Hunting

[Marek Mis]

I've somewhen been observing the worm hunting rotifer (Keratella quadrata). I'm enclosing five pics from this action. I haven't used any flash, just brigfield and 400 ISO. The worm moved very quickly so I've only managed to take few photographs. On the third, fourth and the fifth photo you can see rotifer inside worm's body, in the various parts of its "stomach".

[rjlittlefield]

I have never seen this before, and the photo series is great! I keep scrolling back and forth to see the action from different viewpoints.

I assume that the first and second images show the worm's head from "bottom" and side views?

How many rotifers do these worms eat, and how long does it take for the rotifer to break down?

--Rik

[Marek Mis]

Hello Rik,
Thank you for your comment.
You are right - the two first pictures show the worm's head. I don't know how many rotifers they usually eat. My observations didn't take long time.
The way of hunting is very interesting. The worm slowly approaches to the victim and when it is very close, its pharynx very quickly expands and acts like a vacuum cleaner. This last moment acts very, very quickly. I've observed that this worm feed not only rotifers what you can see in the next two images.
Regards
Marek