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Photo#180757
Bronze Jumper - Expanded palp - Eris militaris - male

Bronze Jumper - Expanded palp - Eris militaris - Male
N40 03.312 W82 53.780, Columbus, Franklin County, Ohio, USA
August 22, 2006
Retrolateral view of expanded left palp. Temporary mount in petroleum jelly.

Images of this individual: tag all
Bronze Jumper - Eris militaris - male Bronze Jumper - Eris militaris - male Bronze Jumper - Eris militaris - male Bronze Jumper - Eris militaris - male Bronze Jumper - Eris militaris - male Bronze Jumper - Expanded palp - Eris militaris - male

Nice image. "Temporary mount"
Nice image. "Temporary mount" -- you used petroleum to hold it in position (it's not immersed)? Is that a microscope shot? If so, can you explain a little about what you are using (and magnification). I'm still limited to digital camera and Raynox converter lenses.

-K

 
Yes, with a microscope...
Sorry I didn't answer sooner. An emergency landed on my desk just a few minutes after posting the image.

It's generally bad to shoot these parts dry as they can get messed up pretty quickly by losing their shape and becoming fragile. Mounting them on a standard microscope slide with a coverslip also presents a problem because the part can get flattened or damaged. So I try to follow the technique described by Maddison in his Pelegrina revision, where the palp or epigynum is mounted on petroleum jelly in an alcohol-filled depression slide under a coverslip. Jelly allows for careful positioning and holds the part still while placing the coverslip.

(That's the idea anyway. The reality is: This is my first compound microscope, recently purchased. My first box of slides. First box of coverslips. And I can make one hell of mess. I suck. The results I present are usually decent because I keep trying until I get it right. I still suck though, and won't get much time to practice again until next winter.)

This particular specimen mounting is something of an odd-ball, so there's a little more to explain:

After I positioned and covered this one I held the slide over a small flame to smooth-out the jelly so it wouldn't destroy my lighting. I got too careless, too close to the flame, and the alcohol started boiling. I figured I would need to start over anyway, so I may as well see if the palp would expand right on the slide. Sure enough, it went POP!, and the jelly cooled fast enough to hold it in place in this state. Resulting image isn't very clean because of all this (and the palp isn't fully expanded), but it gave me the view I wanted so I didn't bother to clean and remount.

The microscope is an Olympus BH-2 (BHT body). I have 5x, 10x and 20x Neo SPlan objectives, and a 10x SPlan APO objective. Photos are taken with my 30D attached to the trinocular tube and use a NFK 2.5x photo-eyepiece, so actual magnifications at the camera sensor are 12.5:1, 25:1 and 50:1. This shot was taken with the 5x and is cropped slightly all around. Using the 10x objective, I couldn't fit the bulb+embolus in the frame. With the 20x objective, the sperm duct doesn't quite fit in the frame.

 
attaching camera to microscope
Hi, Jay--

Many thanks for your answer and detailed information. Are you trying for create permanent mounts? I don't know all the details, but I would swear that the other micro users whose images I've seen simply place the specimens or palps in a fine sand-like mixture (glass beads, I think). What they do with the epigyne I am not sure.

Can you give a more detailed reference/url to the Maddison doc that you mention?

Thanks in advance,

-Kevin

 
No, not trying to create anything permanent.
I should first point out that I consider the mounting shown here to be a total mess. I only bothered to shoot it because the angle was perfect for showing the bulb, embolus and tybial apophysis. I knew it would be difficult to get this angle again if I started over, and I just didn't feel like messing with it anymore. The time-stamp on this file is 3/8/2008, and I didn't bother to post it until you questioned the ID; that's how much I like this photo. :-)

So this photo is not a good example of what can be done with the method I described (or, rather, copied). And the extra details I gave are not something I would recommend following. There are better ways to fully expand a palp, and easier ways to make a total mess. Slides and coverslips are required due to the short working distance, which for my 10x and 20x objectives is less than 1mm.

