One last rotifer video

[Pat Thielen]

All right -- This is it. I thank you all for putting up with my rotifer obsession of late. I promise I'll get better, or seek therapy if I don't. This video was shot using brightfield with magnifications of 40x and 100x (plan 4x/.1 and plan 10x/.45). As usual they were photographed using my ever so handy Nikon d810 and I used Adobe Premier for the editing and such. As always let me know what you think; input is always good and often makes for some very interesting discussion.

If you look closely you can see bacteria caught up in the rotifers' feeding currents. These are really cool animals!

[McConkey]

I think we will all be at a loss if you back off from your obsession! I've really been enjoying these videos and find it fascinating to see so many grouped together. I've never seen this many together before and it got me wondering about some stuff.

Hopefully someone can shed some light.

Are they social? The seem to ignore each other and not really interact despite being in such large numbers.

When they are grouped together like this do they have a heard mentality? Alpha male? Do they get territorial? Protect the females from threats?...etc

Your video's showed a really nice diversity in the size of these guys too, is size purely based on age? or does gender play a role? Can we tell male from female in this video?

Thank you for sharing these wonderful videos!!!

[Crater Eddie]

I too am enjoying your rotifer roundup!
CE

[actinophrys]

This is a nice video with a lot to see in it. It evidently has a few different types of bdelloids; normally I wouldn't claim I could identify any, but from 1:10-1:20 there is an unusual one in the lower right I think may be an Adineta, from the way it slides without any evident wheels instead of stepping or swimming.

And there is also some light on the question left from the previous thread. It is not evident while the rotifer is contracted, but at 2:20 the one shows a round bubble at the cloaca, which then abruptly contracts and disappears. Presumably it takes some time before it fills enough to be seen again, or maybe is also limited by the way they move around, which depends on muscles to pull parts in and hydraulic pressure to push them out.

McConkey, these are all female, and you can often see the paired ovaries on either side of the gut. The linked thread has some discussion on whether there are ever males, but at the very least they would be very exceptional. There would have to be some difference with age, but for the most part the different sizes here seem to reflect different types. I haven't heard of any interaction between them, though this kind of feeding is often more effective in groups; some other rotifers form colonies or at least settle together, as do ciliates like Vorticella and its relatives.

[Francisco]

Very nice video

[JimT]

Pat, super video. I often see several rotifers in a specific sample but never a "Herd" like this.

McConkey, these are all female, and you can often see the paired ovaries on either side of the gut.

Actinophrys, you certainly know what to look for.

[McConkey]

Actinophrys - Thank you for the detailed response! I took a look at the thread you referenced, i hadn't looked at in a few days so didn't notice the discussion going on! Duuuh! I should start to pay more attention! Really really interesting stuff!! Beyond fascinating and as MichaelG said in the other thread, the more you learn the more you realize just how much there is! Thanks again for the info!!

Again, Awesome videos Pat! Looking forward to seeing more!

[MichaelG.]

And there is also some light on the question left from the previous thread. It is not evident while the rotifer is contracted, but at 2:20 the one shows a round bubble at the cloaca, which then abruptly contracts and disappears.

Thanks for that observation ... Your analysis makes good sense.

MichaelG.

[vasselle]

Bonjour
Très belle vidéo
Cordialement seb