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I was going through some of my lab notes from college and found something that might be germane to Utricularia cultivation.  I used to work with Daphnia pulex on phytogenetics and sexual reproduction.

D. pulex is a fascinating little creature that reproduces primarily through parthenogenesis (essentially cloning) so all it’s offspring are genetically identical to their mother/sister.  So if you have one Daphnia it will quickly multiply and make copies of itself…very useful when you need to study the effect of environment on a specific population.  But I digress.


Materials:  500ml beakers (any # will do), several liters of purified water (distilled water is lethal to Daphnia-think osmosis), and flagellated algae culture such as chlamydomonas, lights on a timer.  Oh yeah, an eyedropper to catch the little boogers.

Methods:  Aliquot 400ml of water into each beaker, place one D. pulex in each beaker.  Set the beakers on a 14/10 light cycle and wait for the population boom to begin.  Keep the water fairly cool to control population growth; water temps over 70F will cause the animals to decline and switch to sexual reproduction.

Results:  The Daphnia will reproduce like crazy and the tiny clones are perfect to feed to flooded utrics.  Frequent water changes are recommended to prevent overpopulation and stress.

This setup can be contained on half of the lower shelf of your average fridge.

I recommend animals from resting eggs...the eggs can be sterilized with a weak bleach solution.  That way you won't have to worry about the bugs being vectors for plant diseases.

Let me know if anyone tries this out.

I raise daphnia for my fish and plant collection right now, I'm use a 5 gallon tank. Its water I got from my fish tank which has been cycled. I put algea capsule from the local health store. And I couldn't find dapnia at my local pet store, so I had to order from the internet. They are everywhere. Once a week I take most of the population out and feed them to my fishes and plants. THey are so useful, when dey are called water flea. Also brine shrimp is useful, but it can't be fed to the plant because the way i'm cultivating them is their water solution made of some salt.
I had some water creatures to feed my utrics, such as Daphnia (don't know the species) and cyclops, and various others (taken in a pond, then raised), but they didn't survived the moving (3 months in a closed container, with no light). I should try to get some back before automn... Do you know if all the Daphnia species have all the same reproduction speed (average)? I'll try to ID them as soon as I'll have access to the university library.

Do these creatures can be used as food for any kind of fishes (well, small fishes)?
Daphnia, can be used to feed small fishes. I give my fishes daphnia and brine shrimp every once a week. Sometimes, a Daphnia will go unseen in the bottom heavily planted and reproduce every once in a while. But then in about a couple day, they will be gone, a delicious meal for the fishes.
More info on Daphnids

Fall photoperiods and decreased dissolved oxygen levels (algal blooms) cause daphnids to switch from parthenogenesis to sexual reproduction.  The parent animal dies and its carapace closes around the two resting eggs...(the whole assembly looks a bit like a saddle or a purse) turns brown and sinks to the bottom of the lake or beaker.  These resting eggs are very durable, I've found viable eggs in 100 y.o. sediment!

Whats the point of all this?

1. The small offspring are the right size for U. longifolia and livida.  They grow quickly and when they grow larger than a period, it may be more difficult for the utrics to take them.  So time the reproduction (through temp control) to coincide with tray flooding.  Also, harvest clones as soon as they depart from the mom.  You can see the embryos developing in the mother since daphnids are clear for the most part. If they look too large to fit in a bladder...pull them out with eyedroppers...drop them on some tissue and feed them to your sundews when the excess water is removed. My capensis loves them!

2. The resting eggs (if you can find them in the mud) are perfect ways to begin a culture of daphnia or store them when you have to move.  Sexual reproduction can be induced in culture by adjusting temp and photoperiod; so in case you move you might be able to take some with you.

Utrics with smaller traps can and will take euglenoids and paramecium.  You just need a cheap microscope and to feed the euglenoids a small green algae.

Does this make my utrics grow better?  I don't know.  I find it very rewarding to see these cute little animals disappear from the trays that house my utrics.

Has anyone tries feeding "vinegar eels"? these are about the right size for Utrics with small traps. They are also very eay to culture.

I am sure I saw a reference to useing these as food somewhere...

Cool name, vinegar eel, never seen them or heard of them. Are they actual eels or what? I'll look this topic up i'll post something about them in a hour or two.
</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Survey a large number of vinegar eel websites and it becomes apparent that there are as many ways to grow these vinegar eel cultures (nematodes, actually) as there are sites with information on them. Some recommend growing mediums that are mostly water, others insist that solutions containing mostly vinegar are better. A few suggest growing them in the dark, others in the light. A few claim the eels don’t need oxygen, others insist they do. The one thing they all agree on is that as valuable as the eels are, harvesting them as food for betta fry is difficult. I decided to conduct some experiments to determine the best growing medium and attempt to develop new harvesting techniques. The results were surprising.
To determine which concentration of vinegar to water induces the fastest, healthiest growth, I inoculated three different growing solutions with the same amount of vinegar eels:

solution 1 = three parts water to one part apple cider vinegar
solution 2 = an equal amount of water to vinegar
solution 3 = one part water to three parts vinegar.

