Re: Jim's Hamilton's rule prize

From: William Morse (wdmorse_at_twcny.rr.com)
Date: 01/17/05 

Date: Mon, 17 Jan 2005 00:53:34 -0500 (EST)

wlhunt@earthlink.net (William L Hunt) wrote in news:cs23kg$2jc2$1
@darwin.ediacara.org:

> On Tue, 11 Jan 2005 03:45:41 +0000 (UTC), William Morse
> <wdmorse@twcny.rr.com> wrote:
>
>>"John Edser" <edser@tpg.com.au> wrote in
>>news:crikr0$1198$1@darwin.ediacara.org:
>>
>>
>>
>>>> BM:-
>>>> John won't
>>>> be convinced either, despite the fact that nature has already
>>>> performed the experiment (the preferential evolution of eusociality
>>>> in haplodiploid insects) and shown that Hamilton was correct.
>>>
> WH:-
> This statement makes me just a bit uncomfortable so I will add some
> comments. Clearly you think that the dozen or more times that
> eusociality has evolved in hymenopterans is a consequence of a higher
> r value than would be expected in dipoid species (the Hamilton
> argument of higher sister-sister relatedness). I think it is a
> consequence of their genetics but not necessarily or wholly from some
> higher r value.

I appreciate your comments. My statement was an overstatement of the case
for Hamilton's rule, but then carefully worded statements don't tend to
generate much response on the newsgroup :-). At least we are discussing
examples from the real world and not arguing about what must or must not
be true because otherwise your or my sensibilities would be offended.

> First there can be other advantages for the evolution of sociality
> that come from the haplodiploidy genetics but that have nothing to do
> with a higher r value. Second, since Wilson wrote his "Sociobiology"
> (in the 70's ?) many measurements have been made of r values in these
> species using communal nests formed of many fertile females. These r
> values are much lower than was expected. Even Hamiliton noted that, in
> cases where it was thought all were sisters, many unrelated females
> must be getting in. As a somewhat extreme example is the quasi-social
> communal halictine bee L. hemichalceum. It has a genome measured r of
> .15 . The females, all of the same generation, are all fertile but, in
> a very social way, they raise the brood communally. If they were
> diploid the r would be lower but the r value seems so low already that
> it does not seem to be what is "driving" this social behaviour.

Isn't one of the reasons Hamilton proposed his model was to address how
altruism can get started?. Positive sum games can drive themselves, but
can be difficult to start. The r of .15 may well be enough to start
communal breeding - especially since this is an average, and in some
hives will be higher. If such a hive happened to coincide with an allele
that favored communal care vs. individual care, then the increased
productivity of that hive would spread. But, of course, positive sum
games are also subject to cheating. In fact Wilson notes a number of
species of ants that are brood parasites. In this case, of course, the
"cheating" is by a different species. Is there some aspect of the
halictine behavior that prevents cheating? I note a recent reference in
Discover to research on paper wasps that shows punishment of wasps that
whose facial markings were doctored to show a false status.

> In many subsocial "routes to sociality" when one calculates the
> important r value, it is little different from that if the species was
> a diploid. A quick example. In temperate seasonal singly-mated
> subsocial bees, the females mature and help their mother the first
> season then hibernate and become fertile egg layers the second season.
> What is the r value for helping their mother produce more offspring
> than she could by herself. The r is .5 since the mother will produce
> essentially equal number of females (r=.75 sister-to-sister) and
> males(r=.25 sister-to brother). This is the same r as a diploid would
> have. So is there no advantage to the hymenopteran over a similar
> diploid in this case? There is but it comes from the fact that female
> hymenopteran's can easily switch from producing females to males,
> something that is impossible for a diploid that uses X-Y sorting to
> determine sex. The hymenopteran female will produce her helping
> daughters all early in the season so they can help for the maximum
> length of time, and produce the males only late in the season. A
> dipoid simply could not do this and would not match the productivity
> of such a seasonal hymenopteran nest.

But isn't this simply an argument for haplodiploidy as an advantage over
diploidy (by partially avoiding the "cost of sex"), rather than either
proof or disproof of the connection between Hamilton's rule and
eusociality? As an aside, Wirt in another thread noted the partially
parthenogenic aphids, which achieve a similar result by producing
parthenogenetically during the season and sexually only late in the
season. Helping the mother may itself be an example of Hamilton's rule,
but not based on a haplodiploid connection. I realize that the question
of helping raise younger siblings (observed in many animals, e.g. cichlid
fishes, meerkats, gray jays, and elephants to name a few) is a topic of
some debate as to whether and to what extent there is kin selection
involved.
 
> Another advantage of the haplodiploidy genetics that rarely is
> mentioned but I find most elegant is the general absence of genetic
> disease in the advanced eusocials. Since, in hymenopterans, recessive
> lethal and seriously deleterious alleles are exposed and removed in
> males, and males may make up only 1% of a nest, they might be thought
> of as almost free of such recessive genetic disease.

A very interesting point. I believe you had previously made the point
about the removal of deleterious alleles in haplo-diploid males,but I did
not make the connection at that time that this would encourage the
development of "sister" societies. Perhaps you could enlighten me as to
how this fits in with Fisher's rule for equal investment in males and
females. I'm a little fuzzy on how that works with haplodiploid species.

Yours,

Bill Morse

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