How to create daphnia ephippia in order to use them as artemias' egg

[Italicus]

Hello everybody

now, i have never been lucky in culturing daphnia, they never suvived more than a couple of month, so how can i avoid to buy new starters of daphnia every single times? considering the fact that often they don't come alive?
the solution may be...daphnia epippia!!!
now, we all now that daphnia, very similarly to artemias, is able to produce eggs, usually 2, that are able to survive for long periods without hatching, but, although is very easy to find artemias' egg, it is very difficult to find daphnia ephippia.
here in london is very easy to find daphnias in the shops and it is possible to buy starters of daphnia magna very easily. so my idea is to voluntary make daphia magna lay ephippa so to use them when in need, especially when my cultures crash.
now what i am asking is: do somebody know how to produce ephippa? i know what makes daphnia lay them, but how do you need to treat and store them so that when you put them in water they actually hatch? do you need to dry them with the dead body of the adults? dry them at hot temperature, room temperature or freezer temperature? do you need to freeze them so to simulate a winter cold?
and once you want to activate them, how do you make them hatch?


i am sorry in the message is very confusing, i tried to put together my thought, plus it is 3:00 am, i can't sleep and i am writing almost blindfolded cause my glasses broke so tomorrow i will probably regret what i wrote

cheers

 

[Kaysie]

I know without a long photo period, and with cooler temps, daphnia are more likely to make ephippia. I've never done it intentionally though. Hopefully someone else can chime in with some advice!

 

[stanleyc]

This should answer your questions.

http://limnoreferences.missouristate.edu/assets/limnoreferences/davison1969.pdf

 

[Italicus]

thank you stanleyc, seems to be a very useful pdf, i will add it to the results of my research on my university database, hopefully i will able to reed them all once i finish my exams

 

[Italicus]

sooooo, exams are over so it is time of experimentation

first of all thanks stanleyc, your article was the most useful of all, i also find this article that seems very helpful Hydrobiologia, Volume 67, Number 2 - SpringerLink , but it is impossible to find for free

so now that the reading time is over, i bought some daphnia from a pet shop, they are the one sold also from amtra amtra premium live - Lebendfutter von höchster Qualität / Produkte für das Aquarium / Zierfischnahrung von amtra system

some f them have eggs that is good, i putted them in a little tube, with few drops of milk as food (the only think that i have around, it is almost impossible to find fresh beer yeast in london) and i putted the tube in a very dark place, this should convince the females to produce males and so ephippa.

i'll keep the topic updated for who is interested

 

[Azhael]

I recently managed to hatch the astonishing amount of two daphnia from ephippia xD Hopefully there will be lots more as i have plenty of ephippia.
A good friend sent me some Daphnia which all arrived dead leaving behind ephippia. He also sent me some ephippia from one of his ponds. I devided them into three containers. One in the fridge, one in the dark and one i put directly under strong light. From the one under the light two tiny Daphnia just hatched today, and i´m hoping for more. The other two batches will be put under the light in a week or so and from what i´ve read they have a better chance of producing more young Daphnia.

 

[Italicus]

it actually seems that the best way of making the eggs hatch is removing them from the ephippium, becouse is the ephippium that stop the hatching

 

[Italicus]

Rodrigo, keep also in mind that chilled ephippa seems to require the double the light to activate in comparisong with ephippa stored at 24 C

 

[caleb]

it is almost impossible to find fresh beer yeast in london

You can use bread yeast. Most UK supermarkets will sell you fresh yeast if you ask at the bakery counter (some will give it to you for free!). Dried yeast will work OK too.

 

[Azhael]

Well, it´s 22 little daphnia now, and i haven´t used the other two lots. From what i´ve been reading it seems that you are right and a cooling is not necessary nor probably benefitial. I´ll still try the cooled sample, though, no point in throwing it away.

I´ve used dry yeast with decent results. It should be easy to find in supermarkets.

 

[Italicus]

the only dry yeast that i have found in here is a white powder that doesn't make rise anything, not even a cake, and i honestly don't think it will be of any good for daphnia, furthermore, no food brings to the production of ephippa too, so the drops of milk should be enough for the production of males and ephippas.

two daphnia have already ephippa in them, but are completely black, and if i am not wrong that means that the eggs are not fertilised.

 

[Italicus]

little update on the daphnia,
most of the adult one are dead, probably due to the transport and i am not sure of what they eat, they were a strange orange colour. on the bright side, i have plenty of newborn.

I have harvested 3 ephippa until now, that i putted to dry in the dark.


one curious think that i have observed is the behaviour of the daphnia. they spend all the time in complete darkness, apart from the few seconds/minutes that i check them once a day. they stay mostly in the low part of the tub, and when i bring them to the light, the start to spin very rapidly, i honestly don't remember to have ever seen such behaviour

 

[stanleyc]

Keep the updates coming, I'm very much interested in your results.