Workflow of the "other micro users" you mentioned is probably somewhat described in this document by Levi. Photographing genitalia through a dissecting scope is certainly do-able for the larger spiders like Phidippus and even this Eris. My earlier palp photos of both genera were taken with a Canon MP-E 65mm at 5:1 magnification, which is roughly the same magnification as a 40x stereoscope. But catching all the tiny details of the smaller species requires better glass, greater magnification and more effective lighting control.

For a direct comparison, consider these palp photos of a Pelegrina proterva:
 
The first image, taken with a MP-E 65mm at 5:1 magnification, was about 800px high before resizing for upload, and probably looks similar to what you are seeing from other micro users. The second image, using a 20x objective for 50:1 magnification, is uncropped. Here is the larger version that I originally uploaded.

Full reference for the Maddison document is: Maddison, W.P. 1996. Pelegrina Franganillo and other jumping spiders formerly placed in the genus Metaphidippus (Araneae: Salticidae). Bulletin of the Museum of Comparative Zoology. l54(4): 215-368 Can be purchased directly from Harvard for around $25-$30.

And here's some fantastic news: I just found out a few nights ago that all of volume 154 (along with thousands of other very important taxonomic works) has recently been made available online here. Number 4 starts on page 237 of the PDF, and the 'Materials and Methods' section starts on page 243.

 
Establishing a scale reference...
One more question. I've been told that using a zoom objective offers certain useful benefits -- being able to zoom in on a detail without having to first find it again when changing magnifications.

On the other hand, with a zoom, I would not really have a permanent scale reference, would I?

I assume that in your sample image on the right you are using a fixed objective through which you previously viewed a known grid reference to establish a usable, repeatable scale reference. ?

-Kevin

 
Weird that the page changed
even the ftp link is different, but I guess I shouldn't be too surprised since that volume isn't even linked from the Bulletin TOC yet. The ink is definitely still wet at BHL.

I found this ftp link in my download history. The .PDF is still there.

Yes, usually the magnification in the first image would be enough, but you might hit a wall with some of the smaller females. Hard to say for sure. I've taken photos through my dissecting scope (Olympus sz40) only once, and the camera was handheld, so not much of a test. And not all optics are equal anyway, so if you're shopping around hopefully you can try before buying or work with a dealer who will let you easily trade.

You are correct about the scale reference with a zoom. You might do well to purchase a stage micrometer, and take a photo of that after every specimen photo. For my micro shots I use a spreadsheet created by Charles Krebs to provide the dimensions I need for a scale bar. If you haven't already, I recommend reading through his articles. His writing is as good as his photography.

Um... you lost me with that monoscope sentence. :-)

 
Kevin
Were you able to get the PDF?

 
Yes, I have a feeling that th
Yes, I have a feeling that they were uploading/updating the page as I was browsing. All formats were there last time I looked.

Have you found a listing anywhere of exactly which volumes are online?

 
Volume listing
click my 'Bulletin TOC' link above for the list of volumes currently online. Well, except for the volumes that are online but not yet on that list... :-)

Looks like volumes were just added, and the label being generated is a little different (better though) so they aren't sorted properly.

 
Many thanks, Jay. I just need
Many thanks, Jay. I just needed to read more closely your previous answer.

I've also added this information to the Nearctic Arachnologists' Forum (so that I can find it again) here.

 
Jay, you are a tremendous sou
Jay, you are a tremendous source of helpful information! I see the makings here of a useful article (almost complete, actually). I know one other user who works with two scopes -- one a low-power 3D stereo for dissecting and preparation as you mention, and then a somewhat higher-powered "monoscope" for (great) imaging.

In my case the budget will be limited to a single scope, stereo/3D with a zoom range going up to 45x. Let me ask you this: While the second, more detailed, image is fantastic, the first image (at least in this case) would suffice for a species identification, wouldn't it? [Well, rereading your posting, I think you already answered this question.]

I suppose the "mononscope" will give better images, if only because not being a trinocular, you can afford to spend more money on a better-quality instrument. ?

One last note -- thanks for the link to the online archives, but for the life of me I can't figure out what one clicks on there to view the individual volumes (all I see is the meta data) -- and many thanks to Harvard for putting this online.

-K

 
Hey
Kevin. You can also browse through Jay's close-ups here, as he often explains his technique, and see also the photography sections here.

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