William Morse wrote:

> I had already been thinking (based on Bob's discussion of mutualism 
> related to Hamilton's rule in this thread and some comments in Wilson's 
> "Sociobiology") about some other implications of Hamilton's
rule. Jim has 
> done a nice job of showing some of the possibilities, and  the 
> implications for selfishness might be of some evolutionary significance. 
> Hamilton or others may well have recognized this, but I haven't seen it 
> discussed in SBE.
> 
> My thought was to reverse rb>c and discuss the prohibition on selfishness 
> as rc < b (the net cost of a selfish action on relatives must be less 
> than the benefit to the individual in order for a selfish behavior to 
> spread), but I will bow to the convention that has been established and 
> let "b" remain the effect on relatives (with a positive sign
for benefit 
> and negative sign for cost) while c is the effect on the individual (with 
> a positive sign for cost and negative sign for benefit) despite the 
> potential for confusion because of the reversed signs for individual vs. 
> relative benefit.
> 
> 
> No matter the convention, once we adopt Hamilton's concept of inclusive 
> fitness (which John Edser may never do), we not only recognize that 
> altruism can occur via kin selection if rb>c, it also follows that 
> extremely selfish behaviors will not be selected if rb (with a negative b 
> in the case of a selfish behavior that has a negative effect on 
> neighboring conspecifics, e.g. excessive hoarding behaviors) is less than 
> c (which is also negative because it is a benefit to the individual).  
> 
> I might note as a  correction to Jim's analysis that spite is not 
> forbidden if kin can be differentiated from non-kin. In this case the 
> sign of b  can depend on the value of r, and rb can still be greater than 
> c if c is generally small (as has been previously noted rb is actually a 
> sum over r, in this case with a varying b) 
> 
> 
> 
> 
> With regard to kin selection, a weakness of Hamilton's rule is in getting 
> an altruism gene established in the first place. If the gene isn't at 
> least locally widespread, the r factor will in fact be low.  For the flip 
> side - the inability for a selfish gene to spread - the reverse is true, 
> since the more a selfish gene spreads, the greater the selection pressure 
> will be against it. 
>  
This is true for the first generation, after that it depends on either 
the ability to recognise kin, or aggregation of kin.

Of course, for behaviour like parental care, the problems are reduced.

> 
> Is the flip side actually signficant in evolution? Since it is 
> essentially a negative effect, one cannot find examples showing it. 

I think the approach would be to correlate numbers/strengths of 
altuistic behaviours with relatedness of individuals that an individual 
interacts with.  This needs the right system to try it in - I'll leave 
the problem of finding such a system to the naturalists out there.

Now, when do we start insulting each other?

Bob

-- 
Bob O'Hara

Dept. of Mathematics and Statistics
P.O. Box 4 (Yliopistonkatu 5)
FIN-00014 University of Helsinki
Finland
Telephone: +358-9-191 23743
Mobile: +358 50 599 0540
Fax:  +358-9-191 22 779
WWW:  http://www.RNI.Helsinki.FI/~boh/
Journal of Negative Results - EEB: http://www.jnr-eeb.org
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