How are Lacewings Identified?

Yashca · #1 (**permalink**) 21-12-2010, 03:31 PM

I found a lacewing in a spider's web today, and have been looking at it under my new microscope. I wondered how it was that Lacewing species were identified - is it the veining on the wings or some other anatomical feature? And, if so, would I be able to spot it under the microscope and identify it to species level?

I do have the ability to take pictures through the microscope, but they are not of the very best quality.

Jason Green · #2 (**permalink**) 21-12-2010, 03:59 PM

Afternoon Yashca,

Well, first you'll need Colin Plants key to the group - Lacewings and their Allies. Try Pemberley Books, the NHBS, Amazon, etc. It'll set you back by only £7 or so. The book also includes a key to Scorpionflies and I believe another group.

What microscope do you have? I use a 20x stereo model. The wings are very important - both venation and the angle the hairs stand at that grow from the inside of the forewing veins. The presence of black markings on the top of the thorax area is important too, that can be subtle. Various facial views are needed too. I haven't got the book - hoping to get it soon! My thanks to Geoff F for his summary of key identification areas recently.

Good luck with the process, let us know how you get on. Records of these 'specimen species' are often under-recorded, so please pass the record onto your local recording centre - ask your nearest Wildlife Trust who that is.

Take care,

Jason

Yashca · #3 (**permalink**) 21-12-2010, 06:26 PM

That is fantastically thorough Jason, thank you. I will have to get in touch with the relevent people for my area, and that book will probably be the first thing I buy in the new year.

As for my microscope, I'm not sure exactly about the magnifications and so on, it is a very old third hand one, but I have mounted a webcam at the top so I can take pictures through it, and they come out surprisingly well considering.

Jason Green · #4 (**permalink**) 21-12-2010, 06:52 PM

I assume this is a stereo dissecting model? The eyepieces should help with confirming your magnification; the eyepieces should say WF10X or WF20X or similar (I think some may need more searching- it could be around the apperture, or base you insert into the eyepiece-tube).

The magnification is based on the objective lens, perhaps 2, 4 or 6x. You then multiply this by the number on the eyepiece. For example, my model has a 2x objective with WF10X eyepieces - 2x10 = 20x magnification. WF is short for 'Wide-field'.

If you can't see any numbers for the eyepieces or objectives, put a ruler milimetre-side forwards and take a photo of the increments through the lens. Post the photo and we'll try and help decide your magnification

The best of luck to you - just enjoy what will hopefully be a pleasurable experience, your first microscopial identification of a group that need attention

Yashca · #5 (**permalink**) 21-12-2010, 11:21 PM

Right, I've had a good look at the microscope, and a good read of your post, and I think I understand what's going on now.

My microscope has two interchangable eyepieces, x6 and x10. It also has four lenses that can be rotated above the specimen, these are x3, x10, x40 and x100.

So my possible magnifications are:

x18 (minimum magnification)

x30

x60

x100

x240

x400

x600

x1000 (maximum magnification)

When playing around with it over the last few days I've only used the first few magnifications, the others are far too large for insects (but may be good for algea or something?)

The image quality is pretty good, but the lighting of the specimen is the thing causing most trouble. As the microscope isn't really designed for the purpose I'm imposing on it, I'm having to be creative, so when looking at the face of a spider, I turn off the light illuminating it from below, and shine a torch through a piece of translucent white plastic to act as a diffuser. Very crude, I know, but the whole set up cost very little. I'd love to get a proper microscope designed for the purpose with built in camera and so on, but I can't afford it.

It works well enough, at least, for me to be able to count at the hairs on a garden spiders leg, and see the eyes quite clearly. Hopefully this will will good enough for me to do at least some microscopic identification.

Jason Green · #6 (**permalink**) 22-12-2010, 12:17 AM

I think you have a 'Compound microscope' there - the thing used to view slides at high magnification. It could be useful to view the wings though at 30x, though!

You need a 'Dissecting/stereo-microscope' for these identifications, typically 20-40x magnification. There is a lot of rotating and manipulation involved, and for that you need space between the specimen plate and objective lens.

You can get basic models with WF10X eyepieces for around £50-60 or so, they seem to be widespread enough at the moment. More expensive versions can take additional objectives for more magnification and have the eyepieces set at 45' angles for a more comfortable viewing angle. I'm hoping to upgrade later next year.

Feel free to ask for our views on a model if you see one!

Yashca · #7 (**permalink**) 22-12-2010, 10:45 AM

Is it possible, Jason, for you to post a link to a website that sells such microscopes?

Recently, the idea of tring to identify all the tiny little things that usually escape my notice has been at the forefront of my mind. For Christmas there is the possibility of some guides, land snails, caddis flies, caddisfly larvae, and possibly a few others. I'm also working on the construction of a beating tray.

If a proper dissecting microscope would increase my chances of identification of these other little critters, then i feel i should get one as soon as I can afford it.

Jason Green · #8 (**permalink**) 22-12-2010, 11:56 AM

PM'd.

Geoff F · #9 (**permalink**) 22-12-2010, 07:52 PM

It may be the same outlet, but I have had this bookmarked for some time GX Optical Magnifiers Home thinking that I may have to get something next year.

Jason Green · #10 (**permalink**) 01-01-2011, 07:35 PM

Hi Yashca,

My key arrived a couple of days ago. Having had a couple of other groups to do I've only just got round to trying it out. Anyway, all three specimens were Chrysoperla lucasina, part of the Chrysoperla carnea agg.

The specimens show varying size and intensity of markings, so I thought I had more than one species. The important points that were however consistent across the board was the cell IMC's apex not exceeding the R-M cross-vein, the wing-tip being subtley pointed and the head green/pale between antennal bases.

I may still re-key later on just to be sure, but the process 'felt' right.

I'll be interested in your results.