Is this Chrysotoxum cautum or elegans

[Geoff F]

Not really a great deal more to add, Roger. Late July, about half a mile inland from Bolt Head, S. Devon. On a sheltered hedge at East Soar Farm to be precise. Just managed 3 photos before it flew off; and despite regularly visiting the same area I haven't seen it, or a close friend/relative, again.

With regard to what is or isn't worth recording. This year, for example, I saw, and photographed, Xanthogramma pedissequum which was my one and only ever sighting; but I don't think it would be generally regarded as being sufficiently interesting to be officially recorded.

I do try to regularly 'work' the same areas at least once a week during the 'busy season' and make a photographic record of anything which I consider to be of interest. When visiting a new site I tend to record everything including the common species, but only on my personal records; then to save space, I just look for extra species on return trips.

[charlieb]

Originally Posted by Geoff F

Trying to decide what is or isn't worth recording from my various insect sightings is still a bit of guesswork and although I have sent details of a few various species I have omitted most of what I regard as probable common species.

Everything is worth recording, common and rare species - if in doubt who to send records to, send them to your local records centre: Devon Biodiversity Records Centre

[lync]

Originally Posted by JRsbugs

Hi Roger,

I had Chrysotoxum festivum last year and there's none on the map for my area near Lincoln. I had it verified by experts on diptera.info.

Diptera.info - Discussion Forum: Chrysotoxum festivum?

This would suggest the maps are not a totally accurate indicator as some just haven't been noticed.

Janet

But festivum is known to occur at least as north as Yorks and therefore virtually assured in Lincs. That's a completely different from the case of verralli that's never been found in the south-west as far as I'm aware.

[Roger Morris]

Hello everyone

Thanks for your many responses. I'll try to respond to the various points but in no particular order. Please forgive the numbering - it is just my way of structuring the response - not a lecture!

1. The recording scheme is of course only as good as the data it receives. I do travel the country to fill in unrecorded squares but as there are 2,800 or so 10k squares and one of me it is a tall order. However, I do concentrate on the poorest recorded areas (e.g. The Wash, Southern Uplands of Scotland, Radnorshire, the north Pennines. Jolly hard work and a bit frustrating at times but the maps do benefit. As to Lincolnshire - well we actually have very few recorders so I would not be surprised about new records. BUT the key point on C. festivum is that we have suspicions that it is expanding its range. This Lincolnshire record is therefore really quite important and it would be very useful to the scheme (data we need are date, locality grid ref, recorder).

2. As Devon BRC commented, all records are important. Actually one of the problems we have is that people say - "it was too common to be worth submitting". Yet of course we also get people saying "you are missing x or y in that square - I see it regularly in that area". So, there is a point about interaction with all sorts of recorders. However, there is a wider point about records that I'll cover in point 3.

3. The recording scheme started ovver 40 years ago as a mapping project, but it has moved on. The front face of the scheme is the atlas, but amongst the other outputs that we regularly report in the newsletter, at Dipterists Forum AGM, in various society journals and at conferences is the analysis of the data to consider issues such as species richness, climate change and status reviews. We used the data to explore trends prior to preparing the revision of conservation status of hoverflies that we did in 2006. Unfortunatley it has sat with JNCC since then but when it comes out it will be posted on the website. Frequent records of common species are therefore just as important as the odd rarity - in fact they may actually be of more importance in terms of scientific analysis because one needs a big dataset to make valid judgements.

4. I regularly trawl websites looking for data for the scheme. There are problems with photographic data because only a relatively small proportion of hovers can be done from photos - as the debate about C. elegans shows. However, I think it is illustrative of the importance I place on these sorts of records that I regularly spend whole weekends trawling sites. At the moment I'm working my way through Flickr. The biggest problem I find is that relatively few photos have data attached and often it is not possible to contact the photographer. I pretty well gave up looking at Wild About Britain for this reason and would like to encourage contributors to add data. Sadly some very useful records have eluded me as a result.

So, what does this add up to? Well, I would encourage photographers to keep data on where, when photos were taken. Those of the commonest species may actually be really important for useful studies. For example, Epistrophe eligans is a really useful climate change indicator that could be recorded by a network of local recorders across the country - e.g. contributors to Wild About Britain. I would dearly love to set up such a network of recorders do this sort of thing. On a similar note I want to set up a garden hoverfly recording initiative. It won't be 100% accurate but could be developed to be the same sort of indicator as the RSPBs garden bird survey.

My direct contact details are roger.morris@dsl.pipex.com.

I hope this diatribe is not too boring.

Regards to all

Roger

[ChrisR]

Wise words Roger - good to see you on WAB

I agree with everything you have said, regarding records - when we (putting my Tachinid Recording Scheme hat on) say 'all are welcome' we really mean it ... Tachina fera, Eriothrix rufomaculata - common as muck but they must be in more squares than we have dots for them so we must still be data-deficient. The minimum we need in terms of data is:

• Grid Reference (O/S Landranger or Lat/Long style - even a post-code is better than nothing and can be converted usually)
• Date of sighting
• Recorder's name

... though we won't complain if you also include:

• Location name
• Habitat
• any host/rearing information, if you have it
• etc.

I remember chatting with a reptile & amphibian recorder a while ago and he made a very valid point that now we worry about the decline in reptiles & amphibians across the country but when he looked back in old journals he had real trouble finding records for frogs and grass snakes because back then people considered them too common to bother recording. It was only when people thought they were declining that they started to do really serious recording and by that time it was too late!

[JRsbugs]

Roger,

It's a good job I thought to check it on the map! Another first I have for Lincolnshire then as well as a few rarities... I must check all my other Syrphids too now. I'll get my grid details sorted then send it to you. Your searching here did not end in vain

Chris, I have some more Tachinids I need to ID too so should get onto that soon, the weather needs to change for the worse to give me more time.

Janet

[JRsbugs]

Roger, I think you will definitely be interested in this one! Last year, 24th June 08. I have sent you the location etc. for C. festivum, same details.

Eupeodes lapponicus

Diptera.info - Discussion Forum: Eupeodes lapponicus?

I have

Janet

[JRsbugs]

Another a bit sparse on the ground...Meligramma triangulifera on 13th July 2008.

Diptera.info - Discussion Forum: Meligramma triangulifera?

I hope you don't mind me posting these here Geoff, but now started they will get the attention they require.

[Jason Green]

Interesting records, Janet. So, E. lapponicus... what's the distinguishing feature to look for here? To my obviously quite ignorant eyes I can't tell a great deal to seperate it from E. luniger. Leg colour or something?

What a great record I'm sure it is, from Hoverfly.org.uk:

A very rare species with old records from the Scottish Highlands, but with the very few recent records from south-west England. It is considered to be a highly migratory species in continental Europe

Oh, and welcome to WAB, Roger

[eucera]

Hi Roger

It certainly IS good to see you on here!

wrt to using a site like WAB for data gathering and asking for full data with each pic: I raised this very question in a thread a couple of years ago and had a rather mixed response (I think you might be able to see the immense traffic it generated if you search for my posts).

I do hope that the debate can move on a bit and that people will realise just what a fantastic resource this site is AND, especially, how the data can have a wider use beyond just putting a name to a photograph. I remember reading comments you made a few years back IN BW magazine about photorecording - and some of the problems associated with a move towards relying on pics to generate data (eg some common species that are inseparable from other common species using pics only can appear to be in decline as the number of validated records decreases - if I remember an example correctly).

I hope that your very thorough and helpful postings will meet with a positive response.

Cheers, Stuart Roberts
BWARS Home Page