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

DOI:10.11646/zootaxa.2043.1.1
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Verner Michelsen at University of Copenhagen
Verner Michelsen
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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 fly reproducing parthenogenetically.
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ZOOTAXA
Revision of the willow catkin flies, genus Egle
Robineau-Desvoidy (Diptera: Anthomyiidae),
in Europe and neighbouring areas
VERNER MICHELSEN
Magnolia Press
Auckland, New Zealand
2043
MICHELSEN
2 · Zootaxa 2043 © 2009 Magnolia Press
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
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© 2009 Magnolia Press
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other than private research use.
ISSN 1175-5326 (Print edition)
ISSN 1175-5334 (Online edition)
Accepted by J. O'Hara: 14 Jan. 2009; published: 16 Mar. 2009 3
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Copyright © 2009 · Magnolia Press
Zootaxa 2043: 1–76 (2009)
www.mapress.com/zootaxa/
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: vmichelsen@snm.ku.dk
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
MICHELSEN
4 · Zootaxa 2043 © 2009 Magnolia Press
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 fly 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 insect 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.
... Their larvae feed on the seeds while their imagos feed on the pollen and nectar. The adult flies play an important role as pollinators of willows (MICHELSEN, 2009). With the exception of Egle concomitans (Pandellé, 1900) which is dependent on Aspen and Poplar, adult willow catkin flies have a typical head with conspicuously protruding mouth edge and long and slender proboscis. ...
... With the exception of Egle concomitans (Pandellé, 1900) which is dependent on Aspen and Poplar, adult willow catkin flies have a typical head with conspicuously protruding mouth edge and long and slender proboscis. In addition they have a very short antennal postpedicel, an antennal arista with very short pubescence, a mid tibia without anteroventral seta and a hind tibia without apical posteroventral seta (MICHELSEN, 2009; VAN ERKELENS, 2011). Up to now ten species of willow catkin flies were reported from the Netherlands (BEUK et al., 2002;VAN ERKELENS, 2013) and eight species (including Egle brevicornis (Zetterstedt, 1838)) were reported from Belgium (GOSSERIES & ACKLAND, 1991;MARTENS & MORTELMANS, 2013;MARTENS et al., 2015). ...
... Egle brevicornis resembles the very common species Egle ciliata and the hardly recorded species Egle anderssoni Michelsen, 2009. The most important characteristics to distinguish Egle brevicornis can be found in the head (in brevicornis head higher than long, parafacial parallel-sided, fronto-parafacial angle lying well behind lower parafacial margin and haustellum and palp shorter than largest diameter of the eye) and the male genitalia (MICHELSEN, 2009). In England and Denmark Egle brevicornis is mainly found on Creeping willow Salix repens, a low growing shrub found in wet and dry sand dune slacks, on acid heaths and in moorland. ...
The willow catkin fly Egle brevicornis (Zetterstedt, 1838) new for The Netherlands and confirmed for Belgium (Diptera: Anthomyiidae)
Article
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  • Dec 2019
In this paper the willow catkin fly Egle brevicornis (Anthomyiidae) is reported for the first time from the Netherlands. This species has already been reported from Belgium, but this is based on old identifications which are recently questioned by Verner Michelsen. As no old specimens are preserved, new material was collected, which confirms the presence of Egle brevicornis in Belgium.
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... Egle myricariae Grossmann, 1998. The host plant of this species is German tamarist, a woody scrub which grows on open ground along montane and subalpine streams (MICHELSEN, 2009). ...
... In fact this key contains only the UK species, but up to now with the exception of Egle concomitans, all Belgian and Dutch species are included in his work. His drawings form a good complement to the photo's of MICHELSEN (2009) and VAN ERKELENS (2013). ...
... Apart from the typical head, important diagnostic characters for adult Egle are a very short antennal postpedicel, an antennal arista with very short pubescence and a hind tibia without an apical posteroventral seta (MICHELSEN, 2009;VAN ERKELENS, 2011). ...
The willow catkin flies Egle lyneborgi Ackland & Griffiths, 2003 and Egle suwai Michelsen, 2009 new for Belgium (Diptera: Anthomyiidae)
Article
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This paper describes the first records of the anthomyiids Egle lyneborgi Ackland & Griffiths, 2003 and Egle suwai Michelsen, 2009 for Belgium. In addition a method for abdominal dissection without using aggressive chemicals is explained.
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... The adults have been recorded in April, on flowering catkins of sallow. This genus has recently been revised by Michelsen (2009). ...
A Survey of Invertebrates on Inkle Moor, Thorne, 2012 Incorporating contributions by M A Survey of Invertebrates on Inkle Moor, Thorne, 2012
Technical Report
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  • Dec 2021
Inkle Moor adjoins Thorne Moors NNR to the west. The report lists identifications of invertebrates made during a survey in 2013.
