Re: f1 spawning

[Frauley/Elson <fraulels@minet.ca>]

IDMiamiBob@aol.com wrote:

> In the wild, fry "grow out" on a very broad-spectrum diet.  In our tanks, we
> tend to feed them BBS and pat ourselves on the back for our good husbandry.
> There are too many nutrients necessary for any vertebrate species to flourish
> for this to be an effective practice.
> Gary had the following thought:
> 
> <snip>> Maybe wild males with no territorial/spawning drive get driven out of
> desirable habitats, and effectively culled.<snip>
> 
> Over the millenia, DNA with no desire to propagate itself will long ago have
> been culled.  Face it- the only reason we exist {theological justifications
> excused) is to duplicate little strands of nucleic acids.  Any DNA which
> doesn't reproduce extincts itself.  A reproductive drive is essential for
> survival of the species.  Gary's unmotivated fish would have been all but
> genetically culled long before modern times.  Only one in a zillion fish would
> be born with this non-desire gene.
> 
> My explantion is only theoretical.  YMMV.
> 
> Bob Dixon

Bob, 
So much for thinking online :-)
My only addition is this: 
cacatuoides, wild and selected, never gave me a problem, and other than
the easyish taeniatus Moliwe, I haven't seen this problem with
'whitewater' fish. Blackwater - yes, constantly. But, I feed my fry bbs,
microworms, and crushed flake, and I raise them with chunks of wood and
tons of plants in their tanks. It isn't a natural diet, but it works for
'generalist' wild fish and f-1s. It doesn't work for highly specialized
fish from narrow ranges, at least not on the surface. Maybe it's
perfectly adequate, but it's possible what's missing is what we're
missing here.
On the surface, there does seem to be a correlation between adaptive
specialization and difficulties with F-1. With apistos, it would seem
connected to harem spawning specialists. It could also be these fish are
easier to physically stress out. I can only offer questions.
It could be dietary, but if people can remember spawning triggers
they've used for F-1 or more spawnings of highly adapted fish, it might
point us to other explanations as well. Males who don't court, display
or fight among themselves are very common among captive bred
Pelvicachromis. I'm told the pros who 'mass' produce them in Europe dose
them with hormones and have no problem. The DNA may have the info, but
what is it that makes the trigger for it so weak in some captive-bred
dwarfs? 


-Gary


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