Diptera.info

Posted by nick upton on 28-09-2018 19:39

I hope someone can confirm my ID for this fly which was new to be and is a nationally scarce species in the UK.

c 20mm, flying around and standing on recently felled trees (not sure of species) in damp woodland in Gloucestershire, UK on 27.9.18

As far as I'm aware there are only two Gnophomyia species in the UK, G. elsneri which looks quite different and has a very limited distribution, not near my site, and my photos match images and habitat descriptions perfectly for G.viridipennis (whose grubs feed gregariously under the bark of recently fallen trees, usually Populus spp.

Edited by nick upton on 30-09-2018 22:27

Posted by nick upton on 28-09-2018 19:41

A profile view of an individual with a damaged left wing. NB of 4 flies I photogrpahed, 3 were damaged, as two others had missing legs. They must be as fragile as they look...

Posted by nick upton on 16-10-2018 18:11

Any expert comment on this post would be most welcome as the woodland reserve where I photographed what i think is a rare fly in the UK is keen to know if I am correct. The logs these flies were on may well be carted away soon, unless I can offer expert confirmation of my find! I suspect there may be many more elsewhere in the wood, unnoticed, but I can help ensure this home survives if the ID is certain.

Posted by nick upton on 01-11-2018 17:10

I've had some email feedback from Limoniid expert Dmitry Gavryushin from Moscow who says: I could only confirm that the fly looks more like viridipennis, please check my field observations of both G. viridipennis and G. acheron on the same fallen aspen tree in June, 2010: https://diptera.info/forum/viewthread.php?forum_id=5&thread_id=30791

Thanks to this, I am even more sure that my fly is Gnophomyia viridipennis as the halteres are more yellow than in the G.acheron images Dmitry posted and G.acheron is also not recorded from the UK.

We have scarce records of G. viridipennis here (with G. lugubris sometimes given as a synonym) and even fewer of G. elsneri (which looks quite different) from just one confirmed location near London. G. acheron seems to be an Eastern European species, so unless it has been missed in the UK, is unlikely to be a possible ID, and I think G. viridipennis remains a very likely ID for my fly, though further corroboration or comment from experts would of course be welcome.