Is this Chrysotoxum cautum or elegans

[Roger Morris]

Hello everyone

I'm afraid I would not accept this record as E. lapponicus. I really don't see how this can be identified from a photo - Jason, to my mind you are right and my immediate reaction was E. luniger.

The critical feature is a dip in the wings that separates Lapposyrphus from Eupeodes which is not apparent from the beating wings. Sorry, but I'm going to have to discount this one.

Regards

Roger

[JRsbugs]

Originally Posted by Roger Morris

Hello everyone

I'm afraid I would not accept this record as E. lapponicus. I really don't see how this can be identified from a photo - Jason, to my mind you are right and my immediate reaction was E. luniger.

The critical feature is a dip in the wings that separates Lapposyrphus from Eupeodes which is not apparent from the beating wings. Sorry, but I'm going to have to discount this one.

Regards

Roger

Fair enough, the person who confirmed it usually doesn't make mistakes, nor does he confirm IDs if he is at all uncertain but on this occasion maybe he made a mistake. He is the 'resident' Syrphidae expert but is in Europe. I had no idea at the time how rare it was either, I simply found one which it looked like.

[JRsbugs]

This went twice when I edited!

[JRsbugs]

Maybe it's a good idea to start another thread for identifying any Syrphids. Now that you are here Roger you can identify them are for us!

I have yet to name some so when I get them better sorted I will post them for ID or confirmation.

[Jason Green]

Originally Posted by JRsbugs

Fair enough, the person who confirmed it usually doesn't make mistakes, nor does he confirm IDs if he is at all uncertain but on this occasion maybe he made a mistake. He is the 'resident' Syrphidae expert. I had no idea at the time how rare it was either, I simply found one which it looked like.

I'm sure luniger is very much needed as a record though, especially as it's common and so maybe not recorded as much...

Maybe in some parts of Europe it's the predominant species, but over-looked the fact it was seen in the UK - and so thought it most likely? Not sure...

[ChrisR]

Originally Posted by JRsbugs

Fair enough, the person who confirmed it usually doesn't make mistakes, nor does he confirm IDs if he is at all uncertain but on this occasion maybe he made a mistake.

Perhaps revive the thread of DI and ask Andre politely why he was so sure about the ID and why he discounted luniger? I am sure he'd be happy to clarify his ID and we can judge whether it was an off-day for him

[Roger Morris]

Hello everyone

In terms of and ID thread, my recommendation would be to sign up to the Hoverfly Recording Scheme website Hoverfly Recording Scheme - Index - I've always dealt with records there and there are several others who regularly trawl the site and provide advice. The shot can then be posted on Wild About Britain with more confidence. However, I will keep an eye on records and give opinions from time-to-time.

Going back to the general principles of ID from photos, I'm afraid I hold quite a bit of sceptocism about ID from photos. At a personal level I quite frequently find myself saying "I am just not sure because I want to see x or y". Maybe I'm just not sufficiently competent but I generally avoid doing field identifications on many of the difficult genera. In the case of Eupeodes for example, it is a bit of a nightmare genus with small characters that are not revealed in photos e.g. microtrichia on the wings. I know some people exude great confidence about ID of photos, and I confess I would err towards the same ID. But, I'm afraid I have also found that I've been wrong - so I don't put a name to anything that might be confused with something else.

Stuart Ball and I have developed a classification of ease of identification which shows just how tricky we and other specialists regard hoverflies. In tyhe Case of E. lapponicus I think we would expect to see a specimen because it is just too tricky.

Regards

Roger

[ChrisR]

I agree with Roger ... with the tachinids we have often discussed how many field-identifiable tachs there are in the UK and it always comes down to a very small % of the 270-odd species you could possibly find here.

One of the main issues is that most photographers are happy to accept a name with a much lower degree of certainty than, for instance, a recording scheme would. Looking at a photo you can always say what the fly *looks* like ... but seldom can you actually say what it *is* because the characters that really define the species are usually so small.

A classic example of this is the very common species Phania funesta, which is very easy to ID from photos ... except that it can only be split from its very rare cousin P.thoracica by examining a specimen under a microscope. If we take loads of photo-records then we would be meerly guessing (even if we were correct 99% of the time) and it would artificially bias the recordset towards the common species and we wouldn't notice a potential increase in the population of P.thoracica.

Also, recently Dipterists like Ivan Perry have discovered quite a few new species by closely examining specimens that would otherwise have been given the name of an existing UK species because they look very similar. Only when you run a lot of material through European keys do you come up with these newcomers - or in the case of Linnaemya picta, find that a well-known colony has been misidentified for decades.

[Jason Green]

Originally Posted by ChrisR

Perhaps revive the thread of DI and ask Andre politely why he was so sure about the ID and why he discounted luniger? I am sure he'd be happy to clarify his ID and we can judge whether it was an off-day for him

I'd like to know too - surely luniger would jump out strongly??

[JRsbugs]

I'm not sure what the best line of approach here is. I had thought of privately mailing Andre to ask what his ID criteria was, he may have had an off day but then again not. I'm no expert, I just go on what I see and what I have learned but I try not to push what I see without the vital evidence. Take for example one I had identified recently on which the vital feature could be seen, that is short setulae on the inside of the foreleg femora of a Lauxaniidae Meiosimyza rorida. Two worldwide experts egreed without doubt because this feature was visible, and I have found that no-one on this site will identify anything without being able to see something which excludes other species.

Diptera.info - Discussion Forum: Lauxaniidae Meiosimyza rorida?

Yes, on the odd occasion someone has an off day as we all do. I may have to bring up the thread 'gently' in order to see what is said as Chris has suggested.

One point about taking IDs from pics, I must say that in a good number of cases a fly would not have been caught, or in my case I don't want to catch them. This surely gives rise to many valid records which otherwise would have been missed. With the improvement of digital camers, combined with an individual's passion and desire to take photos, this has to be a bonus to any recording scheme.

I went to the trouble earlier this year to sell a lot of items I had and did not want on ebay to raise the money to buy a good macro lens and a teleconverter, and believe me I had more hassle than anyone would want in a lifetime with a subtle but vicious fraud attempt, apart from the usual problematic people.

My interest is first in getting good pics, but I wanted to get those smaller flies more than anything in good detail hence the move to macro and manual photography which to anyone who has not used a DSLR before was a huge leap. Of course then getting to know what I have is great, and helping recorders to know what there is here is the icing on the cake I would say.

I have thought about the best approach of getting my flies either identified (or confirmed for the easier ones). My thoughts for the Syrphids were to start a thread here in order that a good number of other people may be able to view them and perhaps also be encouraged to take a closer look at what they have in their areas. This could have a rollercoast effect as I'm sure there are many people who would like to do this but feel a little discouraged because of the enormity of it all. I would like to say to those people, do it and see, I started not many years ago and knew nothing.

In the past I have taken my uncertain flies to Diptera.info, I feel relatively at home there and now I can take better pics I have a far better chance of getting IDs. I have at the moment around 700 pics in my Syrphid fly folder from spring this year , of course not all different species! This is going to take me some time, apart from these I have probably got close on 3,000 pics of other flies in the same period! Then there's the bees, beetle etc... yes I take everything that moves!

Let me stew on it a while....

"I'd like to know too - surely luniger would jump out strongly?? "

Jason, yes that is what I thought about E. luniger, I must admit it had not even entered my head that it could be that. And E. luniger is one which I have been familiar with from the outset. But at the same time I admit to not being an expert and understand the problems which can arise.