The Society for the study of flies (Diptera)

Good call

If you are recording in Surrey (VC17) please send me your plant gall records - diptera or not. Happy to help with identification.
jaapiella@yahoo.co.uk
Regards
Scotty

The pictures seem not to have uploaded.

I have tried again.

This is consistent with my capture of a Urophora cardui at that location on 2-vii-2009.

Another plant gall which seems to be caused by Diptera.  I found this remarkably coloured leaf of Sonchus arvensis, the Field Sow Thistle, on damp peat near a fen in Oxon.  From the reference book, the purple blisters seem to have been produced by the larvae of the Cecidomyiid fly Cystiphora sonchi.  Unfortunately no larvae were present when I collected the leaf, but the exit holes from the blisters could be seen on the underside of the leaf (third photo).
Anybody else seen such a weird, brightly coloured leaf?
Judy

Here are galls caused by a Platypezid fly on the underside (pore layer ) of a bracket fungus, Ganoderma applanatum.  This is a hard, woody, perennial bracket fungus found on dead wood or dying trees.  The creamy white pore layer can have few to numerous 'pimple' like structures within which the larvae of Agathomyia wankowiczii live.  After feeding on the fungal tissue in the gall, the mature larvae exit from the point of the gall and pupate in the soil under the bracket.
Last year I collected some of the soil under the galled brackets and managed to rear adults of this interesting fly.  When newly emerged they were bright orange as in the photos, but as they matured they changed to orange brown.

A. wankowiczii is a species that seems to have arrived in the UK in the early 1990s and has been spreading north from Kent.  The pimple galls are very distinctive and easy to recognise and I'm keen to hear from anybody who has seen them in order to get an idea of the distribution of the fly.

If you think you have found them just take a photograph of the bracket fungus and post in this forum.
good hunting!
Judy

Last edited by Judy Webb (2009-09-22 01:40:59)

Thanks, Scotty. Very interesting.
Judy

Further to my message of 17th August I have re photographed the thistle galls at the same location.

It appears that the flies have emerged and presumably will either mate and lay more eggs, or will be over-wintering as adults.

Have you looked for grubs? Or mites? There is a Dasineura sp. (aparines?) which causes similar on Galium aparine. Try Keith Harris at BPGS - a Cecidomyiidae expert.
Regards
Scotty

I collected some creeping thistle galls last month and kept them just dry on my desk as before.  Two days ago insects started emerging.  First two female Urophora cardui and yesterday 2 small parasitic wasps as well!  I wonder how the soft teneral flies could bore their way out of the hard dry woody galls - any ideas?

if anyone knows where these galls are and collects some now, you could do just as well as I.  The parasitic wasps will go into alcohol for expert attention at the Natural History Museum.  The adult flies sitting in natural position display the most amazingly striking wing pattern - with the wings closed the pattern resembles pincers of a scorpion to me.

If you want to convince a non believer that flies are not boring, this is a species that will open their eyes!

Judy

Hello every one,

I recommend this book "British plant galls" Margaret Redfern and Peter Shirley
ISBN 1 85153 214 5.

Best wishes

PIERRE MILLE wrote:

Hello every one,
I recommend this book "British plant galls" Margaret Redfern and Peter Shirley
ISBN 1 85153 214 5.
Best wishes

This excellent book (published by the Field Studies Council) is the product of work by members of the British Plant Gall society.
http://www.british-galls.org.uk/
A revised edition is in preparation; I understand that the separation between fungi-caused and other gals, that I find confusing, is to be removed. Various updates, including taxonomic changes, can be downloaded from their web site-
http://www.british-galls.org.uk/british … insert.doc 

Judy Webb wrote:

I collected some creeping thistle galls last month and kept them just dry on my desk as before.  Two days ago insects started emerging.  First two female Urophora cardui and yesterday 2 small parasitic wasps as well!  I wonder how the soft teneral flies could bore their way out of the hard dry woody galls - any ideas?
Judy

On the British Plant Gall society Yahoo group ( http://uk.groups.yahoo.com/group/british_galls/ ) there is a posting by Margaret Redfern which includes this topic for Urophora cardui (and other related information) -
http://uk.groups.yahoo.com/group/britis … essage/851
"Urophora cardui larvae cause chambers that are not sealed over - a tunnel to the surface remains, usually stuffed with chewed up debris. In order for the fly to emerge successfully as an adult, the gall has to fall to the ground (usually in the autumn) and rot a bit so that the fly is able to push its way out. So, the gall tends to fall apart. If the gall remains on the plant above the ground this often means it doesn't rot and so the larva doesn't pupate or emerge."

A couple of other leafmine sites that may be of interest-
http://www.ukflymines.co.uk/   leaf and stem mines of flies of Britain (and other orders).
http://www.bladmineerders.nl/   Leaf miners of Europe (bilingual) includes Galls