Each solution was also given one teaspoon of sugar and a one-cubic-centimeter piece of apple. The cultures were grown in long-necked 12-ounce beer bottles at an average temperature of 70 degrees.

After three weeks it was clear that the vinegar eels grew best in solution 3, the one-part- water-to-three-parts-vinegar solution. The mostly-water solution had very few worms in it and those that were present acted listless. The number of worms had decreased from the starting inoculation. Also, the solution had an unhealthy milkiness to it that I assume was the residue from decayed eels. The equal-parts-water-and-vinegar solution was only slightly better. However, the number of eels in the one-part-water-to-three-parts vinegar had markedly increased and they swam around with great energy. From this experiment it appears that solutions greater than fifty percent vinegar are to be preferred. However, the fact that many people have had success growing them in weaker solutions suggests that in the long run, vinegar eels may be able to adapt to a wide range of conditions. With this in mind, I suggest that anyone beginning a vinegar eel tank should start with the same growing medium in which their starter culture was raised and repeat these experiments to determine for themselves the best solution.

Two sets of the solutions tested above were prepared with one grown in the dark and the other in a normally-lit room. I could not detect any difference between the two after three weeks. This indicates that light is not a significant growth factor.

While conducting these tests, I observed that the vinegar eels congregated near the surface of the liquid, particularly toward the edge where surface tension curves the liquid up the side of the container. I assumed this preference indicated a desire to be as close to a source of oxygen as possible. With this in mind, I set up a one-gallon, sealed container with a very shallow depth of culture to maximize the amount of surface area available. Vinegar eels in this container appeared to increase faster than in the tall narrow containers of the first test. This lends support to the theory that the eels require oxygen to flourish. I noted that in this container, the eels had a greater tendency to inhabit the entire volume of liquid rather than fighting for room at the surface. I assume this is because the greater surface area permitted more oxygen to be absorbed into the liquid.

I tried the three commonest methods of harvesting and found them all unsatisfactory. Filtering through coffee filter paper was slow and many of the smallest worms wriggled through and escaped. Using various sponges to entrap eels was even worse. Washing the acidic growing liquid out of the sponge lost most of the worms and many of those remaining were damaged. The procedure of lightly corking the narrow neck of a bottle with filter floss then filling the top with clear water for the eels to swim into, thereby washing themselves, works but can take overnight to collect enough eels for a collecting. There had to be an easier, faster way… it turns out there were two.

(1) Take a small test tube, the ones used for testing ammonia levels are fine, use tape to attach a six-inch-long loop of wire or string to the open end below where the cap fits, fill the tube with growing medium siphoned from the area with the densest numbers of eels, cap the tube, and twirl it rapidly around a finger for one minute. Because the eels are heavier than water, they will be forced to the bottom of the tube where their tendency to wriggle will cause them to form a tangled knot. Quickly strain this knot of eels out and add it to the tank where they are needed as food. The knot untangles in 30 seconds to one minute and disperses. This technique works best when the nematode concentration in the test tube is high. A variation on this idea is to fill two tubes with eel solution and tape them to the bottom of a salad spinner. One minute’s spinning produces two clusters of eels that are easily strained.

(2) As quick and easy as the above technique is, the vinegar eels growing in the large-surface-area gallon container presented an even easier solution to harvesting them: vinegar eels climb. Two days after starting the gallon container, I noticed the sides were covered with a fine spider web of thousands of worms. Hundreds could be collected as easily as microworms climbing up the sides of their containers of oatmeal. Regrettably, this behavior is erratic. About half of the time there are enough eels on the side of the container to collect. The other half of the time the sides are clean. I’m currently experimenting to determine how to induce them to climb on a more consistent basis. So far they don’t seem to be attracted to or want to avoid light. Tilting the container to wet the sides usually causes them to climb within ten minutes, but this isn’t always reliable. If the secret to making them climb can be cracked, vinegar eels could supplant microworms as the food-of-choice for betta fry.

One last experiment I conducted was to test how long vinegar eels live in the neutral PH water of a fish tank. In spite of reports claiming that they live for days, this test showed that ninety percent were dead after only 36 hours. I was careful to avoid any physical trauma and made sure that there was no thermal shock involved that might have shorted their live spans.
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After reading that, I am still completely confused what and how you get them. I think I'll just stick with my daphnia.
  • #10
Nematodes are a naturally occuring resident of most soils...they can be quite detrimental to the roots of many CP's. I actually use U. sandersonii as a nematode control in my sundew pots, can't have those things chomping down on my roots. There are also predatory nematodes that eat the bad ones, if you prefer to keep your CP cultures pure.
  • #11
A nematode that is useful are microworm. They are very very small, and can be fed to ultric as well as any of your fishes.