On Fri, 31 May 1996, Charles J. Beare wrote:
>
> One question, I am feeding mu U.gibba with daphnia and Cyclops'. How
> can I get them to propagate themselves?
>
Something I can really sink my teeth into! I assume you're
talking about how to propagate the Daphnia and Cyclops. First off, Ken
Cusson had a question as to where to obtain these little critters. Don't
buy them! You can get thousands of them from almost any standing body of
water. Just take a net (has to be very fine mesh) or a jar or to your
local fishing hole and scoop up some water. Look closely and you should
see hundreds of them swimming about. Right now is the best time to
collect them (at least here it is) because of the spring clearwater phase
(a phase where the most edible algae is available for the Daphnia). Any
stocked trout pond or something similar is likely to have large amounts
of these cladocerans. Just go to some place that is heavilly fished and
has relatively good water quality (no large algal blooms on top).
To raise these little guys, you should prepare an algal infusion
ahead of capture. This is even easier than catching them. Put a jar of
water in a sunny location with some natural fertilizer (such as fish
fertilizer, or if you keep fish, some gravel from the bottom of the
aquarium). Within a short shile, the water will become a light green due
to the algae. This is perfect food for your critters, just dump them in
and they'll be happy. Don't worry if it doesn't look like there's any
food, you'd be surprised what you find. You may find it easier to just
keep the Daphnia in the water you collect them in, don't need osmotic shock!
Reproduction of cladocerans is relatively simple. All Daphnia in
the spring and summer are female and they reproduce by parthogenesis ie:
no partner needed. If you look very closely, you should see the eggs in
the females near the 'back' of the body. If dark black spots start
appearing in the females brood chamber, this is a sign of overcrowding
and males are produced to cope with this stress. They then produce
ephippia (resting eggs) and that will be the end of your Daphnia culture.
We've found it much easier to raise and reproduce 'cyclops' in
the lab than Daphnia. First off, they transport much easier, and
secondly, they seem to reproduce much quicker. Just put them in a jar
and they should reproduce in time (by sexual reproduction).
Sorry to be so long winded, just thought I'd cover all bases.
Look out for cladoceran predators in your culture. Basically, if you see
anything bigger than your Daphnia, pick them out. Also, beware of larval
mosquitoes. You don't want to start a breeding colony of those!
Hope this helps,
Chris Teichreb
Department of Biology
University of Regina
Regina, Saskatchewan, CANADA
E-mail: teichrch@Meena.CC.URegina.CA