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Re: KillieTalk Digest V4 #633
Lee and Wright and all..........I know that sometimes there are severe skewed
sex ratios and it's not limited to Killies of course but in thinking about
the "nature" of things.......what guarantee is there that we are starting out
with a 50/50 ratio in the wild??? No one I have asked that has been collecting
in the wild was really prepared to say that there was a 50/50 % of this fish or
that......maybe in the wild there is a NATURAL 80/20 and we just happen to bump
that a bit to get a terrible ratio.
It's just a thought and not meant to argue. To make my point about
nature.....tolerate this a minute folks (warning-off killies). I saw a tank of
apistos about 2 weeks ago.......ready.........12' x 4' x 4'......I think that
is about 1500 gallons. There were maybe 8-9 different types of apisto's in the
tank and they maybe numbered 50 apistos..............the behavior we see in our
15-20-30-55 gallon tanks is perverted and exagerated and only begins to tell us
the real story. In this tank there is virtually no agression. Fish (males-----
guarding females) that would fight to the death in a 55 gallon simply nodded as
they passed in the BIG tank....they flared a little but no harm. The wild is a
completly different place I'm afraid..........
Now having said all that.........chemicals may be the cause of being skewed
too.........as Wright said........much to complex for the amatures I to be
scientific I think.....but quite a topic to fool with as a
hobbyiest........that's how some of stay in the hobby as long as we
have.....grab something and go fool with it........
You folks have a great day!
> Date: Thu, 19 Dec 2002 13:57:23 -0800
> From: Wright Huntley <jwwiii at pacbell_net>
> Subject: Re: Lets test it with DAG MON RE: Skewed sex ratios and Androgens
> Good points from both Bruce and Lee.
> Experimental design here is tougher than it looks at first glance. Let me
> use a somewhat ridiculous extreme to illustrate my point.
> Let's say some chemical, temperature, dissolved mineral, or microorganism is
> capable of skewing the sex ratio. Now, let's postulate that survival, with
> that factor present, depends on either acriflavin (and/or methylene blue),
> or the eggs all die and end up being consumed by fungus. David's experiment
> will not uncover the real culprit, but will tend to put blame on the dye(s)
> when they actually only permitted survival.
> IMHO, one needs an initial condition of high survival *without dye* to
> isolate the sex-skewing properties of the meds. Those survivors must have
> equal sexes to make the skewing tests meaningful. I believe this is an
> essential precursor to Bruce's "control group" with no medication, for
> example. If that situation means that the hypothetical factor, above, is not
> present, the results could show nothing at all. The skewing factor would
> still be hidden.
> I'm having some conceptual difficulty imagining a hobby-level experiment
> that will not tend to lead to misleading post-hoc-ergo-propter-hoc
> conclusions. This could be one reason we still don't know what causes
> unequal sexes after knowing there was an occasional problem for a quarter
> century or more.
> Help my muddled thinking out, here, please.
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