[Taxacom] Facultative trimorphism (was: Geodorcus sororum)

Kenneth Kinman kennethkinman at webtv.net
Sun Jul 4 08:53:41 CDT 2010

Hi Stephen,
       I disagree.  I think that it very much matters how the speciation
(or subspeciation) came about.  As Rowland noted, "facultative"
trimorphism and "genetic" trimorphism operate by different evolutionary
       If the males of Geodorcus sororum are the result of facultative
trimorphism (or dimorphism), caused by environmental factors rather than
genetic changes, then a swing back to earlier environmental conditions
could more easily result in a return to beta or gamma males (over alpha
      In any case, it apparently has not been demonstrated that the
males of Geodorcus sororum would be unable to interbreed with Geodorcus
capito females, or even whether Geodorcus sororum females would be
unwilling to mate with Geodorcus capito males.  Therefore, I wouldn't be
surprised if Holloway changes her mind again in the future, and goes
back to her original view.  Especially if facultative trimorphism was
Stephen Thorpe wrote: 
        Yes, along with the gross shape of the mandibles, and other
characters ... but it doesn't matter how the speciation came about. It
may have come about as result of normal allometric polymorphism, but it
has allegedly "crossed the line" (of reproductive isolation) in this
case ... 

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