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Fw: Ephippia - How do they know?
----- Original Message -----
From: George Davis <gwd at magpage_com>
To: <killietalk at aka_org>
Sent: Thursday, November 09, 2000 05:23
Subject: Ephippia - How do they know?
> Hi all:
> Here it is fall in the northeast and days are getting shorter and
> colder. But how do my daphnia pulex grown INDOORS know that? Just within
> the last week, I have been getting considerable egg (ephippia) production
> without having changed any parameters indoors. The lighting is on the
same
> cycle, and although they are within 5 feet of a small window, it does not
> let in TOO much light into the basement. However, it could be that the
> natural light that had been coming in during the summer was much brighter
> than the more subdued and shorter natural fall light. Any thoughts? It
> was my understanding that daphnia would produce ephippia when under
stress:
> too little food, over crowding, drop in temperature for example. None of
> those things have happened here. The cultures have not appeared to change
> at all except for the egg production.
> Now come the questions. What do I do with the ephippia to make them
> hatch? I have read that they need to go through freezing and thawing
> spells. I have been collecting eggs onto paper towels to store them and
> experiment. Since freezing doesn't seem to faze them, I thought they
might
> be a good candidate to ship to people in places that have not been able to
> obtain daphnia. The one time I just added water back to fresh eggs,
nothing
> happened.
>
> George Davis
> Wilmington, DE
>
> ---------------
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