Return to HRS home page Dipterists Forum
A Dipterists Forum recording scheme

Navigation
Home
Forum
Photo gallery
Maps
Checklist
Hoverfly Newsletter
Memberlist
User-groups
FAQ
Search

User
Username:

Password:

 Remember me



I forgot my password

Don't have an account yet?
You can register for FREE


Search

Advanced Search

Who is Online

In total there are 5 users online :: 0 Registered, 0 Hidden and 5 Guests

Registered Users: None

[ View complete list ]


Most users ever online was 248 on Wed Dec 12, 2007 11:53 pm


Brachyopa weekend
Goto page Previous  1, 2
 
Post new topic   Reply to topic    Hoverfly Recording Scheme Forum Index -> General discussion
View previous topic :: View next topic  
Author Message
conopid



Joined: 03 Sep 2005
Posts: 342
Location: Shrewsbury, Shropshire

PostPosted: Wed May 14, 2008 8:13 pm    Post subject: Reply with quote

Hi Roger,
6,000 pins per annum! Blimey. I am a mere novice by comparison. I probably use 1,000 - 1,500 and that keeps me very busy. Where do you find the time? However I have recently developed a worrying tendency to collect from more and more families and find myself collecting more and more specimens, I've recently strayed into Empids, Dolis, Tachinids, etc. etc., so maybe one day I will suffer from overload as much as you do. Very Happy

A bit off off topic, but tonight I swept loads of Lonchaeidae from riverside trees. I don't think I have ever noticed so many before. Have brought about twenty home - another family and more pins! Have you ever come across large numbers of this family? (I should really post this bit to the Dipterists' Forum).

_________________
Nigel Jones
Shrewsbury
Shropshire
Back to top
View user's profile Send private message
Roger K.A. Morris



Joined: 06 Nov 2005
Posts: 1583

PostPosted: Wed May 14, 2008 9:06 pm    Post subject: Reply with quote

Hi Nigel

You've just hit the normal problem - how to deal with large amounts of material!

I've never experienced what you have described - maybe worth dropping Iain Mc Gowan a line.

I don't cope - I'vce still got 1500 specimens to deal with - mainly hymenoptera and non-syrphid flies plus a few hundred beetles. I hold on to material from as many recording schemes as I can - my aim being to make sure a weekend away adds something to every scheme.

Regards

Roger
Back to top
View user's profile Send private message
chris webster



Joined: 19 Jan 2006
Posts: 12
Location: Reading Berks

PostPosted: Wed May 14, 2008 10:04 pm    Post subject: Reply with quote

OK.. you win. I quit.
First point: I'm not an entomologist. Watching and photographing hoverflies is just one of my many hobbies. But I post something I think is interesting, about how the thickness of hind femora of Brachyopa might be an aid to identification, and also that a male was observed keeping station above a sap run even though that was on the shaded side of the tree... and I just get rebuked for not killing the thing.
"misplaced concern that specimen-taking will damage populations of rare species"... Well, how do you estimate the population size, so you know if you'll damage it? As I said, I found one good sap run in that wood, and that tree was the focus of activity... 2 Criorhina species and a Brachyopa male. In the course of an hour, I saw only that one male, confirmed by photos. Estimate the population size.
In the course of looking round another Reading wood yesterday, I saw a single Melangyna cincta. I'd seen just one in that wood before, 5 metres away, in 2007. Also a single Dasysyrphus venustus, 20 metres from where one was seen in 2007. One Epistrophe melanostoma in 2007, exactly where one was seen the previous year. You may say there are plenty there, so I can kill a few. But it looks like I'm seeing them in what they find to be the optimal sites, so where are the rest of these supposed populations?
I was just starting to identify hoverflies in 2004, and have a few records of Dasysyrphus tricinctus that year near Reading. I've seen none since, though I'm better at spotting such things. Estimate the population size.
Same goes for Leucozona laternaria, not seen since 2005. Logically, populations that fall to zero were approaching zero the previous year. QED.
Because we know where to look for various species, and find them there, we may forget the intervening arid spaces where they don't exist, and thus be over-confident about population sizes.
Anyway, as I said, I quit. I'm clearly not a proper Hoverfly Recorder. So here is my parting gift: the URL of my galleries of hoverfly photos, defiantly identified without the use of a microscope!!
http://syrphidae.3644.co.uk/
count to ten... no, best not to look!

Chris.
Back to top
View user's profile Send private message Visit poster's website
conopid



Joined: 03 Sep 2005
Posts: 342
Location: Shrewsbury, Shropshire

PostPosted: Thu May 15, 2008 7:41 am    Post subject: Reply with quote

My comment wasn't aimed at you personally Chris. I was commenting on an attitude I come across frequently.

Over the years, I have thought long and hard about collecting and I am convinced that taking one or two specimens will not damage populations of scarce invertebrates. In situations where a species is down to just a few specimens, in a wood say, it's probably doomed anyway as such small populations are very unlikely to survive. However, I do not believe that we can encounter the only fly of a particular species in a particular location. It would literally be like finding a needle in a haystack. Where we know a species is genuinely rare the vast majority of entomologists would not take a specimen, if it could safely be identified in the field. However there are very few very rare hoverflies in the UK. The compelling need is to find undiscovered populations of such flies in order to protect/manage those sites.

If hoverfly collecting was a popular pass-time, with many practitioners, which it is definitely not, then we might be looking at a different scenario. But for now I think you can rest assured that you can collect critical specimens and I really would urge you to do so to help build our understanding of species in the UK.

_________________
Nigel Jones
Shrewsbury
Shropshire
Back to top
View user's profile Send private message
Roger K.A. Morris



Joined: 06 Nov 2005
Posts: 1583

PostPosted: Thu May 15, 2008 8:52 pm    Post subject: Reply with quote

Hello Chris

I think we may have given you a rough time - sorry. Several key points that may help:

1. You have some excellent photos and many provide possible records which are very useful.

2. Your concern about impacts on populations is genuinely unfounded - Stuart and I did a mark-release-recapture study of Volucella inflata a couple of years ago at a site where it occurred in small numbers - using this technique we were absolutely astounded by the numbers we marked - over 200 and the estimate of population we got was well in excess of 600 individuals (for V. pellucens the estimate was in excess of 2,000 equalling the product of 60+ wasps nests - yet we only knew of one in the whole half mile ride.

3. You have the potential to make some massive contributions given that you do seem to manage to find interesting material - relatively few people do! The problem is that there comes a point where one genuinely does need to provide corroboration in the form of specimens - we are getting to a possible crisis as we are seeng a very serious decline in the recording of tricky taxa and that is skewing data badly - if anything that has more worrying implications for conservation because we will just not be able to follow what is going on.

4. Having spent years looking at hovers, I still find that I make mistakes and have to go back to specimens. Also I det material that flummoxes me - I spent an hour this morning puzzling over a couple of Cheilosia that just don't look right for where they seem to come out in the key - so I will have to get them checked.

Rather than give up, why not join what is a relatively small band of specialists and make the sort of contribution that conservation needs. Believe me we are sufficiently worried about recruitment that Stuart and I spend at least 4 or 5 weekends each year running courses -often at our own expense (we are not paid to do this). If the situation was rosy we would not be doing this and thinking about making funding bids to buy microscopes to run courses - and the time commitments are not small either in conjunction with very busy jobs weekdays.

Hope this reaches you and that you have not logged off for good

Regards

Roger
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Hoverfly Recording Scheme Forum Index -> General discussion All times are GMT
Goto page Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum


Powered by phpBB © 2001, 2005 phpBB Group