Krapanj (IV) - or male trouble or, possibly, a tardigrades' #MeToo ?

About 12 years ago, im August 2006 we had featured the anatomy of a Macrobiotus hufelandi male water bear. In this old issue you will still be able to comfortably click through the tardigrade male anatomy.

With respect to the marine tardigrades it became much more difficult to discern between males and females. In the beginning the visualization of analogous detail images appeared to range beyond our technical possibilities. Please just keep in mind that such a croatian Florarctus male is measuring not more than 0.1 mm, whereas the Macrobiotus male can easily reach 0.4 mm in length. But in the end it worked out.

For a start let's have a look look at the total view image of a Florarctus sp. male tardigrade below. At first sight (10fold objective) it doesn't reveal much detail. You will neither perceive the typical, thin "potatoe chip coat" of the Floractus sp. tardigrade nor its eight legs. And there are many fine structures which appear to be not exactly self-explaining. The head filaments can be seen on the left side of the image, though already being partially out of focus. The read marker square is referring to the text further below.

Florarctus sp. (possibly Florarctus hulingsi) male. Total view. Body length ca. a tenth of a millimeter.

Now let's zoom in towards the red marker square. You will note the roughly globular heads of numerous sperm cells and - faintly - the tails of those sperm cells:

Florarctus sp. male. Zoomed into the red square of the previous image. The red arrows are indicating the region which is containing the sperm cells.

In order to improve detail visibility we are going to use a trick, just by converting the image to its negative. This will help as a preparation in order to understand the final (video) visualization on the bottom of this page:

Florarctus sp. male. Same as previous image but inverted to its negative.

Well, as you will know already, an image might be better than 1000 words. And, even better, a video might be better than 1000 images! The sperm cells are actually moving vividly within the tardigrade:

It becomes clear that the male is virtually boiling inside its body! And this might possibly help to understand male behaviour in general, even the - sometimes very inappropriate - behaviour of the Homo sapiens male. Nature is using the Homo sapiens male as well as the tardigrade male, both as transporter media for its never ending global DNA war ...

© Text, images and video clips by  Martin Mach  (webmaster@baertierchen.de).
The Water Bear web base is a licensed and revised version of the German language monthly magazine  Bärtierchen-Journal . Style and grammar amendments by native speakers are warmly welcomed.

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