Sawfly (maybe) to identify please

[Gateside]

I took 3 photos of a flying insect on 23rd August, but have just got round to trying for an ID.

It was small (8 mm long?) weakly flying, non-waisted, orange abdomen, black thorax, and robust antennae, with interesting variations in the length of each segment.

No view of the tail tip to see if it's pointed.

Desciptions with each photo.

I have got as far as it probaly being a sawfly, but none of my ref book illustrations seems to match.

[Dillybythesea]

Just in case Janet doesn't come by, she kindly put me onto this HYMIS photo database the other day, which might be relevant >

Fotogalerie - Hymenoptera Information System (HymIS)

when I had a similar sawfly, which in my case turned out probably to be Athalia circularis - but had more black on the underside of the thorax.

I shall watch with interest to see what the experts say.

[Dillybythesea]

I shall bump this up in the hope that Someone Who Knows will comment! Otherwise I shall blame myself for intervening!

[JRsbugs]

Tenthredinidae, Athalia glabricollis looks possible. I can't say for sure, there's a few on bold systems which look the same but some others I checked don't appear to be in the UK. This one looks fairly common.

BOLD Systems - Taxonomy Browser glabricollis

Athalia glabricollis Thomson (a sawfly)

You might want to check out other Athalia species..

BRC - Database of Insects and their Food Plants

[JRsbugs]

I tried to post another but the site was down! I had one similar, had to search for it though.

It could be Argidae, Arge ochropus.. but Arge sp. usually have thicker ends to the antennae so that might not be correct.. somehow the antennae don't look like Argidae.

NatureSpot

Now you can see how difficult these are.

[Gateside]

Thanks for all the help on this ID.

I am getting the impression that it might only be taken to family level, but it's further than I could take it.

I am thinking of trying the BWARS forum, to see if anyone there know either way.

[poschiavanus]

Originally Posted by JRsbugs

I tried to post another but the site was down! I had one similar, had to search for it though.

It could be Argidae, Arge ochropus.. but Arge sp. usually have thicker ends to the antennae so that might not be correct.. somehow the antennae don't look like Argidae.

NatureSpot

Now you can see how difficult these are.

It's not Argidae, they have only 3 antennal segments: see the FSC Key to Sawfly genera. The description for Athalia seems to show this is more in the right direction:

44. Tribe Athaliini. Containing only one genus, Athalia, in Britain. Athalia are usually 5-7 mm in length, and have black-marked thoraces and orange abdomens and legs. In most species, the tips of the tibiae and tarsal segments are black giving them a banded "football sock" appearance. A. cordata Lepeletier is one of the commonest British sawflies, and other species are also abundant particularly in damp areas. Athalia species often have 10 or 11 antennal segments. Specific identification can be difficult, and a clear view of the teeth on the female saw may be necessary. Nine species occur in Britain.

There are also two wetland species of Selandria which have orangey-yellow abdomens and a thickened dark costa, but AFAIK they don't have stripey football sock legs.

[JRsbugs]

Originally Posted by JRsbugs

Tenthredinidae, Athalia glabricollis looks possible. I can't say for sure, there's a few on bold systems which look the same but some others I checked don't appear to be in the UK. This one looks fairly common.

BOLD Systems - Taxonomy Browser glabricollis

Athalia glabricollis Thomson (a sawfly)

You might want to check out other Athalia species..

BRC - Database of Insects and their Food Plants

Gateside, this was my first suggestion, Arge sp. was dubious as stated above.

posch, one day I will have to get a copy of the FSC Key to Sawfly genera! I'm not sure I would get much use from it but if it's not expensive it might be worth it.

[poschiavanus]

The FSC Key is quite useful, mainly relies on venation, although one or two couplets use venation of hind wing which I find more or less impossible to do in the field.

There is of course also the Faune de France volume by Berland available as a free PDF download. This is pretty useful as it gives keys to species.

A quick flick through pictures on various internet sources suggests that there are a large number of images labelled Arge which are misidentified, including from sources I would normally regard as reliable.

[JRsbugs]

Thanks posch, I managed to dowload the correct one! I've had trouble with those before, couldn't dowload the vespiformes one but that seems to work now maybe due to a change of server. French is a problem but at least the text can be copied to paste into a translator if needed. The diagrams could be useful. It might be quicker to learn French.