Autor Thema: Bdelloid rotifer: Adineta vaga minor  (Gelesen 533 mal)

Goldfuss

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Bdelloid rotifer: Adineta vaga minor
« am: April 10, 2021, 13:18:28 Nachmittag »
After the study of microscopic life in moss recently posted by Martin Kreutz and Ole Riemann (excellent, as usual), I decide to present some of my recent observations in this field. My method of obtaining samples from moss differs from that used by Kreutz and Riesmann: I place the dried moss in a small jar to which I add mineral or distilled water until it is completely covered. After at least twelve hours, I shake the bottle vigorously for ten to twelve seconds and pour the liquid onto a petri dish. Normally, a good number of rotifers, annelids and tardigrades are collected. Some specimens are knocked out after this treatment (especially tardigrades) but many recover after a few minutes or hours. In my experience, many rotifers, annelids, and especially tardigrades, stay alive in the petri dish for more than two weeks.

I show two videos of one of the most frequently rotifer found on moss in the Iberian Peninsula; Adineta vaga minor,  (I'm pretty sure of the ID, but in my opinion the identification of bdelloid rotifers is one of the most complicated tasks for amateur and even professional spectroscopists). Surprisingly, in a sample prepared to film annelids, I found some eggs of this Adineta about to hatch. You can see the hatching of three eggs of Adineta vaga. All “technical” information, as well as a picture of the collection point, is shown at the end of the videos I apologize for not being able to express myself in German and for my poor English.

Adineta vaga minor video:
https://youtu.be/o45v_zyOKrs

Adineta vaga minor eggs hatching
https://youtu.be/863OEF2Rj90





SNoK

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Re: Bdelloid rotifer: Adineta vaga minor
« Antwort #1 am: April 10, 2021, 16:14:17 Nachmittag »
Die beiden Filme gefallen mir ausgesprochen gut. Sehr instruktiv, gerade der erste mit den eingeblendeten Bezeichnungen der einzelnen Strukturen. Da ich mir vor einiger Zeit eine Sony alpha 6500 gekauft habe, und sah, dass diese Filme mit der Sony alpha 6300 aufgenommen wurden, muss ich das unbedingt auch mal probieren. Mit welchem Programm wurden die Videos bearbeitet?

Stephan
Mikroskop: Leica DMRB
Objektive: Plan Fluotar und Plan Apo
Stereomikroskop: MBS 10
Kamera: Sony alpha 6500
Webseite: https://kralls.de

Ole Riemann

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Re: Bdelloid rotifer: Adineta vaga minor
« Antwort #2 am: April 10, 2021, 18:39:08 Nachmittag »
Hello Luis Carlos,

thanks for sharing your Adineta video and the interesting details of your extraction technique for microscopic animals from moss samples. It reminds me of how I sample the microfauna living in marine sediments.

You are certainly right about the difficulties in identifying bdelloid rotifers - I have only just started and have found Michael Plewka's website to be tremendously helpful: https://www.plingfactory.de/Science/Atlas/KennkartenTiere/Rotifers/01RotEng/E-TL/TL5RotatoriaBdel1.html

Best wishes

Ole
---------------------------------

Olympus BHS/BHT
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Vorstellung: http://www.mikroskopie-forum.de/index.php?topic=19707.msg149740#msg149740

Michael

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Re: Bdelloid rotifer: Adineta vaga minor
« Antwort #3 am: April 10, 2021, 19:26:26 Nachmittag »
Hello Luis Carlos,

great videos!
It is astonishing, that there are several eggs at the same spot. I suppose, each rotifer lays only one egg a time, so it seem to me, that several mothers share the same "nest". I never heard of something alike with rotifers.

Best regards

Michael

Gerne per Du

Goldfuss

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Re: Bdelloid rotifer: Adineta vaga minor
« Antwort #4 am: April 11, 2021, 10:56:29 Vormittag »
Thanks Stephan, Ole and Michael

Stephan: I use the free version of DaVinci Resolve, a powerful but complicated software.

Ole:  If it can help you in the identification process,, I start by trying to establish bdelloid genera: C. Ricci and G. Melone, Hydrobiologia 418: 73–80, 2000.
Often the result is simple frustration. If I can establish it (very simple in Adinetidae), I go to the page:  http://www.plingfactory.de/Science/Atlas/Artenlisten/RotiferEArtList1.html
My deep appreciation to Michael Plewka for the magnificent pictures and for the anatomical information that he includes in plingfactory.
The next step is to confirm it with Josef Donner's old text "Ordnung Bdelloidea"

Michael: The first surprised is me, especially considering the extraction method

Best wishes
Luis Carlos

Michael

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Re: Bdelloid rotifer: Adineta vaga minor
« Antwort #5 am: April 12, 2021, 10:48:21 Vormittag »
Holla Luis Carlos!

Your observation of the hatching eggs of the morphotype Adineta vaga is very interesting and probably important!

First, you showed, that the hatching of the eggs is synchronized. As the eggs are probably not laid simultaneously, there must be some mechanism, which suspends the hatching of the embryo until there are favorable conditions.

Second, there are more than one egg deposited at the same place. So the animals must prefer to lay there eggs in the vicinity of other eggs.

Both hypothesizes are  - to my knowledge - not discussed for bdelloids. This makes your observation very interesting.
I'm not a specialist for rotifers, but I observed similar behaviors for gastrotrichs. There are some species of gastrotrichs, which prefer to deposit there eggs in the vicinity of other eggs. A typical "nest" may contain a dozen eggs of different species:



The reason for this behavior may be, that a predator (mostly amoeba and tardigrades) is fed up with one egg and the chances to survive increase therefore for the other eggs.

Some other species may suspend their embryonic development before they hatch (for example Lepidochaetis zelinkai) when the conditions become unfavorable. As soon as the conditions improve again, they resume their development and hatch synchronized.
The reason for this may be, that this is a great tool to survive unfavorable conditions and rapidly build up a big population when the conditions are adequate again.
Especially when living in moss,  you always must be aware of desiccation and wetting again and again. So to me, a similar behavior for bdelloids makes sense.

This is a perfect example, where enthusiasts like us can contribute to the scientific knowledge, as scientists normally don't have the time to observe freely living microscopic animals. Thanks to your observation, all of us, who work with moss, should pay closer attention to similar eggs.

Best regards

Michael




Gerne per Du

Goldfuss

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Re: Bdelloid rotifer: Adineta vaga minor
« Antwort #6 am: April 13, 2021, 14:29:11 Nachmittag »
Interesting comment. In fact, Simon et al. (https://doi.org/10.1101/2020.06.16.155473) report that several specimens of Adineta vaga bearing a single egg, isolated in a petri dish, were laying eggs almost synchronously.
I agree with you that amateurs can make interesting contributions to scientific knowledge. In the world of astronomy, a good part of the new comets is discovered by amateur astronomers. In the field of microscopy we have Didier Chardez (1924-200) a non-professional scientists with relevant contributions on testate amoebae.
Personally, my goal is the observation of the wonderful microscopic life and the production of free videos that can be used for educational purposes.

Best regards
Luis Carlos