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Re: Sibling predation (was: hormones?)

Rather then a 'survival strategy' much more likely
that the strategy consists of getting a wholesome
balanced meal, i.e., eggs are good food. 

jake
--- James Honaker <tercer at latte_harvard.edu> wrote:
> 
> Tyrone wrote:
> 
> >I have had group of gardneri spawn and get quite a
> number of fry
> >grow up in the tank seeing no decline in egg
> production. Once the
> >fry began to mature the egg production went down
> and no new fry
> >emerged. I watched and saw the younger fish follow
> their parents
> >and eat the eggs that they layed. I have not
> observed with aus yet.
> >Ii is also common that other females will eat each
> other's eggs. I
> >have never seen a male pick at a mop.
> > 
> >This seems to be part of an inborn genetic survival
> stratergy: why
> >allow other geneticly unrelated stock to occupy the
> space you
> >want your children to occupy. This is partly also
> why there seems
> >to be no aggression between a male GAR and his sons
> while they
> >can be bloodthirsty towards each other.
> 
> Of course you don't mean that your siblings are not
> genetically related to
> you, for example having two siblings survive would
> transmit as many
> of your genes as having one child survive.
> 
> There are plenty of species that look after siblings
> for exactly this
> reason.  A classic example is Vervet monkeys (cite
> below) who signal the
> presence of predators, which warns the whole group
> but raises the risk of
> predation to the signaler, when the group of monkeys
> is closely related
> genetically (for example an isolated family band)
> but in geographic
> locations where lots of families intermingle, no
> monkeys signal predators,
> because you are no longer saving your family who
> carry your genes, but
> unrelated Vervet monkeys.
> 
> This is not to bash Tyrone, but he did raise the
> wonder in my mind if
> anyone knows if predation on siblings, young, eggs
> etc.  which seems to
> vary significantly across different Killifish
> species might be a similar
> function of the genetic isolation of the original
> species (or even
> location strain).  That is, perhaps Killies that
> come from smaller pond
> systems where most of the other Killies you meet are
> related to you
> genetically would be like the Striatums and
> Annulatus of the world, and
> ignore eggs and young, and stock from more open
> systems with more mixing
> of lineages and genes would be like my own gardineri
> Akure's who spend
> most of their life rooting through the java moss for
> young and even chowed
> 3/4 inch fry I mistakenly returned too soon. 
> 
> I'm not a biologist, but I do study evolution for a
> living.  I would
> welcome having my stylized facts corrected if I have
> paraphrased
> incorrectly.
> 
> james.
> 
> 
> Cheney and Seyfarth (1990).  ``How Monkeys See the
> World.''  
> U.Chicago Press.
> 
> ---------------
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