Adult Cyclops - Pregnant Female

Mitch640 · Post by **Mitch640** » Sat Mar 19, 2011 5:35 am

I have seen and read enough about these guys at different stages, to know what I am seeing now. This is an adult female with ovaries full of eggs.

1. A full frame shot. The brown line in the center is lunch in her gut. These animals have no heart, circulatory system or gills. They flex their muscles to propel fluids around the inside of the body. You can see it happening in real time. The two dark lines outside the gut are the ovaries, full of eggs. 4x.

2. The single spot at the front is the eye, out of focus here. You can see the eggs better in this shot at 10x.

3. At 20x, you can see some of the smaller life that follow the cyclops around from egg to death, then eat the body. These are Euglena.

4. The base of the body at the waist. You can see the end of the ovaries and where the tubes continue outside the shell. When ready, the eggs will be expelled at the ends of these tubes and kept in two eggsacs until they hatch. The body continues here, but it goes out of focus real fast. 20x.

5. Closeup of a muscle bunch, ovaries and the gut. All these are full frame. I don't know what the purple stuff is, it's part of the Cyclops. 20x.

NikonUser · Post by **NikonUser** » Sat Mar 19, 2011 6:07 am

Wow! Image quality is excellent, what a difference from a few months ago.

Not sure that what you call "lunch in her gut" is correct. This is more likely to be the actual ovary; the dark lines outside are better referred to as the uterus where the eggs are stored.

Note that the uterus (uteri?) open on the last thoracic segment. Also, she appears to be unmated; mated female show 2 sac-like spermatheca where the uterus opens.

Mitch640 · Post by **Mitch640** » Sat Mar 19, 2011 6:31 am

Thanks for the corrections Tony. Each time I learn more, it clues me in on what to look for the next time I find one.

My basis for the lunch call is, that every cyclops I have seen so far, has the brown center area that moves forward and back by muscular contractions, the naupli also have something similar. I have read that they contract the 'stomach' to force bodily fluids around the body. I even found one adult stage that had almost no food in the gut at all, if it is the gut.

As for the ovaries, or uterus, they only appear in adults with no external eggsacs, and the black spots seem to be the eggs. I have not found an adult male yet.

I would love to be able to keep one separated and alive, that had the eggs inside, and catch the same cyclops during or after the formation of the eggsacs.

As for image quality, I am getting use to it, but sort of waiting for the other shoe to drop. I have ordered some long handled polyester swabs to clean those little lenses in the arm, and my objectives, even better. I called about getting the trinocular head cleaned and the guy started talking about breaking the prisms and yadda yadda, so I decided I could live with dirty viewing prisms, as long as the straight through view to the camera is clean.

Mitch640 · Post by **Mitch640** » Sat Mar 19, 2011 6:58 am

Found this in a search, the anatomy of a female and it just happens to be this particular sub-species.

http://etc.usf.edu/clipart/47900/47955/ ... yclops.htm

NikonUser · Post by **NikonUser** » Sat Mar 19, 2011 7:13 am

Gut or ovary was a tough call; both occupy the mid-line of the animal.
Don't equate ovary with uterus. They are different. The ovary is where the germ cells divide to give haploid eggs (only one set of chromosomes). These tiny eggs then move to the uterus where they are nourished until they reach full size.
They then pass out of the uterus where, my guess, as they pass out they are fertilized and go from haploid to diploid (2 sets of chromosomes). But, I can't imagine why the female carries, outside the body, 2 sacs full of eggs. Maybe in the sacs is where the eggs are actually fertilized.

Mitch640 · Post by **Mitch640** » Sat Mar 19, 2011 7:20 am

Maybe the actual sprem sacs are reused as egg sacs?

This is only one sub-species, yesterday, I found pics of another one that has only one eggsac. Haven't seen one of those yet.

Would the sperm sac already be attached to this female? I have many other shots of her that I processed. maybe I can find it.

NikonUser · Post by **NikonUser** » Sat Mar 19, 2011 7:58 am

It's beginning to feel like I'm back at school writing exams.
The page you cited is from a 1916 book, interpretations have changed a bit since then. My ref. books are 1961 and 2001; interpretations may have changed since.

To clarify: The ovary is a single median structure lying above the gut in the 1st 2 thoracic segments. A pair of oviducts, one right one left, leave the ovary and open into the large branched diverticula (uterus) that clearly show in your images.

The fertilized eggs are carried in the egg sacs until they hatch (so that's why she carries them around).

Be very careful about identifying cyclopoids even to genus; identifying to species and subspecies is, to say the least, fraught with uncertainty.
Your specimen is most likely a Cyclopoid but to which genus it belongs would need an expert on the group.
In NA there are 19 genera with the suffix 'cyclops'; ranging from Acanthocyclops to Thermocyclops.

The key difference between the genus Cyclops and its closest relatives is: Leg 5, distal segment with apical seta and large spine = Cyclops; Leg 5, distal segment with apical seta and small spine = other genera.

Have not seen male spermathecae attached to a female but text book shows 2 dense sacs attached to the last thoracic segment where the uterus opens.

Mitch640 · Post by **Mitch640** » Sat Mar 19, 2011 8:09 am

Other mysteries about these cyclops is that there seems to be only one family in my tank. At least I have not found any that look different from these. I don't know enough about any of them to actually identify them, just if they look similar. The one I have have a long section behind the body and before the split in the 'legs'. where others I have seen on google searches don't seem to have that section at all.

fpelectronica · Post by **fpelectronica** » Sat Mar 19, 2011 8:23 am

Excellent images
Francisco

Mitch640 · Post by **Mitch640** » Sat Mar 19, 2011 9:05 am

Thanks Francisco. Cleaning the little lenses in the arm made all the difference.