Tardigrades and polarized light (II) |
But now let's go back to our main topic, the polarized light.
Before actually making use of the respective switch we should pause for a moment and wonder
what we are expecting from this particular illumination. |
The eutardigrade Macrobiotus hufelandi has strong, curved stylets and fine stylet springs. |
The giant eutardigrade Adorybiotus coronifer is equipped with similar strong stylets. In this case the curvature is less pronounced and the stylet springs look quite different from those of Macrobiotus hufelandi shown above. |
The carnivore eutardigrade Milnesium tardigradum comes with comparatively weak stylets and extremely small stylet springs. When looking closer at the photograph you will notice that the stylet springs are resting in stylet sheaths. Possibly Milnesium tardigradum doesn't need strong stylets because it has a tendency to devour its victims as a whole! |
This heterotardigrade Echiniscus sp. reveals fine linear stylets, typical for all members of the genus Echiniscus. |
Batillipes sp., a marine heterotardigrade shows similar stylets as its terrestrial Echiniscus relatives. |
Once more, similar Echiniscus-style stylets of a marine Florarctus sp. heterotardigrade, but with stronger curvature |
So, with some species the stylets and in particular the style springs are not easily visible at low magnifications. The stylet diameters can be as low as a few micrometers (!) which is quite astonishing for a tool which must serve reliably for everyday object piercing and feeding. Hartmut Greven mentions in his tardigrade book that some of those stylets - even though being that much tiny - can be hollow, making use of the physical fact that a tube has similar mechanical properties as a rod of the same diameter. |
The chemical composition of the stylets |
Literature
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© Text, images and video clips by
Martin Mach (webmaster@baertierchen.de).
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