Sunday, September 29, 2013

Box jellyfish Eyes

One quirk of the box jellyfish is that they have eyes. These eyes aren't quite like ours, but they are more advanced than you would think. 

It is not understood how box jellyfish have eyes, and yet they have no brain. They don't have anything to process or make sense of the images they are receiving. In fact, scientists questioned whether or not these eyes were even functional for some time. But recent tests have suggested they do in fact work. These tests include setting poles of various colors and transparencies into a tank of box jellyfish. In tanks with clear or light colored poles, the jellyfish ran strait into them. In tanks with black, solid colored poles, the jellyfish actually avoided them! This really brings out the mystery of how these jellyfish work. Perhaps they are smarter than we think! 

The reason I bring this up is because a small box jelly medusa was created a few days ago, in one of my polyp cultures of Carybdea rastoni. I decided to examine this one under a microscope. From there, I was able to really examine these eye structures. The jellyfish happened to be positioned so these eyes were "looking" right up at me. Shivers went up my back, even though I doubt it will be greeting me any time soon.

Above are two photos of the box jelly. The first is an overall shot of the jelly. At the time, it was a little balled up. The bottom of it is facing up, though. The second image is a close up of the eye structure. 

Sunday, September 8, 2013

What Makes Polyps Strobilate?

A few months ago I posted a few posts on some cold water Moon Jellyfish polyps I found. And I also posted how I lost all of my warm water polyps. Well, I have been making due with the cold water polyps since then. I've done a good bit of experimenting with the polyps. I find that they don't mind war, water at all. In fact, they seem to be fine with going from our ambient temperature (nearly 70 F to 55 F!) I have been really trying to figure out what gets these polyps to strobilate. There are a few things you should do when you have polyps and can't get them to strobilate. 

The first thing you want to do is figure out if them polyps have every strobilated in your care before. If they did, what conditions were they under. In my case, these polyps strobilated on their own three times last winter. 

Now you start to experiment. If you have seen them strobilate before, try to replicate the conditions they were in. If not, try some of the common methods of strobilation induction. Common methods include,

1) Bringing the temperature down for two weeks and then bringing them temperature back up to simulate winter and spring.

2) Doing the reverse and simply bringing the temperature down and holding it until they strobilate. 

3) Adding Lugol's Iodine to the polyp water. For this method, turn the flow off if there is some, and add 3-5 drops. Iodine levels increase in spring, and the polyps recognize this. 

4) Your own experimentation. There are other methods of strobilation induction. Some include shaking the polyps for several days (on a shaker table, no need to wear out your hands), exposing them to light for a time and then darkness, or reverse (particularly hydroids). 

In my case, I tried all but the light period method. I started out not having a chiller, so I couldn't drop the temperature. I was afraid I would kill my polyps if I brought the temperature up anymore. So I decided to try iodine. I did this several times in varying amounts, and it never seemed to work. I took some polyps and set them in a small bottle. I put this bottle on top of an air pump so it would shake the polyps constantly. This had no success either. Finally I got a chiller, so I decided to lower the temperature and bring it back up. That method is one that works on almost all Moon Jellyfish. I lowered the water temp to 60 for a week and then shut off the chiller. No strobila. I gave the polyps some time to rest and then decided I would chill them at 55 for two weeks. So my chiller isn't very powerful, and it is about 80 outside here, so my chiller fluctuates between 55 and 60. Right at two weeks I began to notice the polyps were elongating. So I left the chiller on. Within a week, they began to form full strobila. And then the onslaught of ephyra began. I have never seen so many ephyra in my life! I must have 1000-2000 right now! My polyps really paid me back for holding off all spring and summer. Now I need to build more tanks for all the ephyra.
Only the beginning!

So to wrap up, I believe the chilling induces strobilation in this strain of Moon Jellyfish. I can't be certain until I try again, though.