As we have already learnt in the April issue the tardigrade is going to leave its old cuticula after moulting. Typically it uses an opening close to the head (or 'neck') of the old skin. Some authors think that the tardigrades use their stylets in order to pierce the old cuticula. But possibly the erratic movements before moulting alone are sufficient to tear the old cuticula and to free the tardigrade. |
Tiger pigmented tardigrade |
The cuticula of this Ramazzottius oberhaeuseri has a net structure which is clearly visible: |
Tardigrade Ramazzottius oberhaeuseri directly after a moulting process. |
Save the tardigrade now and put it back on a wet moss cushion by means
of a fine glass pipette. Afterwards you will be able to study the
details of the cuticula without bothering anybody living :-) |
Fine structure of the cuticula of a
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Fine structure of the cuticula of a
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Fine structure of the cuticula of Ramazzottius oberhaeuseri. Top view of the cuticula of the hind body, seen at medium magnification. |
Fine structure of the cuticula of Ramazzottius oberhaeuseri.
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When combining the results of our investigations from two different perspectives we come to the conclusion that the cuticula can be understood as a network of slightly lens-shaped elements, a craquelé, like smelting ice. With respect to the mechanical properties this structure will provide shelter and will be able to allow some movement as well though it will be not very flexible. |
Hind part of a cuticula of Ramazzottius oberhaeuseri. |
An empty cuticala can be easily overlooked at low magnification, in particular
by beginners. You should try to enhance the contrast of the microscope
illumination as much as possibly, even by means of closing the aperture iris.
This will possibly spoil the optical resoultion of your fine microscope
objectives but will certainly help you to spot the empty cuticulas.
Try to touch and tear such an empty cuticula by means of fine needles.
You will notice that it has a rather high tensile strength - just keep in mind
that its thickness is in the range of one micron only! And you will find out
that it is not elastic at all, which is trivy of course, as this is the reason why the
tardigrades have to get rid of it. |
LiteratureThere are many scientific publications dealing with the fine structure
and permeability of the tardigrade cuticula and tardigrade epidermis.
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© Text, images and video clips by
Martin Mach (webmaster@baertierchen.de).
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