Difflugia lobostoma parasitism
When I was trying to identify some Difflugia specimens, I broke their shells by pressing the coverglass with a needle. With a little luck the nucleus comes out of the shell and can be observed. I use this as a key character for determination between D. gramen and D. lobostoma. When I broke a shell of what was apparently a test of D. lobostoma, because of the structure of the nucleus, a Rotifer came out of the shell together with a rotifer egg.
De Smet, W.H., 2006. Asciaporrectidae, a new family of Rotifera (Monogononta: Ploima) with description of Asciaporrecta arcellicola gen. et sp. nov. and A. difflugicola gen. et sp. nov. inhabiting shells of testate amoebae (Protozoa). Zootaxa 1339: 31–49 (2006)
This is the young rotifer (above) together with the nucleus (below) and zoöchlorellae which slipped out of the broken test. The test was 161 µm long, the egg was oval (not visible here) and 49 µm long. The rotifer when stretched 129 µm and the nucleus 44 µm.
A second shell of D. lobostoma also contained a living amoeba and a young rotifer. This rotifer has zoöchlorellae in his stomach. This phenomenon remembered me of some older drawings which I made in the seventies. In this case I had seen several specimens of D. capreolata with many rotifer eggs and also young rotifers. I think the rotifers come out of the eggs and eat a part of the plasm body. The rotifer in D. lobostoma resembles the one which I noticed in 1977 in D. capreolata.
Difflugia capreolata – specimen upper- left with three rotifer eggs in its shell (1977).
A Difflugia capreolata with 13 eggs and two young rotifers. B Deformed nucleus of D. capreolata C Rotifer which came out of the test. D Rotifer egg E Young rotifer with zoöchlorellae F Chewing apparatus –mastix- of the rotifer.
I have seen the following: a An active specimen of D. capreolata with in the test (between body and fundus) 4 eggs with a young rotifer. Eggs ca. 70 µm long and rotifer ca. 160 µm. b An empty test of D. capreolata filled with 13 specimens of a rotifer (Proales sp.?, one big specimen and 12 small ones). The big rotifer was ca. 210 µm long. c A test with 3 eggs and 2 active rotifers. In the test also a piece of protoplasma with nucleus. The plasma formed pseudopodia. d A test with 1 rotifer and 4 eggs, including protoplasma. e A test with 2 rotifers and 13 eggs (see drawing A above) and protoplasma with zoöchlorellae. Both rotifers had zoöchlorellae in their stomach.
I also observed that D. capreolata sucked rotifers. Once I saw a specimen which emptied a rotifer in ten minutes!