SV: [Syrphidae] identity

[Graham Rotheray]

Some folk have been in touch about rat-tails in syrphids following the recent Graptomyza discussion.  I hope the following explains a bit more about this interesting feature although, of course, my interpretations may be wrong.

Over and above the Eristalini, elongate anal segments in larvae are common within and between several Eristaline lineages including Eumerus eg obliquus and Cheilosia eg alaskensis, morio etc.  However, the way in which the anal segment extends varies from group to group.  Only in Eristalini does the 'classic' long or rat tail consist of the anal segment divided into three sections with the first two sections elongate compared with the much shorter third or terminal section.  

In Blera, Caliprobola and Lejops it is the reverse with the third section elongate compared with the very little elongated basal two sections.  In Xylotines the three sections tend to be extended equally.  It Chrysogasterines all three sections are elongate but the third much more than the first two.  In Eumerus, Cheilosia and Volucellines such as Graptomyza and Copestylum the anal segment consists of only two sections.  As Chris mentioned, in several Copestylum species groups, one or other or both sections are elongate.  In  Eumerus and Cheilosia it is the terminal section that is longer than the first.   

In Portevina, Temnostoma and within several species groups of Cheilosia and Copestylum the anal segment has gone in the other direction and retraction has occurred.  The extreme state is a flattened and disc-like anal segment eg Portevinia maculata.  Such a shape is associated with larvae tunnelling in dense or fairly solid material and this shape seems to protect the posterior respiratory openings from becoming blocked with tunnel debris.

In Microdontines and Syrphines elongate anal segments are unknown, probably because the anal segment became modified for locomotion early in the evolution of these groups.

Best wishes to all,

Graham

Dr Graham E Rotheray, Curator of Insects,
National Museums of Scotland, Chambers Street,
Edinburgh EH1 1JF Tel +44 (0)131.247.4243 
Fax +44 (0)131.220.4819

-----Original Message-----
From: syrphidae-bounces at lists.nottingham.ac.uk [mailto:syrphidae-bounces at lists.nottingham.ac.uk] On Behalf Of christian thompson
Sent: 01 June 2006 14:13
To: syrphidae at lists.nottingham.ac.uk; heikki.hippa at nrm.se; bwakkie at syrphidae.com
Subject: Re: SV: [Syrphidae] identity

Very interesting, Heikki:

This as Graham Rotheray will tell you parallels the development in New World Copestylum where a number of species have developed long (rat)-tailed maggot forms and in live in phytotelmata, such as bromeliads, etc.

There is also another common Graptomyza in Australia and the Solomons which has been collected around out-door privies. So, I suspect it may be like Ornida and breed in them.

Oh, well ...

So many interesting flower flies, so little time.

Cheers

F. Christian Thompson
Systematic Entomology Lab., USDA
c/o Smithsonian Institution
MRC-0169 NHB
PO Box 37012
Washington, DC 20013-7012
(202) 382-1800 voice
(202) 786-9422 FAX
cthompso at sel.barc.usda.gov e-mail
www.diptera.org  web site

>>> heikki.hippa at nrm.se 06/01/06 08:12AM >>>
Dear Bastiaan, Thomas, Andrew and others,

The species is not dissimilar to one which was collected by Thomas Romig, also by me, in Malaysia. What is interesting with that species is the larva. It is rat-tailed like in Eristalini and lives inside bamboo stems on which woodpeckers or other animals have made holes. I have a few of these larvae at me and have intended to describe them, but it has not been done.

Best wishes, Heikki

Ursprungligt meddelande-----
Från: syrphidae-bounces at lists.nottingham.ac.uk [mailto:syrphidae-bounces at lists.nottingham.ac.uk]För Bastiaan Wakkie
Skickat: den 29 maj 2006 12:03
Till: Hoverfly discussion list
Ämne: [Syrphidae] identity


  Hi all,

  I received this beautiful photo of a Syrphid but have no clue what family it even is. Anyone?
  The photo is taken in Indonesia.

  Thanks, 

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