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... The Anthomyiidae family found at the time of sampling were eight individuals, which were the species of Egle sp. The majority of the larvae of this species are seed-eating, and as adults, these flies have a role as insect pollinators [21]. ...
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... Thanks to the typical head with a conspicuously protruding mouthedge and long and slender proboscis and palpae (except in Egle concomitans (Pandellé, 1900) which has Populus as host plant), the lack of an anteroventral seta on the mid tibia, the early flight period and the typical habitat, it is mostly possible to assign specimens to the genus Egle in the field. For identification to species level dissection of the terminalia is needed in most cases (MICHELSEN, 2009;VAN ERKELENS, 2011;VAN ERKELENS, 2013). The genus is recently reviewed by MICHELSEN (2009) for Europe and it's neighbouring areas. ...
Alliopsis billbergi (Zetterstedt, 1838) new for Belgium (Diptera: Anthomyiidae)
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  • Dec 2017
In this paper the Anthomyiidae species Alliopsis billbergi (Zetterstedt, 1838) is added to the Belgian checklist.
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The abdominal and pregenital segments and genitalia were studied in males of Zaphne barbiventris (Zetterstedt, 1845) and Delia fabricii (Holmgren, 1872) (Anthomyiidae). The examined species are very similar in the structure of the sclerites and muscles of their terminal segments. Differences between Delia Robineau‐Desvoidy, 1830 and Zaphne Robineau‐Desvoidy, 1830 were found only in the structure of the pregenital segments and their muscles. Delia has well‐developed and well‐identified tergite VI, while tergite VI of Zaphne is fused in syntergosternite VI + VII + VIII as indicated by the insertion of muscles of ITM 5 running from tergite V. Within members of the muscoid grade, the skeleton and musculature of male terminalia of the Anthomyiidae were similar to that in the subfamily Azeliinae of the Muscidae and the Scathophagidae. The complete set of phallapodeme muscles, as well as the complete set of muscles of the pregenital sclerites and the position of cercal muscles M 26, has shown that the Anthomyiidae have more plesiomorphic character states than other members of the muscoid grade. Descriptions and figures of the terminal sclerites and muscles of Zaphne barbiventris are provided.
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New distributional and biological records are provided for wasps in the subfamily Miscogasterinae (Hymenoptera: Pteromalidae), reared from Diptera in Scotland and northern England. Thektogaster chrysis (Förster, 1861) is added to the British list based on specimens reared from Gimnomera tarsea (Fallén) (Scathophagidae), a first host record for the genus. Rhicnocoelia constans (Walker, 1836) is reared from Loxocera sylvatica Meigen (Psilidae), the first European host record for the genus. Nodisoplata diffinis (Walker, 1874) is reared from Egle spp. (Anthomyiidae) in Salix catkins, a first host record for the genus. Ardilea convexa (Walker, 1833) is reared from an Agromyzidae on Tripolium pannonicum , a first host record for the genus.
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Supplementary material 2
Data
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  • Sep 2014
Electronic appendix 2: PDF literature references file
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The world species of anthomyiid cone and seed pests are revised. A new genus, Strobilomyia gen.n., is erected for the eighteen species, including seven new to science, presently recognized. Author's views on homologies in the male and female terminalia of Anthomyiidae and other Diptera Cyclorrhapha are amplified as background for the terminology employed. The monophyly and systematic position of Strobilomyia are discussed with reassessions of related genera: Lasiomma Stein, Chirosia Rondani, Egle Robineau-Desvoidy and Acklandia Hennig. Zoogeographic aspects, especially vicariance across the Beringia, are analysed from a partial hypothesis of phylogenetic relationships among the species of Strobilomyia in conjunction with paleo-environmental data. New generic synonyms are: Macrophorbia Malloch, Crinurina Karl, Si-nohylemya Hsue (all=Lasiomma); Acrostilpna Ringdahl, Shakshainia Suwa, Meliniella Suwa (all=Chirosia). The species recognized in Strobilomyia (with geographic range and host trees in parentheses) are: anthracina (Czerny) (Palearctic, Picea); neanthracina sp.n. (Nearctic, Picea and ITsuga); appalachensis sp.n. (E. Nearctic); melania (Ackland) (Europe, Larix); sibirica sp.n. (N.E. Europe, Siberia, Larix); viaria (Huckett) (E. Palearctic, Nearctic, Larix); infrequens (Ackland) (Palearctic, Larix); luteoforceps (Fan & Fang) (E. Palearctic, Larix); baicalensis (Elberg) (E. Palearctic, Larix); laricicola (Karl) (Palearctic, Larix); laricis sp.n. (Nearctic, Larix); macalpinei sp.n. (W. Canada, Larix); carbonaria (Ringdahl) (C. Europe, E. Nearctic, Abies); svenssoni sp.n. (N. Europe, Mongolia); suwai sp.n. (Japan); todocola (Suwa) (Japan, Abies); abietis (Huckett) (Nearctic, Abies); and oriens (Suwa) (E. Palearctic, Abies).
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