jan. 2009; published: 16 Mar. 2009 3 19. Egle minuta (Meigen, 1826) ...... 53 20. Egle parva Robineau-Desvoidy, 1830 ...... 56 21. Egle lyneborgi Ackland & Griffiths, 2003 ...... 58 22. Egle suwai sp. nov...... 69 Identification key to male and female Egle of Europe and neighbouring areas ...... 69 Acknowledgements ...... 72 References...... 72

Abstract

Egle Robineau-Desvoidy is a modest-sized genus of small blackish anthomyiids with a Holarctic and northern Oriental distribution. They are univoltine, interacting closely with the host plants of their seed-feeding larvae, mainly species of willow (Salix), but also poplar (Populus) and false tamarisk (Myricaria) support some species. Summaries are given of adult and larval habits based on published and new observations. Adult mouth part structure in relation to pollen feeding is treated in some detail. A taxonomic revision with illustrated descriptions and an identification key to males and females is given for all known West Palearctic species and a few more from Greenland and Central Asia. Seven new species are described: Egle anderssoni, E. ignobilis and E. suwai from Denmark and Sweden, E. inermoides from Spain, E. groenlandica from Greenland, E. setiapicoides from Uzbekistan, and E. subarcticoides from Israel. Egle polychaeta Griffiths, 2003 is considered identical with E. steini Schnabl, 1911 (syn. nov.). Egle groenlandica sp. nov. is only known from females and may be the first known case of a calyptrate reproducing parthenogenetically.

Key words: Diptera, Anthomyiidae, Egle, new species, Europe

Introduction

Anthomyiids of the genus Egle are univoltine, with a flight period closely synchronized with the period of flowering and seed development of their hosts. All species apparently have seed-feeding larvae with a narrow host range. At the same time the adult flies tend to serve as specialized pollinators of their larval hosts that are, with few exceptions, species of willow (Salix spp.). Accordingly, most species of Egle are active from the very beginning of the season and among the first calyptrate flies to emerge from overwintering puparia. They can easily be observed and collected, often in large numbers, on and around shrubs of flowering willow. Even so, the genus is very poorly understood in respect to taxonomy and life history. One reason could be that these often small to minute, darkish anthomyiids are largely deprived of external diagnostic characters and thus often impossible to identify without terminalia dissection. On top of this, dry-mounted specimens often suffer from shrinking and distortions due to their relatively thin cuticle. The present paper attempts to upgrade taxonomic knowledge about the fauna of Egle species occurring in Europe and adjoining landmasses. Seven new species are described and a serious attempt is made to identify and match females with males for all species. One should keep in mind though that the genus, due to its early- season occurrence, is badly underrepresented in collections of Anthomyiidae. More collecting, especially in less accessible parts of the region, will certainly bring additional new species to light. The Egle–Salix interrelationship is only one among many components of the intricate miniature ecosystem formed by the male and female inflorescences of willow and their diverse community (Urban & Kopelke 2004). Still, it embraces several basic ecological topics such as mutualism, resource partitioning, coexistence and competition. It is my hope that the present paper will prove helpful to community ecologists and others interested in the multi-faceted interactions between Egle species and their willow hosts. Especially the observation that an amazing diversity of Egle species often occurs together in suitable localities, all apparently with larvae exploiting the same host resource, simply calls for investigations of the underlying mechanisms.

4 · Zootaxa 2043 © 2009 Magnolia Press MICHELSEN