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Re: COWBIRDS....SHUDDER & nest predation




On Sat, 30 May 1998, Bill Adlam wrote:
> It's hard to see why it would be worthwhile for the parasite parents to 
> take revenge on alert hosts.  Maybe it leaves more food for less 
> discriminating parents nearby to feed to parasite chicks.  Or it might 
> drive the pair off, to be replaces by another, perhaps less selective, 
> couple.

Or, more simply: slightly bigger parasite parents scare host
(foster??) parents off nest.  They lay their egg among host's eggs.  Days
later parasite parents return to rate host parental performance.  They
drive host parents off nest again.  If their baby is being well taken care
of, they leave.  If baby has been ejected they improve their own future
chances by eating host's babies just for the food of it..  Ultimately this
simple rule could translate into selection for a gene for parasite
tolerance among host species.

On a more general note, although evidence of any of this stuff is unlikely
to come to light, looking to extant egg-laying species for behavioral
analogies is smart.  I believe it is likely that many such behaviors
existed--and more that we can't possibly imagine.