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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
> 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
> 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
> 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,
> happened.
>                     George Davis
>                     Wilmington, DE
> ---------------
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