Is this volucella imanis? (link to image added)

[SteveRoberts]

We're not hoverfly experts, but my son spotted the attached at Anderton country park (SJ657750) this afternoon (25/7).

http://personalpages.manchester.ac.uk/staff/Steve.Roberts/hoverfly-compressed.jpg

Our limited books would suggest volucella inanis, but your distribution maps suggest it hasn't been recorded in Cheshire? But moving north?

Sorry not a very good photo - it flew off before I could get anything better. The flowers are raggwort for scale.

Confirmation of ID would be nice - if we are right then we can submit it as a record?

Thanks

Steve

[seems I can't add an attachment! 19kb JPG) - error message "Sorry, but the maximum filesize for all Attachments is reached..." so added a link]

[Geoff F]

Take this reply with a large pinch of salt, until a real expert appears.

Your specimen certainly has the typical Volucellini outer cross wing vein, and the only other species which I could consider is V. zonaria which is even more of a southern species.

The wings of your specimen appear, to me, to be a touch on the orange side although that is probably a trick of the light and the black abdomen areas are a bit on the broad side.

But I still can't easily get it to fit with V. zonaria so it appears that your suggestion is the most likely.

Wait for another more experienced opinion though.

[benacre]

Hmm I am aware of the species in Suffolk but depends on recorder activity as to the maps, so I would say the first id is right but I am only a dabbler in Diptera so who am I to say.
LOL

[Roger K.A. Morris]

Hello

This is a tricky photo but my gut feeling tends towards V. inanis rather than V. zonaria (although I find myself agreeing with Geoff's analysis in many ways).

From a recording perspective, I think this can be safely listed as V. inanis because:

1. The thorax appears to be dark, not chestnut
2. The second tergites appear to be yellow not chestnut
3. The wing colours look closer to V. inanis than V. zonaria.

On the point about recording, both V. inanis and V. zonaria are really quite well recorded because they are obvious and generally ID able from photos. Both have been recorded to the latitude of this record.

Regards

Roger

[brianh]

I didn't comment earlier because until a few days ago I didn't have both of the species before me to compare. This picture shows the difficulty of identification from photographs when not all diagnostic characters can be seen. I do not disagree with any of the comments made earlier, but add my observations.

With the two species to hand then the difference in size is apparent and can be measured - in Stubbs and Falk the stated wing lengths do not overlap in the two species. Also it is possible to look at sternite 2 which is yellow in V. inanis and black in V. zonaria. Side by side, in V. zonaria the thorax is shining rather than the relatively matt V. inanis, and the relative difference in the width of the black bands on tergite 3 can be compared (both of these are probably quite variable). In my specimens the small dark patch near the wing tip is slightly more obvious in V. inanis, but this is quite subtle.

This emphasises that it is often very difficult to make identifications from photographs, however good the photograph is. Roger does very well to identify as many as he does from photographs, but this is based on years of experience. Fortunately I was able to make my identifications on the basis of wing length and sternite colour.

[Roger K.A. Morris]

mmmmmmm

I'm starting to doubt my ID

Don't put a name to this one - I now suspect V. zonaria - Brian's point about shiny thorax a valid one. This is a bit of a failing on my part - so just shows the problems with photos.

In terms of distribution - V. zonaria appears strangely enough to be moving a wee bit further north than V. inanis

Regards

Roger

[SteveRoberts]

Been on holiday. Thanks for all the comments - seems we were right in the two we narrowed it down to V. inanis or V. zonaria. The size made us think of V.zonaria whilst the abdominal markings looked much more like the drawings we could find of V.inanis. It was the dramatic size that led us to notice it. We went for the colour/markings as we didn't get chance to measure the size and can only definitively say "bigger than a ragwort flower"! I think I gather from the discussion that the markings are not that reliable a guide? Looking at the photos on this excellent site I would probably have plumped for V.zonaria on the basis of the broader abdominal markings - our books had the zonaria much paler. But the thorax does look quite dark.

Am I right that size is a better guide here? I am better on things like butterflies where size can be quite variable.

I've put together the three pictures I have - slightly different angles, but poor focus I'm afraid:

http://personalpages.manchester.ac.uk/staff/Steve.Roberts/hoverfly.pdf

As I work opposite Manchester Museum I might pop over and see if I can look at their specimens - might be cleaer if I can see both (albeit preserved)

Thanks

Steve

[Jason Green]

I think I'll go for zonaria too.

Shame it wasn't female. I had both these species (girls too) side-by-side the other day for another comparison, and without any magnification the first thing that struck me was the width between the eyes. You can fit three ocelli between the eyes of a female inanis, and as many as five between a female zonaria'. Still, I don't have S&F yet, so it's probably known.

[SteveRoberts]

Just been over to Manchester Museum. They have a very impressive collection. Looking at the two side by side both me and the resident helpful entomologist were agreed we had V.zonaria.

This has been a facinating introduction to the world of Diptera - thanks

Steve

[Roger K.A. Morris]

Hello

Size is not a great indicator as V. zonaria is a bit variable.

I've been musing and am now convinced of V. zonaria

Regards

Roger