Pedipalp removal procedure/examination for ID purposes

[Jason Green]

Evening all

Out of interest - how exactly is the procedure carried out, when the pedipalp is removed from a male spider to make a reliable identification of a species; is it difficult, and would a 20x stereo-microscope be sufficient?

Take care,

Jason

[frits_b]

I can't say that I have a lot of experience examining pedipalps, but I know that 20x magnification is good for the larger species. For smaller spiders such as most Linyphiids 100x is necessary.

Since I'm thinking of getting myself a microscope, I'm also quite interested other folks' experience.

[No.9 Spider]

It is rare that I would remove the pedipalp for examination under the microscope. With a male specimen on it's back you should be able to examine the pedipalp, though often the pedipalp tends to 'curl up' making examination awkward and you may have to somehow hold it outstretched.
I have the specimen in a watch glass with 70% IMS (Industrial Methylated Spirit) and most importantly 80 micron fine glass beads which are usually adequate to hold the spider in the required position. Remember that all the illustrations in Roberts and Lockett and Millidge are drawn from specimens immersed in spirit and this can make a difference, as well as the position of view being critical. Should you need to remove the pedipalp they are quite easy to detach by holding and pulling with fine tweezers as close to the body as possible.
Magnification wise I use 20x and 40x which are adequate for all but the smallest of Linyphiidae species where 80 or 100x is plenty. A low power stereo microscope is adequate as you don't need high magnification. Most important is a good light source.
Hope this helps.



No.9 Spider

[Jason Green]

It certainly does! Thanks

Originally Posted by No.9 Spider

Remember that all the illustrations in Roberts and Lockett and Millidge are drawn from specimens immersed in spirit and this can make a difference, as well as the position of view being critical.)

So what is this literature, and if it's good where can I obtain a copy - is it OK for a beginner?

[No.9 Spider]

The currently used literature for spider i.d. is Spiders of Britain and Northern Europe (Collins Field Guide) by Michael J. Roberts.
The Collins Field guide contains most British Species aside from all the Linyphiidae. You would have to buy the larger format three volume set to have details for all the Linyphiidae species.
Lockett and Millidge produced an earlier 'spider bible' in the 1950's (British Spiders Vol I and II and a later Vol III with Peter Merrett containing distribution maps) and though it is out of print, copies are available now and again (try Abebooks). I regularly use L & M as a reference when i.d'ing specimens.
As to suitability for beginners there is no choice! and like many species i.d'ing you're in at the deep end from the start but you will quickly gain experience.
You may find 'Keys to the families of British Spiders' by L. M. Jones-Walters (AIDGAP Field Studies Council No. 197) useful in getting to family levels.
Then you'll need glass storage tubes for the specimens etc...., but once you're set up it's an absorbing interest.
You'd also need a licence to buy IMS which is a pain, can be expensive and that's if you can find a chemist that knows what it is in the first place. It's something like 95% alcohol (dilute it to 70% for use as it's ok and your supply lasts longer) same as the purple meths with no colour though. You can buy it cheaply in supermarkets in Portugal, but hey this is the UK .
The licence is free and obtained from your local Customs and Excise as far as I can remember.

No.9 Spider

[Jason Green]

Thanks again, No. 9. I take it the Spiders of Britain and Northern Europe guide has info/plates on palps and/or epigynes?

I'm hoping to get further into entomology this year - collections, etc. I take it to examine the palps you'd need to 'Ethyl acetate' a male first? I realise that may be a silly question...

[ladyhawk]

I had a bad experience when examing a spider under the mirco, it suddenly came back to life and i took of out the door spiders look really big and scary under the microscope thats why i prefer using camera at a distance a long distance got shivers just thinking about it

[No.9 Spider]

Originally Posted by Jason Green

Thanks again, No. 9. I take it the Spiders of Britain and Northern Europe guide has info/plates on palps and/or epigynes?

I'm hoping to get further into entomology this year - collections, etc. I take it to examine the palps you'd need to 'Ethyl acetate' a male first? I realise that may be a silly question...

It has plates of epigynes and palps for all the British species apart from the Linyphiidae where only a portion of them are covered. You can get a 3 volume 'compact edition' (softback, and half the price of the hardback) that contains all the British species. As for ethyl acetate I never found it particularly fast acting on spiders and tend to collect straight into IMS when in the field.
Good luck! I'm on here frequently if you require further advice.


No.9 Spider

[Jason Green]

Thanks Chris. I'll look into that one then, and may call on you when I start

Originally Posted by No.9 Spider

As for ethyl acetate I never found it particularly fast acting on spiders and tend to collect straight into IMS when in the field.

...careful with that, you'll get them intoxicated!

[No.9 Spider]

I usually let them out to pee!


No.9 Spider