SPIDERS No.41 – The Calamistrum

Images made through a microscope. All subject types.

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Walter Piorkowski
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Location: South Beloit, Ill

SPIDERS No.41 – The Calamistrum

Post by Walter Piorkowski »

Image

Image

Image

Image

Image 1
End of leg four showing the calamistrum on the metatarsus segment of the leg. The spiders abdomen is in the background.
Leitz UO 6.5X Achromat
Diffused fiber optic illumination.
26 images at .001 inch increments.

Image 2
Detail of the metatarsus leg segment and the calamistrum comb.
Nikon 20X Achromat
Diffused fiber optic illumination.
254 images at 1 micron increments.

Image 3
High magnification attempt at revealing the location of the opening in the hair that exposes the fine cuticular teeth. These comb the silk from the cribellum. The opened slit is visible where the hair is bent or curved. The cuticular teeth are beyond the resolution of my optical microscope.
Leitz UO 75X Apo., Oil, Plus mirror condenser. Full EPI illumination.
47 images at 1/2 micron increments

Image 4
High magnification shot of the last 3-4 hairs of the calamistrum at the tarsal end. The difference in the calamistrum hairs verses the three normal leg hairs is apparent.
Leitz UO 75X Apo., Oil, Plus mirror condenser. Full EPI illumination.
89 images at 1/2 micron increments

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


Spiders of the crebulate type have a silk producing organ called the cribellum. It produces tens of thousands of minute silk strands only 0.01 micrometers in diameter.
A comb like feature is found on the rear legs. However the hairs are far from the most interesting feature of the calamistrum. On the surface of the hairs, similar to seeing the corn seeds exposed when first stripping an ear of corn, is a row of micro fine teeth. These are the objects that actually comb the strands of silk, only 0.01 micrometers in diameter, into a wooly like strand.

Our subject is the same spider of genus Ubolorus that is in Spiders No. 40.


Walt

rjlittlefield
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Post by rjlittlefield »

Again beautiful work, Walt.

I have visions of you assembling a book, "Spiders: An Optical Atlas of Hairy Webslingers". Or some such. The title needs a little work, but I think you have the content well in hand.

--Rik

RogelioMoreno
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Post by RogelioMoreno »

Very nice set!

Rogelio

Walter Piorkowski
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Location: South Beloit, Ill

Post by Walter Piorkowski »

Thanks Rik and Regelio. Rik, keep working on that title. Not a bad idea.
Walt

Mitch640
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Post by Mitch640 »

I never made the mental jump from inches to millimeters, even though it happened here in the US when I was in my teens. And I certainly can't picture what 0.01 micrometers looks like. So how many of those fine strands can fit between the teeth of those micro combs? :)

rjlittlefield
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Post by rjlittlefield »

Mitch640 wrote:I never made the mental jump from inches to millimeters, even though it happened here in the US when I was in my teens. And I certainly can't picture what 0.01 micrometers looks like. So how many of those fine strands can fit between the teeth of those micro combs? :)
As a quick quideline, the wavelength of light is about 0.5 micrometers. At 0.01 micrometers, those fine strands are really small!

Assuming that last image is full frame, then its total frame width is about 0.22 millimeters (22 mm sensor width, divided by total magnification of 75*4/3). Each pixel is then 0.275 micrometers (0.22/800). The space between the microhairs on the hairs is about 2 pixels, call it 0.5 micrometers, so in theory about 50 of those fine strands side-by-side even between the smallest hairs on the hairs. Between the large hairs on the comb -- too many to think about!

See http://www.americanarachnology.org/JoA_ ... 1_p161.pdf for some further information on "ULTRASTRUCTURE OF CRIBELLATE SILK..." in the Journal of Arachnology.

--Rik

Edit: provided a better URL for the reference.
Last edited by rjlittlefield on Thu Mar 15, 2012 10:50 am, edited 1 time in total.

Mitch640
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Post by Mitch640 »

OK, now that is a picture I can see in my minds eye. Now I am wondering how a living organism can build something that small. Maybe we could train them to do microcircuits? :)

rjlittlefield
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Post by rjlittlefield »

That's being worked on.

--Rik

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