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Re: NFC: Fishy Behaviour

In many species that guard their nests, such as cichlids, egg-eating is
very rare.  It typically happens when the pair is constantly being
threatened or otherwise stressed out.  The theory behind this is that the
pair "figures" that their spawn will be destroyed sooner or later anyhow,
and they might as well reclaim the energy.  There is a huge investment of
energy put into just laying eggs, let alone guarding them and rearing
them.  Food is scarce in tehn wild, and so they effectively steal the meal
from someone else.... 
Now, in here lies the answer as to why egg-scatters and such would eat
their own eggs too.  If the eggs are scattered over a bed of plants, some
will fall into corners where no fish will get to them. A nd some will,
unfortunately, land on the top where anyone whos hungry may eat some.  The
pair eats their own eggs, that they can reach, before anyone else can.
Therefore, they get a meal that their competitores would've, had they been
genetically programmed to say "no, thats my BABY!  I can't eat that!"
So, yes, there is an evolutionary advantage to eating your own eggs:
They're eggs that will e eaten by other hunters, so you might as well get
to ehm yourself first.

And, of course, eating eggs/fry is much safer than canibalising adults of
your own species.  Aside from removing them from the population and gene
pool, studies have shown that species that canibalise run a strong risk of
disease.  Especially true since the weak are the ones that often get
picked off.  And, if it can affect one of your kind, it can affect you.

Joshua L. Wiegert
NFC Lists Administrator                          JLW at pi_dune.net
www.geocities.com/RainForest/Jungle/1680/        owner-nfc at actwin_com
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On Tue, 30 Jan 2001 Ty_Hall at eFunds_Com wrote:

> Date: Tue, 30 Jan 2001 11:51:18 -0600
> From: Ty_Hall at eFunds_Com
> Reply-To: nfc at actwin_com
> To: nfc at actwin_com
> Subject: NFC: Fishy Behaviour
> I am curious, why do some fish eat their own eggs? This would seem to be
> detrimental to the survival of their species and thus, I would expect it to
> be more of a rare occurance then it is.
> Ty