SPIDERS No.39 – A Discarded Exoskeleton Part 3 – Fangs

Walter Piorkowski · Post by **Walter Piorkowski** » Sun Feb 12, 2012 5:23 pm

Three different views of the fang exoskeleton plus a close-up of the venom gland slit.

Image 1
A rarely seen rear view of the fang exoskeleton. The cheleceral teeth are clearly visible in this view that the spider uses to mash its prey. Barely visible at this resolution is one of the venom gland openings near the tip of the foreground fang. Also please note the channel into which the rotating fang can pass for a tighter internal swing.
Olympus 10x S Plan Achromat, 162 images at 5 micron increments.

Image 2
End view of the fangs, again from the rear, clearly showing the slit like openings of the venom glands. Also notice the serrated edges of the fang reportedly used to cut the silk strands of the web. At the upper left are the tips of the cheleceral teeth.
Leitz UO 20x Achromat with Leitz Relief Condenser, 127 images at 1 micron increments.

Image 3
Front view of the fang exoskeleton. It is interesting to note the number of scales present on the surface of the chelicerae. Possibly from the spider, but more likely from a butterfly or moth dinner?
Olympus 10x S Plan Achromat, 115 images at 5 micron increments.

Image 4
Another unusual bottom view of the fang exoskeleton. The outside or frontal view would be to the upper right. Again notice the insect scales littering the surface.
Olympus 10x S Plan Achromat, 116 images at 5 micron increments.

Leitz Ortholux microscope
4X Leitz projection eyepiece plus 1/3x relay lens
Canon 50D
Zerene PMax stacking.
Processing in Photoshop, Bibble Pro5

I know that it is sort of cheating to show what looks like a spider where this isn’t one, but the details that this project afforded were worth it. I have always wanted to get a shot of the fang venom openings and so I started cutting away at the tiny exoskeleton until I could get a view that provided it. The thin translucent nature of the exoskeleton also provided some pleasing lighting. Enjoy.

Walt

Mitch640 · Post by **Mitch640** » Mon Feb 13, 2012 7:53 am

Walter. First let me say that these images are views I do not believe have ever been seen of spiders or their parts. Certainly not by me.

But I still can not see in the fangs, just where the venom comes from. Is it like a hypodermic needle, with a channel inside the fang itself, or something else? I can not make out a clear channel, if that's what it is.

Ah, it's on the side of the fang, near the tip?

Pau · Post by **Pau** » Mon Feb 13, 2012 8:44 am

Wonderful series, the second one is by far my favourite.

What is the Leitz relief condenser?, an epilluminator or a epi darkfield illuminator maybe?

RogelioMoreno · Post by **RogelioMoreno** » Mon Feb 13, 2012 10:37 am

Walter,

The second one is amazing, I can see the hole where the venom comes out.

Rogelio

Walter Piorkowski · Post by **Walter Piorkowski** » Mon Feb 13, 2012 6:58 pm

Hi Mitch. Alas I wish it were so. These images may be unique as they go, but only because they were created through the process of image stacking. Very similar and even more detailed images done by scanning electron microscopes (SEM's) are out in the literature. Take for example the book spoken about on this forum by Rik L., "The Biology of Spiders" by R. F. Foelix. I acquired a copy of it last week. It shows exceptional electron micrographs of spider body areas that I could only hope to imitate.

All you will see in these images is the outer casting of the spiders body, so don't feel bad that you can't see a venom channel. It was removed by the spider as it extracted itself. What did remain however does have the hole that the venom would have passed through at the end of the channel. Note that because the fang you see is completely hollow when we look into the hole we see through to the back side as well. That is why it is not as clearly defined as I would have hoped.

Hello Pau. The Leitz relief mirror condenser is a special tool that is part of the ULTROPAK incident light system. It will accept UO objectives of various magnifications above 25x. They have to be extracted from their standard ring condensers and placed into the relief unit. What it does is accept the light path and bend it to illuminate the subject at a sharp angle in a 360 degree pattern.

Hi Rogelio. If you can see them then I have accomplished my goal. Thanks.

Walt