Xref: utzoo sci.bio:780 soc.men:2357 soc.women:8767 sci.misc:705
Path: utzoo!utgpu!water!watmath!clyde!rutgers!super.upenn.edu!eecae!nancy!msudoc!straney
From: straney@msudoc.ee.mich-state.edu (Ronald W. DeBry)
Newsgroups: sci.bio,soc.men,soc.women,sci.misc
Subject: Re: Rape a reproductive advantage?
Message-ID: <248@nancy.UUCP>
Date: 13 Jan 88 02:33:17 GMT
References: <517@gtx.com>
Sender: usenet@nancy.UUCP
Reply-To: straney@msudoc.UUCP (Ronald W. DeBry)
Distribution: na
Organization: Michigan State Univ., Engineering, E. Lansing
Lines: 43

>I expect there's an evolutionary advantage.  Rapists probably reproduce
>better than non-rapists.
>
>Keith Doyle


This posting certainly generated a lot of activity on a
relatively quiet newsgroup, didn't it? (meaning sci.bio)
Most of it about the definition and frequency of rape in
non-human animals.

I would like to comment about the first question - why doesn't
this trait increase in frequency.  Natural selection on a single
trait isn't magic, it's just a mathematical consequence of
differential reproduction.  BUT, before we can talk about natural
selection being responsible for maintaining or affecting the
frequency of a trait in a population, several criteria must be
met:

		1. There must be variation in the population

		2. The trait must cause a variation in reproductive
            success, either positive or negative

		3. The trait must be heritable


The first is usually obvious, it's the second that everyone gets
excited about.  Regardless of the trait, people like to start
making arguments about how it either increases or decreases
fitness.  Often there are equal numbers of arguments for both
conditions for a single trait :-).  Actually measuring fitness is
a REAL problem.  See both John Endler's recent book and a rather
sobering essay by Lewontin in the (I think) 1985 edition of
"Oxford Surveys in Evolutionary Biology."

The last criterion is the easiest to forget in all the hupla over
fitness values, and this is the one that human rape clearly
fails.  Rape is a social, not a genetic problem; so the question
of reproductive success is moot.


Ron DeBry   Dept. of Zoology  MSU