jimmenegay{at}sbcglobal.net (Jim Menegay) wrote in
news:c5qbs3$1c14$1{at}darwin.ediacara.org: 

> William Morse  wrote in message
> news:... 
> 
>> One of the reasons I like the idea of e  is that it helped me
>> understand how symbiosis can evolve, which is something I have
>> puzzled over for a while. Obviously mutualism and commensalism is
>> easy - there is a benefit for one or both parties with no cost for
>> the other. But symbiosis seems to requires a cost from both parties.
>> The cost is more than made up for by the benefit, but how does one
>> start this process? There is no possibility of kin selection, and
>> probably no possibility of reciprocal altruism  since the two are
>> different species with no common communication pathways. 
> 
> I don't think I understand "no possibility of reciprocal altruism 
> since the two are different species with no common communication
> pathways." 

Your misunderstanding is because I was trying to stretch Hamilton's rule 
to cover interactions between species (where r is obviously 0) by using 
your concept of ecological competitiveness. In practice  this is probably 
too much of a stretch for Hamilton's rule, which after all was focused on 
relatedness.  

 
 
> The real trouble with with rb>c is not repaired by adding
"e" to the
> rule.  The trouble is that these models only deal with unilateral
> behaviors caused solely by the genetics of the donor.  To really begin
> to understand social and commensal phenomena, we need to come up with
> models that handle reciprocity.  These will be models in which the b's
> and c's are determined by the genetics of both parties, in a kind of
> organism-level reprise of the gene-level phenomenon of epistasis.
> 
> Although such models are naturally formulated using the payoff matrix
> of game theory, there is something wrong with both the ESS and the
> Nash equilibrium as a solution concept.  Someday, someone will come
> up with the right way of thinking about this.
> 
> In this sense, I almost find myself agreeing with Edser.  The trouble
> with Hamilton's kin selection is that it has diverted theorists from
> the really interesting and important problems.  In this sense, I think
> that my idea of "e" is just another diversion.  It is just an
> elaborated unilateralism, when what we really need to understand is
> bi-lateralism and eventually multi-lateralism.


I think we have to be careful about becoming too anthropocentric, or even 
too mammalocentric. The nice feature about Hamilton's rule is that it 
applies across all taxa. But I agree that once we get into repeated 
interactions between individuals who can recognize each other and 
remember past interactions, it is time to move beyond the simplicity of 
kin selection. 


However I do not think that the idea of "e" should be ignored even in 
complex social interactions. One of the key principles in ecology is 
competitive exclusion from a niche. But this is typically applied to two 
different species. Yet the same competitive pressure that applies to the 
two different species also applies to conspecifics. This pressure may be 
reduced by relatedness - the flip side of Hamilton's rule - but it is 
still omnipresent.

Yours,

Bill Morse
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