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From: evs@duke.cs.duke.edu (Ed Simpson)
Newsgroups: sci.bio
Subject: Re: An All Female Species of Fish!
Message-ID: <9592@duke.cs.duke.edu>
Date: Mon, 4-May-87 14:55:58 EDT
Article-I.D.: duke.9592
Posted: Mon May  4 14:55:58 1987
Date-Received: Tue, 5-May-87 03:34:26 EDT
References: <1055@thebes.UUCP> <9576@duke.cs.duke.edu> <1640@zeus.TEK.COM>
Reply-To: evs@duke.UUCP (Ed Simpson)
Organization: Duke University Medical Center, Durham, NC
Lines: 30

In article <1640@zeus.TEK.COM> dant@tekla.tek.com (Dan Tilque) writes:
>One aspect of parthenogenic reproduction which seems to be common in all
>of the species mentioned so far, is that the parthenogenisis seems to
>be stimulated by mating behavior or sperm from the males of a related
>species.  This implies that the parthenogenic females have to remain
>recognizable as females by those which engage in mating behavior with them.
>
>They also would have to continue to share at least part of the same
>habitat as those males.  (Lucius C. made a reference to this in an earlier
>posting.)
>
>I would think that these two restrictions would help maintain the
>identity of the species.

In the case of the fall cankerworm mentioned earlier, egg maturation in
the parthenogenetic female is stimulated by mating with a male (of the same
species) from the sexually reproducing segment of the local population.
On occasion, the male sperm is successful in fertilizing the egg.  This would
provide a small degree of gene flow between parthenogenetic lines.  Even
very low gene flow rates could prevent significant genetic divergence
between lines, thus, maintaining the species identity.  The same thing
could be happening with the mollies.

For a discussion of the effects of gene flow on genetic divergence between
populations see J. Antonovics, The Nature of Limits to Natural Selection,
Ann. Missouri. Bot. Garden  63:224-247,  1976.

-- 
UUCP: {decvax, seismo}!mcnc!duke!evs  ARPA: evs@cs.duke.edu  CSNET: evs@duke
Ed Simpson, P.O.Box 3140, Duke Univ. Medical Center, Durham, NC, USA 27710